Part I. The Von Braun Cyanogen-Bromide Reaction: Ii: Application to N-Aryl-Pyrrolidines. Part Ii: The Synthesis of Some Guanidino Amino Acids

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P a rt I .

THE VON BRAUN CYANOGEN BROMIDE REACTIONS IIs APPLICATION TO N-ARYL PYRROLIDINES.

P a rt I I .

THE SYNTHESIS OF SOME GUANIDINO AMINO ACIDS.

D is s e rta tio n Subm itted in P a r t i a l F u lfillm e n t of th e Requirements For th e Degree of Doctor of Philosophy In The F a cu lty of Pure Science Columbia U n iv ersity

By

M ilton Green

New York C ity 1951

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To

P r o f e s s o r R o b e r t C, S l d e r f ie ld

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A ck n o w led g m en t The a u t h o r w is h e s t o e x p r e s s h i s a p p r e c i a t i o n t o E l i L i l l y a n d Company J b r a g r a n t i n c o n n e c tio n w ith t h i s r e s e a r c h .

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PART I :

THE VON BRAUN CYANOGEN BROMIDE REACTION. I I . APPLICATION TO N-ARYL PYRROLIDINES.

In tro d u c tio n The re a c tio n of cyanogen bromide upon n itro g e n h e te ro c y c le s, f i r s t d escrib ed by von Braun, lead s to a s e r ie s o f in te r e s tin g and p o te n tia lly u s e fu l bromoalkyl cyanamides.

Because of th e s e le c tio n

o f s e v e ra l o f th e se compounds as in te rm e d ia te s in t h i s research* th e re a c tio n by -which th ey a re formed was deemed worthy of f u r t h e r stu d y . E ld e r f ie ld and Hageman^ ( l)

R. E ld e r f ie ld and H. Hageman, J . Org. Cham., 14» 605 (1949)*

s tu d ie d t h i s re a c tio n in d e t a i l and considerably extended i t s a p p lic ­ a b i l i t y , emphasis being p laced on th e manner in which s u b s titu te d p y rro lid in e s and ethylenim ines undergo rin g cleavage w ith cyanogen bromide.

P r io r to t h e i r work, no d a ta was a v a ila b le on th e r e l a tiv e

amounts o f th e two p o ssib le products r e s u ltin g from th e cleavage of 2 unsym m etrically s u b s titu te d p y rro lid in e s , although von Braun (2) (a) J . von Braun, B e r., 40, 3914 (1907); (c) 43, 1353 (1910) j

(d) 49, 2624 (1916);

(b) £2, 2035 (1909) J (e ) 51, 96 (1918) ;

( f ) J . von Braun and E« A ust, i b id . , 47, 3023 (1914). had c a r rie d out ex ten siv e s tu d ie s of rin g opening v s. d e a lk y la tio n of n -a lk y l p y rro lid in e s and p ip e rid in e s . The r e a c tio n o f l-n -b u ty l-2 -m e th y l p y rro lid in e w ith cyanogen

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bromide was found to proceed smoothly, giving a 98$ y ie ld of a crude m ixture o f isom eric bromoalkyl cyanamides.

These were sep arated by

re flu x in g w ith diethylam ine, whereupon I I , the prim ary h a lid e , re a c te d com pletely t o give a b a s ic diethylam ino d e riv a tiv e t h a t was e x tra c te d w ith a c id , and I I I , th e secondary h a lid e , did n o t r e a c t a t a l l .

BrCN -11^ i C4.H1

*

Br-(CH2 )3-CH-CH3

oh3- 8-(o h2 )3-m.c4h9

N-CN

■C H i

Br

CN

III

K h

II

(EtJgNH

CH 3 (E t) -N-(CH ) -C4j-C H 2 2 3 it 49 H CN

Two runs in benzene s o lu tio n , adding a benzene s o lu tio n of th e p y rro lid in e slow ly to a benzene s o lu tio n of cyanogen bromide gave id e n tic a l crude y ie ld s o f 70$ o f I I and 26$ of I I I , The products o b tain ed from th e re a c tio n o f cyanogen bromide w ith t e r t i a r y amines a re c o n s is te n t w ith th e form ulation of th e re a c tio n as proceeding by a com bination of SN1 and SN2 mechanisms.

The i n i t i a l 2(a ) form ation o f an in te rm e d ia te complex was p o stu la te d by von Braun' R3Ni

♦

BrCN

[RjNCN]

Br

RgNCN ♦ RBr

This i s in agreement w ith th e mode o f cleavage o f cyanogen bromide or ch lo rid e in a l k a l i

3

(3) (a ) J . Nef, Ann. . 287 , 265 (1895)J 23, 559 (1946).

(b)JKLeinberg, J . Chem. Ed*,

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t o y ie ld a n eg ativ e broimlde o r ch lo rid e Ion, but th e is o la tio n of an a d d itio n compound has never been re p o rte d except in th e re a c tio n o f 4 quinine (4 )

T. Shimidzu, J . Pharnu Soc. Japan, 543* 56 (1927).

and th e n a tu re o f th e in te rm e d ia te compound in t h i s case has not been determ ined.

D iscussion S u b s titu tio n o f a phenyl group fo r th e b u ty l, which de­ creased markedly th e b a s ic ity o f th e n itro g e n , made th e p y rro lid in e much le s s re a c tiv e toward cyanogen bromide, and th e re a c tio n was n o t a s clean c u t. The re a c tio n of l-p h e n y l-2-raath y lp y rro lid in e w ith cyanogen bromide was c a r r ie d out in a manner e x a c tly comparable to t h a t used by E ld e r f ie ld and Hageman'1'f o r the 1 -b u ty l d e r iv a tiv e .

Two runs in benzene,

one adding th e p y rro lid in e to cyanogen bromide s o lu tio n over a p eriod o f a h a lf hour a t room tem perature and th en re flu x in g f o r an hour and a h a lf , and th e o th er adding th e p y rro lid in e during a two hour p eriod a t th e r e f lu x tem perature gave p r a c tic a lly id e n tic a l r e s u l t s ,

20% of

th e unreacted p y rro lid in e was recovered as th e hydrobromide, 20% a d d itio n a l a s th e fre e base, and $6% as th e

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-4 “ isom eric rin g opened products including dehydrohalogenated d e riv a tiv e , a t o t a l reco v ery of 96$ . The isom eric bromoalkyl cyanamides were sep arated and id e n tif ie d according t o th e follow ing scheme, usin g th e procedure developed by Hage1 man and E ld e r f ie ld . The p y rro lid in e hydrobrondde, V III, so lu b le in benzene, was obtained in c r y s ta llin e form when th e solvent was removed and anhydrous e th e r added. CH~ i + CN

JJ CH -C-(CH ) -N3 , 2 3, Br CN

VI

V II

o

-N-CH -CH - 8=8 . CH , 2 2 3 CN

HBr VIII

IX

/ N (Et)oNH tC H 3^ ----:------- * (E t) N-(CH ) -C-N2 2 3 ,t

CH3

H2so4 *

( E t)2N-(CH2 ) 3-C-N-

HCN

HH

X XI H (E t) -N-(CHq) -C-Br 2

2 3

,

♦

-NH,

*3 VII IX I

a le . KOH

, , HH H2 -N-( CH ) -C=C-CH ------— , 2 '2 3 PtOr CN x

-® 2

*

t c5Hn CN

S V

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However, no hydrobromide formed when th e re a c tio n was c a r rie d out in e th e r s o lu tio n .

VI re a c te d smoothly w ith diethylam ine to give an

a c id -so lu b le d e riv a tiv e , X, w hile VII and IX d id not r e a c t a t a l l , and were in so lu b le i n a c id .

R efluxing X w ith d i l u t e s u lf u r ic a c id

removed th e GN group, g iv in g ^ -d ie th y lam in o -a -m e th y lb u ty la n ilin e . The compound was analyzed as th e c i t r a t e , and gave no dep ressio n when a mixed m elting p o in t was tak en w ith a c i t r a t e of an a u th e n tic sample 5 Bergmann (5)

E. Bergmann, B r it. P a t. 547,301 (1942).

claim s i t s p re p a ra tio n by re d u c tiv e a lk y la tio n from noval ketcne and a n ilin e , and c ite s th e p re p a ra tio n of t h i s s p e c ific substance as one o f h is examples.

N ev erth eless on r e p e titio n of t h i s work no tra c e o f

th e d e sire d product could be is o la te d .

This re a c tio n i s supposed to

proceed v ia th e S ch iff* s base a s an in term ed iate, but sin c e the eq u ilib riu m fo r th e form ation o f Schiff* s bases i s unfavorable a t room tem perature, re d u ctio n o f th e ketone probably took p la c e in s te a d 6 Shiho (6)

D. Shiho, J . Chem. Soc. Japan, 65, 135 (1944). mm

m m m ^m

re p o rts th e p re p a ra tio n o f *6 -diethylam ino-ar-m ethylbutylaniline by a lk y la tin g a n ilin e w ith 5- d i e t hylam ino-2-ethoxypentene-2 . (E t) -N-(CH ) -C-CH + HC(QEt) - J iB S . > (E t) -N -(C H ) -C-CH ~ ^ ' P , J/ ^ ^2 '3P f* 3 QEt A

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— 6—

Barber and Wragg (7)

7

H. Barber and W. Wragg, J . Chem. Soc. , 1946, 610.

have prepared tetrahydroplasraochin by a s im ila r re a c tio n , condensing 6-m eth o x y -l,2, 2, 4-te tra h y d ro q u in o lin e , e ith e r w ith

5-d ieth y lam in o -2-

ethoxypentene-2, or w ith 5-d ie th y lam in o -2, 2-diethoxypentane, from which th e former compound i s formed on heating*

Barber

7a

(7a) H* B arber, p riv a te communication to E* E ld e r f ie ld . has prepared plasmochin by reducing in th e presence o f palladium th e a n i l formed by condensing 6-methoxy-8-am inoquinoline w ith 5- d ie th y lamino-2, 2--diethoxypentane. A lk y latio n of a n ilin e w ith noval bromide gave th e d e sire d p ro d u ct, b u t in poor y ie ld . The m ixture o f secondary h alid e and u n sa tu ra te d compound (V II + IX) could not be d i s t i l l e d .

I t was c h a ra c te riz e d by dehydrohalogenating

w ith a lc o h o lic potassium hydroxide, reducing th e double bond formed w ith hydrogen and a platinum oxide c a ta ly s t, and f i n a l l y hydrolyzing o f f th e CN group w ith d ilu te s u lf u r ic a c id .

The product was compared w ith n -a n y l-

a n ilin e prepared by a lk y la tin g a n ilin e w ith amyl bromide, and n e ith e r th e o x a la te nor to s y l d e riv a tiv e gave a depression on mixed m elting p o in t de­ te rm in a tio n .

In most c ases, th e u n sa tu ra te d compound formed in th e r in g

opening was n o t is o la te d or determ ined, but was c a lc u la te d as being eq u iv a len t to th e hydrobromide formed.

As a check in two ru n s, and

in th o se cases where th e hydrobromide was n o t c r y s ta llin e , th e m ixture o f V II and

IX rem aining a f t e r re a c tio n w ith diethylam ine was dehydrohalo-

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genated w ith a lc o h o lic a l k a l i , and th e halogen determ ined, th u s giving th e amount of V II in th e m ix ture.

IX was th en obtained by differen ce*

The two methods gave r e s u l t s i n close agreem ent. From one run in which th e secondary h a lid e being dehydrohalogenated was allow ed t o rem ain in c o n tact w ith th e a lk a lin e a lc o h o lic s o lu tio n 16 h o urs,, th e s o le product of red u c tio n , obtained in e x c e lle n t y ie ld , was a b a s ic , oxygen-containing compound, showing th a t th e so lv en t had p a r tic ip a te d in th e re a c tio n .

I t was shown t o be N-amyl-N-phenyl

e th y liso u re a , formed by th e a d d itio n of a lc o h o l to th e cyanamide under th e in flu e n c e o f a c a ta ly tic amount of a l k a l i .

I t to o formed n-am yl-

a n ilin e on a c id h y d ro ly s is.

oyrv, CN

IX

O i“A C=NH i OEt

w

O

-f< ¥ u C=NH i OEt +

XII

H

X III H

The a d d itio n o f a lc o h o ls to cyanamides t o give iso u reas i s a 8 g e n e ra l one, u s u a lly proceeding under th e in flu en ce of a c id s , (8) (a ) R» McKee, Am. Chem. J . , 26, 209 (1901); Chem. S o c., 21, 136 (1899);

(b) F. Dains, J . Am.

(c) W. Bruce, ib id . , 26, 419, 449 (1904).

and g e n e ra lly re q u irin g s e v e ra l days fo r com pletion.

This re a c tio n i s

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8-

f u r th e r discu ssed in P a rt I I in connection w ith th e form ation o f 2-im ino-3- b u ty l o x a zo lid in e. I t has a ls o been re p o rted as tak in g place by h eatin g w ith 9 equim olecular amounts o f sodium e tb y la te o r potassium hydroxide (9)

R, McKee, Am* Chem, J , , 42, 1 (1909).

but th e y ie ld s , e s p e c ia lly in th e l a t t e r case, a re very poor.

There

i s no in d ic a tio n from th e se few re p o rts th a t th e re a c tio n may ta k e p lace under very m ild c o n d itio n s, o r th a t th e e f f e c t of th e a l k a l i i s a c a ta ly tic one, Ethylphenylcyanamide, allowed t o stan d f o r twelve hours in an a lc o h o lic s o lu tio n co n tain in g 1/10 eq u iv alen t of potassium hydroxide, was converted to N -ethyl-N -phenyl e th y liso u re a in 85$ y ie ld . The p ro p o rtio n s of ring-opened products obtained from th e re a c tio n o f l-p h e n y l-2-m e th y lp y rro lid in e , about 20$ of th e prim ary h alid e and 80$ o f th e secondary, was alm ost th e exact re v e rse of t h a t obtained from th e N -butyl d e riv a tiv e .

To show what e f f e c t th e b a s ic ity of th e n itro g e n

has on th e d ire c tio n o f r in g opening in t h i s re a c tio n , th e p-methoxyphenyl and p-chlorophenyl d e riv a tiv e s were prepared and tre a te d s im ila rl y . S u b s titu tio n of a methoxyl group in th e p -p o sitio n o f th e phenyl group in cre ased s lig h t l y th e amount o f rin g opening a t a, whereas s u b s titu tio n o f a c h lo rin e in t h i s p o s itio n gave somewhat more rin g opening a t b . C arrying out th e re a c tio n in a more p o lar so lv en t a ls o gave more opening a t bo

The r e s u l t s obtained in t h i s s e r ie s a re summarized in th e ta b le below* These d a ta are c o n s is te n t w ith th e form ulation of th e re a c tio n as

ta k in g place by means of sim ultaneous Shi and M2 displacem ents by bromide on th e in te rm e d iate quaternary complex and w ith th e assum ption th a t th e de­ creased b a s ic ity o f th e n itro g e n caused by s u b s titu tio n of a Fhenyl f o r an a lk y l group fav o rs th e io n iz a tio n re a c tio n over th e second o rder displacem ent, th e re b y causing an in c rea sed amount of opening a t b* Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

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Table I

£fW a-

R

Solvent

Prim ary h a lid e (opening a t a)

Opening a t b Secondary ~ h alid e O le fin

H

e th e r

13.8g

31.2$

H

benzene

19.7

58.5

H

21.3

56.9

H

2 0 .1

58.5

22.4

15.7

58.7

25.6

H

a c e t o n i t r il e

H

a c e tic a c id

0 % 21.3 21.3

^ ,10.

ch3o

e th e r

26.5

73.5

0

CH3O

benzene

22.5

53.6

23.9

16.7

49.9

33.4

Cl

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The £ -ch lo ro d e riv a tiv e re a c te d v ery slow ly.

Since the i n i t i a l

a tta c k o f cyanogen bromide i s assumed to tak e place through th e CN+ io n , th e use of a c a ta ly s t such a s f e r r i c ch lo rid e ought to f a c i l i t a t e th e r e a c tio n by forming th e complex (FeCl^Br)

CN .

This was found to be

th e case, about th re e tim es a s much product being obtained on re flu x in g w ith f e r r i c c h lo rid e in b enzene-ether fo r th re e hours, or w ith sta n n ic c h lo rid e i n benzene f o r two hours, as had been o b tain ed in re flu x in g benzene fo r th re e hours w ithout any c a ta ly s t.

Less th an te n p er cent of

th e ring-opened products c o n siste d of prim ary h a lid e when th e se c a ta ly s ts were used.

Although th e r e a c tio n i s f a c i l i t a t e d , th e lo s s of m a te ria l as

a r e s u lt o f t a r form ation and th e d i f f i c u l t y encountered in s e p a ra tin g th e d e sire d products makes t h i s u s e le s s as a p re p a ra tiv e method.

A clean er

p ro d u ct, in b e tte r y ie ld , i s o b tain ed m erely by re flu x in g f o r a longer p erio d of tim e, and w ithout lo s s of unreacted s ta r tin g m a te ria l which ta k e s p lace when th e c a ta ly s ts a re used. The t a r r y m a te ria l formed in t h i s re a c tio n was not in v e s tig a te d , but i t i s probably a t l e a s t in p a rt a trim e r of cyanogen bromide.

A

trim e r i s known to be formed by th e a c tio n o f aluminum c h lo rid e , and i s 10 claim ed t o be th e p r in c ip a l product (10)

R. S c h o ll and W. Norr, B e r.,

1052 (1900).

o f th e r e a c tio n o f cyanogen bromide and aluminum ch lo rid e on arom atic hydrocarbons, such a s benzene f o r exanple, to give b e n z o n itr ile . (11)

K arrer

P . K arrer and E. Z e lle r , H elv. Chim. A cta. , 2, 432 (1919).

on th e o th e r hand, claim s to g et good y ie ld s of b e n z o n itrile w ith no polymer form ation a t a l l , u sin g f r e s h ly prepared cyanogen brom ide.

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If

11

th e para p o s itio n i s s u b s titu te d , as in ja-xylene, no r e a c tio n ta k e s 1; p la ce a t a ll# D im ethylaniline, on th e o th e r hand, re a c ts smoothly ' (12)

0 . F o lin , Am. Chem. J . , 19, 332 (1697).

w ith cyanogen bromide and aluminum c h lo rid e to give th e £-bromo d e riv a t i v e , and a n iso le

8

g iv es m ostly th e jo-brorao compound, w ith a sm all

amount o f th e £-cyano compound a ls o being formed. N either jg -n itro a n ilin e nor ]>-cyanoaniline re a c te d w ith 1 ,4 - d ibrompentane.

Because of th e slu g g ish re a c tio n of th e £-chlorophenyl

d e r iv a tiv e , and th e s t i l l slow er re a c tio n to be expected w ith th e j>n i t r o and £-cyano compounds, th e sy n th esis o f p y rro lid in e s from th ese compounds was not attem pted by any o th er means. While th e re a c tio n o f cyanogen bromide on l-p h en y l-2 -m eth y lp y rro lid in e to give a preponderance of th e secondary h a lid e i s con­ s i s t e n t w ith th e probable mechanism of th e re a c tio n , i t was hoped t h a t a g r e a te r amount of th e prim ary h a lid e would be obtained th an was a c tu a lly formed.

When th e prim ary bromoalkyl cyanamide i s rea c te d

w ith diethylam ine and th e CN group removed by h y d ro ly sis th e r e r e s u lts an a-m eth y l- ^ -d ie th y lam in o b u ty l d e r iv a tiv e .

This grouping i s th e

sid e chain o f some im portant a n tim a la ria ls , such as plasmochin* In view o f th e preceding, th e re was l i t t l e hope .th a t th ese compounds could be sy n th esized in good y ie ld by means o f th e von Braun r e a c tio n , but th e p re p a ra tio n of plasmochin was n e v e rth e le ss attem pted. 6-M ethoxy-8-(21-m e th y l-p y rro lid in y l) quinoline (XIV) was prepared by condensing 6-methoxy-S-aminoquinoline w ith 1, 4-dibromopentane, and then re a c te d w ith cyanogen bromide.

Here th e re a c tio n i s fu rth e r com plicated

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by th e p resence of th e q u in o lin e n itro g e n , (13)

13

T. Shimidzu, J« Riarm. Soc. Japan, 529, 25 (1926).

b u t which ought to re a c t p r e f e r e n ti a lly w ith cyanogen bromide.

The

re a c tio n w ith quinine ( in chloroform a t 0°) follow ed by hy d ro ly sis CH.

CH_0

CH, +

BrCN

•>

XIV

(E t)2NH H CN (E t)2N-(CH2 ) 3-C-N-R CH.

Proposed sy n th e sis of plasmochin

"’“CO HN-CH-(CH2 )3-N (Et) 2 CH. 3 w ith flwunnia to give py-a~hydraxy-qu in in e hydrocyanide

plasmochin i s a good

example o f t h i s . The monohydrochloride o f XIV was. prepared and tr e a te d w ith cyanogen bromide i n th e hope t h a t by ty in g up th e q u in o lin e n itro g e n , o n ly th e p y rro lid in e n itro g e n would r e a c t.

When amino and s u b s titu te d

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amino q u in o lin es a re t r e a t e d w ith a c id , th e f i r s t p ro to n i s known to add to th e q u in o lin e n i t r o g e n . ^ (14)

E* S teck and G. Ewing, J . Am. Chem. Soc. , 70, 3397 (1948). In eth er-ch lo ro fo rm s o lu tio n , however, no r e a c tio n a t a l l took

place under the usual c o n d itio n s.

H eating in a sealed tube on th e steam

b ath fo r fo u r hours gave p rim a rily a carbonaceous re s id u e .

The sm all

amount o f u n id e n tifie d m a te r ia l sep arated from i t appeared to be id e n ti­ c a l w ith t h a t d esc rib e d below. The fre e base, on th e o th er hand, re a c te d w ith cyanogen bromide in e th e r s o lu tio n , but in s te a d of th e expected product, a 27% y ie ld o f a crude monobromo d e riv a tiv e (XV) m elting a t 95-98° a f t e r re c r y s ta lliz a tio n from hexane was ob tain ed .

This compound was id e n tic a l w ith t h a t obtained

on brom ination o f 6-methoxy-8- ( 2'-m e th y l-p y rro lid in y l)q u in o lin e (X II), u sin g bromine i n a c e tic a c id .

While th e p o s itio n of th e bromine was not

d e f i n it e l y a s c e rta in e d , i t i s most probably s u b s titu te d in th e 5- p o s itio n . 6-Methoxyquinoline and 6-methoxy-8-acetam inoquinoline both brom inate very ra p id ly in th e 5- p o s itio n .

e th e r

XV

+ BrCN

XIV

benzene

*

XV

♦

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XVI

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O ther cases of broraination by cyanogen bromide have been r e ­ p o rte d , in a d d itio n to th o se mentioned e a r l i e r a s being cataly zed by aluminum c h lo rid e . (15)

Benzene 15

V. Merz and W. W eith, B e r., 10, 746 (1877).

o r e a c ts a t 200 , and phenol (16)

R. S ch o ll and W, N orr, B e r., 33, 1555 (1900).

a t 130

o

to give only th e j>-bromophenol, in d ic a tin g how m ild a brom inat-

in g agent t h i s substance i s . o 17 i s brom inated a t 100 . (17)

The a r y l group in a r y l a m in o a c e to n itrile s

J . von Braun, Ber. , 41, 2100 (1908).

Acetophenone and e th y l a c e to a c e ta te a re both brominated. (18)

18

W. S tein k o p f, Ann., 430, 78 (1923). S te r ic hindrance o f th e bulky 2-m e th y lp y rro lid in e group in th e

8- p o s itio n was probably re sp o n sib le f o r th e f a i lu r e of th e expected a tta c k on th e q u in o lin e n itro g e n t o ta k e p la c e , sin ce t h i s grouping i s o r d in a r ily very r e a c tiv e toward cyanogen bromide.

However, t o confirm t h i s r e a c ti v i ty ,

6-m ethoxyquinoline was tr e a te d w ith cyanogen bromide in anhydrous e th e r . Form ation of a p r e c ip ita te began alm ost immediately a t room tem perature. This c o n siste d of a m ixture o f a hydrobromide o f s ta r t in g m a te ria l, most o f which could be se p a ra te d by m echanical means from th e remainder of th e s o lid , and an e th e r formed by re a c tio n of th e expected product w ith

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-1 5 -

m o istu re in so lv e n t, which had not been s p e c ia lly d rie d .

This compound

i s n o t solu b le in cold d ilu te sodium hydroxide, hydrochloric a c id , e th y l a lc o h o l, or e th e r , but i s hydrolyzed ra p id ly in warm hydro ch lo ric a c id back to 6-me thoxyquinoline. In th e hope th a t a h ig h er tem perature might b rin g about re a c tio n o f th e q u in o lin e n itro g e n in XIV, re flu x in g benzene was used as th e s o l­ ven t in s te a d o f e th e r .

The t o t a l y ie ld was somewhat lower th an th a t ob­

ta in e d p rev io u sly , and c o n s is te d of a m ixture in approxim ately equal q u a n titie s , o f th e bromo d e riv a tiv e o b tain ed in e th e r, and a cyano d e riv a tiv e t h a t contained no bromine.

The s tru c tu re of th e l a t t e r com­

pound was n o t determ ined, b u t q u in o lin ic a c id was obtained on a lk a lin e permanganate o x id a tio n , showing th a t th e CN group had not e n te re d th e p y rid in e rin g .

In a l l p r o b a b ility i t i s in th e 5 -p o s itio n , because in

ev ery in stan c e where cyanogen bromide r e a c ts t o introduce e i th e r Br or CN groups in to th e same m olecule, th e se groups e n te r th e same p o s itio n .

E xperim ental A ll m eltin g p o in ts a re c o rre c te d f o r stem exposure, and b o ilin g p o in ts a re u n co rrected .

Atmospheric p ressu re i s t o be understood u n less

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-1 6 -

otherw ise s ta te d . M icroanalyses by th e C lark M icro an aly tical L a b o ra to rie s, Urbana, I l l i n o i s ; M icrotech L a b o ra to rie s, Skokie, I l l i n o i s ; and th e Schwarzkopf M ic ro a n aly tica l L aboratory, Elm hurst, New York.

P rep a ratio n o f cyanogen bromide. The cyanogen bromide was e i th e r prepared according to the p ro 19 cedure o f Hartman and Dreger (19)

W. Hartman and E. D reger, Org, Syn« C o ll. V ol. I I , 150.

o r purchased from Eastman Kodak Company.

C ontrary to th e a u th o r’s s ta t e ­

ment, cyanogen bromide i s s ta b le , one batch having been kept in th e re­ f r i g e r a t o r f o r more th an one y ear w ith no sign o f decom position.

The

o nly p recau tio n s n e cessary i n handling are th o se re q u ired because o f th e compound’s extreme t o x ic ity . P re p a ra tio n of s u b s titu te d p y rro lid in e s . l-P h en y l-2 -m eth y lp y rro lid in e

- A m ixture o f 161.6 g . o f a n ilin e

and 200 g. o f 1 , 4-dibrom pentane ( 2:1 molar r a t io ) in a 1- l i t e r f la s k f i t t e d w ith an a i r condenser was warmed on th e steam b a th , shaking fre q u e n tly . White c r y s ta ls formed g ra d u a lly .

A fte r f if te e n m inutes, w ith about h a lf

th e volume a mass of w hite c r y s ta ls , th e re a c tio n , u n t i l now only m ildly exotherm ic, suddenly became vigorous.

The f la s k was cooled under running

w ater, but th e s o lu tio n continued to b o i l, and in a few minutes s e t to a s o lid m ass.

Five hundred m l. of 20% sodium hydroxide was added to

l i b e r a te th e b a s e s, and th e upper la y e r se p arated .

The aqueous s o lu tio n

was e x tra c te d w ith 2-100 m l. p o rtio n s of e th e r, and th e f ra c tio n s combined

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-1 7 -

and d rie d over potassium hydroxide. F ra c tio n a tio n gave 86 g . of o a n ilin e , b ,p , 83 /2 5 nmu, and 121.5 g. o f a p a le straw -co lo red liq u id w ith a p e tro le u m -lik e odor b o ilin g a t 133°/25 mm,, a y ie ld o f 87$.

A

p ic r a te , p r e c ip ita te d and r e c r y s ta lliz e d from 95$ e th an o l, m elted a t o 20 109-110 . S ch o ltz and F reim ehlt (20)

M. S ch o ltz and P. F reim eh lt, B e r., ^2, 850 (1899).

who p rep ared th e compound from th e same s ta r ti n g m a te ria ls by re flu x in g o in a lc o h o lic s o lu tio n , re p o rt a b o ilin g p o in t o f 134 /25 mm., and a o 21 p ic r a te as m elting a t 105 . Markwalder (21)

J . Markwalder, J . P ra k t. Chem., [2 ] 75. 329 (1907).

O re c o rd s th e m eltin g p o in t of th e p ic r a te as 110 . l-(]> 4 Ieth o x y p h en y l)-2-m ethylpyrrolidine,

In th e same manner as

was d escrib ed above, 35 g. o f p -a n is id in e (0.284 mol) was h eated on the steam b ath w ith 32.7 g. of 1,4-dibrom pentane (0.142 m ol).

A s o lu tio n of

5 .7 g . of sodium hydroxide (0 ,1 4 2 mol) in 250 m l. of w ater was added, th e m ixture shaken w e ll, and e x tra c te d w ith e th e r .

Most of th e p - a n is i-

d in e, b ein g more b a s ic , should remain behind in th e aqueous s o lu tio n as th e hydrobromide. A fte r d ry in g over magnesium s u lf a te , th e e th e r was removed and th e p roduct d i s t i l l e d .

A sm all amount o f j> -anisidine came over as a O / w hite s o lid , b .p . 80-100 C . / l mm., and th e bulk of th e m a te ria l from H 5 - l3 5 ° /0 .5 mm.

R e d i s t i l l a ti o n gave 21.2 g. (79$ y ie ld ) o f a c o lo rle s s

l iq u id , b .p . U 0 -1 1 2 ° /0 .2 mm.

I t was analyzed a s th e h y drochloride,

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-1 8 -

whioh was p r e c ip ita te d from e th e r e a l s o lu tio n by gaseous hydrogen c h lo rid e , and r e c r y s ta lliz e d from a lc o h o l-e th e r. A nal, C alcd, f o r C^yH^gNOCl:

N, 6 ,1 5 .

l-(£ -C h lo ro p h en y l)-2 -m eth y lp y rro lid in e.

Found:

N, 6.07,

A s o lu tio n of 35 g . of

1, 4-dibrom pentane (0.15 m ol), 40 g. of £ - c h lo ro a n ilin e (0.315 mol) and 2 g , of sodium io d id e in 200 ml. ab so lu te alco h o l was re flu x e d f o r 48 hours.

Only a viscous syrup remained on removal of th e solvent in ste a d

o f a c r y s ta llin e product.

The m a te ria l was tr e a te d as described fo r

th e phenyl d e riv a tiv e , recovered s ta r tin g m a te ria l d i s t i l l i n g a t o 115-130 /15 mm. through a 6 inch vacuum^jacketed Vigreaux column and th e product a t 115-130°/1 mm.

R e d is tilla tio n gave 19.95 g . o f a

c o lo rle s s v isco u s liq u id , b .p . 116- 120°/1 mm. which g rad u a lly s o lid i­ f ie d on stan d in g .

Y ield: 68$ .

Anal. C alcd. fo r C-^H^NCl: Found:

C, 67.12;

H, 7 .0 0 ;

C, 67-52;

H, 7.16;

N, 7 .1 5 .

N, 7 .0 5 .

6-Methoxy-8- ( 2 *-m e th y lp y rro lld in y l)-q u in o lin e (XIV).

Two hundred

grams o f crude commercial nucleus ( 6-methoxy-8-am inoquinoline) was p u r i­ f ie d by p r e c ip ita tin g i t a s th e hydrobromide w ith gaseous hydrogen bro­ mide from a 15$ s o lu tio n in a 9:1 chloroform -m ethanol m ixture.

The

sp a rin g ly so lu b le yellow s a l t , m .p. 246-247 , was suspended in 20CPml. o f w ater, th e s o lu tio n made a lk a lin e , and e x tra c te d w ith 4-500 ml. p o rtio n s o f e th e r .

The combined e x tr a c ts were d rie d over magnesium

s u lf a t e , th e so lv en t removed, and 400 m l. o f iso p ro p y l a lco h o l added. C r y s ta lliz a tio n was ra p id a f t e r cooling and seeding, giving 123 g. l i g h t yellow c r y s ta ls , m.p. 42-44°.

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-1 9 -

Condensation w ith 1,4-dibrom pentane may be e ffe c te d w ithout s o lv e n t, but the re a c tio n i s d i f f i c u l t to c o n tro l and le a d s to ex­ c e ssiv e t a r fo rm ation.

A so lu tio n of 78 g. o f nucleus and 52 g. of

1 , 4-dibrom pentane (a 2:1 r a tio ) in 150 ml. of b u ty l c e llo so lv e was re flu x e d g e n tly f o r 45 m inutes. P r e c ip ita tio n of nucleus hydrobromide 0 s ta r te d a t 110 , and by th e tim e th e r e f lu x tem perature was reached, th e mass o f c r y s ta ls in th e f la s k was almost s o lid .

The c r y s ta ls were

f i l t e r e d and washed w ith 200 ml* o f isopropanol in sm all p o rtio n s . F if t y - f i v e and f iv e /te n th s grams of th e hydrobromide was recovered ( th e o r e t i c a l 58.6 g . ) .

T h irte e n and s ix /te n th s grama (a % excess)

o f sodium m ethylate in 100 m l. methanol was added, th e sodium bromide f i l t e r e d o f f a f t e r coo lin g , and th e so lv en t then removed as com pletely a s p o s sib le under water-pump vacuum.

The resid u e was taken up in 300

m l. of anhydrous e th e r t o se p arate th e product from r e s id u a l s a l t s and sane t a r r y m a tte r, and d i s t i l l e d through a 6 inch jack eted Vigreaux column, y ie ld in g 27*2 g . , a 49% y ie ld , b o ilin g a t l 65- 170° / 0 . 3- 0 .8 mm., 0 w ith a b ath tem perature of 200 , The product i s a straw -yellow o i l , very v isc o u s, and darkens ra p id ly on exposure to a i r . so lu b le in organic so lv e n ts.

I t i s extrem ely 25 The r e f r a c tiv e index, n^ = 1.6326, re ­

mained unchanged on r e d i s t i l l a t i o n . A nal. C alcd. f o r C^H^NgO: Found:

C, 74.17;

H, 7.19;

C, 74.38;

H, 7 .4 4 J N, 11.57.

N, 11.7 6 .

P ic r a te , orange needles from 95$ e th a n o l, m.p. 167-168.5°o A nal. C alcd. f o r C^H ^N jO g: Found:

C, 53.64;

H, 4 .4 8 ;

C, 53.51;

H, 4 .4 6 ;

N, 14.86.

N, 14.9 5 .

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-

20'

Ring opening o f p y rro lid in e s w ith cyanogen bromide. l-P h e n y l-2-m eth y lp y rro lld in e - F ifte e n and n in e /te n th s grams o f th e p y rro lid in e (0*0987 m ol.) in 35 ml* o f benzene was added during one hour to a re flu x in g s o lu tio n of 13 g . o f cyanogen bromide (2% excess) in 60 m l. o f benzene. tu rn e d a l i g h t g reen .

During th e a d d itio n th e s o lu tio n g rad u ally

R efluxing was continued an a d d itio n a l h a lf hour,

and th e so lu tio n th en allow ed to stan d 16 Ijours

a t room tem p eratu re.

so lv e n t was removed under vacuum, th e re s id u a l green o i l taken up in 300 ml* anhydrous e th e r , le av in g behind 3»1° g« o f green c r y s ta ls , (VI) of th e hydrobromide o f s ta r t i n g m a te ria l, pale green te tra h e d ra from o e th y l alco h o l-d io x an e, m.p* 120-121 C. Anal. Calcd. f o r C^H^NBrs

N, 5*79.

Found:

N, 5*82.

The e th e r s o lu tio n was e x tra c te d w ith two 40 m l. p o rtio n s of 5% hydro­ c h lo ric a c id , the a c id e x tr a c t made alk alin e and then e x tra c te d w ith e th e r , y ie ld in g 4*41 g* o f a d d itio n a l recovered s ta r t in g m a te ria l. When th e rin g opening wa3 c a rrie d out in e th e r, no hydrobromide se p a ra te d . Following th e procedure of E ld e r f ie ld and Hageman,

1

so lv en t was

removed and th e bromocyanamide m ixture re flu x e d f o r fo u r hours w ith 20 g . of diethylam ine.

The excess was d i s t i l l e d o f f under vacuum, th e

resid u e a c id if ie d w ith d ilu te hydro ch lo ric a c id , and th e m ixture of secondary bromide and o le f in e x tra c te d w ith e th e r .

The a c id s o lu tio n

was made a lk a lin e and e x tra c te d w ith e th e r, y ie ld in g a f t e r drying over magnesium s u lf a te and removal o f so lv e n t, 3. 3I g . o f product, X, eq u iv a len t t o 3*40 g . o f prim ary h a lid e .

Eleven and f o r ty - e ig h t/

hundredths grams o f secondary bromide and o le f in was obtained from

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The

-21-

th e n e u tr a l f r a c tio n .

C a lc u la tin g th e o le f in formed as being eq u iv alen t

to th e hydrobromide is o la te d , and assuming th a t th e secondary h alid e was th e source o f a l l th e hydrobromide would make t h i s eq u iv a le n t to 12.53 g. o f secondary h a lid e .

The y ie ld of prim ary h alid e i s th e re fo re 21.3/6 o f

th e ring-opened products formed. 1 - (£-M ethoxyphenyl)-2-met h y lp y rro lid in e .

Following th e pro­

cedure d escrib ed above, 14#5 g . (0.075 mol) of 1- (£-roethoxyphenyl)-2m eth y lp y rro lid in e was added dropwise during one hour to a g e n tly re ­ flu x in g s o lu tio n o f 12 g . (0 . 114mol) cyanogen bromide in 50 ml. e th e r. Three and th irty -se v e n /h u n d re d th s o f unreacted s ta r t i n g m a te ria l was re ­ covered,

R eaction of th e resid u e w ith diethylam ine gave 4#20 g . o f a c id -

so lu b le product, and 11.95 g . of secondary h alid e, not soluble in a c id , a y ie ld o f 26.556 of prim ary h a lid e . The rin g opening in benzene was c a rrie d o ut by adding 17#5 g* (0.0 91 mol) o f th e p y rro lid in e in 35 m l. of benzene to 11 g . of cyanogen bromide in 55 m l. o f benzene.

Four and sev en /te n th s grams o f th e hydro­

bromide o f u n reacted s ta r t i n g m a te ria l was obtained, and 0 o88 g . of un­ rea c te d p y rro lid in e as th e f r e e base.

R eaction of th e ring-opened

isom ers w ith diethylam ine gave 4.67 g* o f a c id -so lu b le product eq u iv alen t to prim ary h a lid e , and 15*21 g . of a c id -in so lu b le m a te ria l, a m ixture of secondary h a lid e and o l e f in .

The y ie ld of prim ary h a lid e i s c a lc u la te d

to be 22. 556. l-(£ -C h lo ro p h en y l)-2 -m eth y lp y rro lid in e.

F ifte e n and o n e/ten th s

grams o f th e p y rro lid in e in 25 m l. o f benzene was added to 14 g . o f cyanogen bromide in 60 m l. o f benzene, and th e s o lu tio n re flu x e d f o r

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- 21a'

about 15 h o u rs.

Treatment as describ ed above gave 5*6 g . o f a resin o u s

e th e r-in s o lu b le resid u e t h a t undoubtedly contained some cyanogen h a lid e polymer in a d d itio n t o th e hydrobromide of s ta r ti n g m a te r ia l.

Four and

fifty -th re e /h u n d re d th s grams o f unreacted p y rro lid in e was obtained, and from th e ring-opened p ro d u cts, 2.10 g . o f diethylam ine product eq u iv alen t t o 2.15 g .o f prim ary h a lid e .

The per cen t of secondary h alid e in the

9*58 g . m ixture of secondary h a lid e and o le f in was determ ined by t i t r a ­ t i o n of an a liq u o t a f t e r conversion o f th e h alid e to th e io n ic form by tre atm e n t w ith a lc o h o lic a l k a l i .

The y ie ld of prim ary h alid e was c a l­

c u la te d to be 16. 7$ of ring-opened p ro d u cts. Using stan n ic c h lo rid e as c a ta l y s t.

To a s o lu tio n of 16.6 g .

o f th e p y rro lid in e and 12 g . o f cyanogen bromide in 60 m l. of benzene was added 20 g . of sta n n ic c h lo rid e in 35 m l. o f benzene.

The so lu tio n

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-2 2 -

tu rn e d dark brown im m ediately. t o sta n d l6 :h o u rsi;.

I t was re flu x ed fo r 2 hours and allow ed

The so lv e n t was then removed, 150 m l. of e th e r

added, and th e m ixture shaken w ith sm all p o rtio n s of 10$ hydro ch lo ric a c id u n t i l no more s ta r t i n g m a te ria l was e x tra c te d .

Three and f o r t y -

fiv e /h u n d red th s grams of u n reacted s ta r ti n g m a te ria l was recovered from th e a c id s o lu tio n .

The e th e r e x tr a c t, tr e a te d w ith d ie th y l amine in

th e u su al manner, gave 7*71 g . of a c id -in s o lu b le re sid u e , and only 0.44 g» o f the prim ary h a lid e product, a y ie ld of about 6$. The la rg e amount of black t a r formed in th e re a c tio n , in so lu b le in both e th e r and aqueous hydrochloric a c id was d iscard ed . S tru c tu re of prim ary h a lid e formed in th e rin g opening of l-p h e n y l-2 met h y lp y rro lid in e . F ra c tio n a tio n of th e a c id -so lu b le product obtained a f t e r t r e a t ­ ment o f th e ring-opened products w ith diethylam ine gave l-m e th y l-4 -d iethylaminobutylphenylcyanamide (30» b .p . 1 5 3 °/l* 5 -2 mn., w ith alm ost no 25 fo re ru n or re s id u e , = 1.5139* An o x a la te was p r e c ip ita te d from o e th e r s o lu tio n and r e c r y s ta lliz e d from dioxane. I t so ften ed a t 95 and m elted a t 93-100°. A nal. Calcd. f o r cig H27N3° 4 s Found:

C, 61,40;

H, 7*76j

c» 6 l »89»

H» 7 .7 3 ;

N, 12.03.

N, 12.11.

The cyano group was removed by re flu x in g 11 g. fo r 3 hours w ith 14 g . of s u lf u r ic a c id and 30 ml. of w ater.

The s o lu tio n was made

a lk a lin e , e x tra c te d w ith two 50 ml, p o rtio n s of e th e r , and th e e x tr a c ts d rie d over potassium hydroxide. yellow liq u id (X I), nfp =

D i s t i l l a t i o n gave 5 g . of a pale

1.5200, b .p . l6 4 -6 8 °/8 mm.

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A c i t r a t e p r e c ip ita te d from e th e r and r e c r y s ta lliz e d from d io x an e-eth er o . o gave fin e w hite c r y s ta ls , so ften in g a t 104 and m elting a t 108-110 . A nal, Calcd. f o r C ^H ^N gC y Found:

C, 58.70;

H, 7 .88;

C, 59.15;

H, 7.97;

N, 6,57.

N, 6 .8 4 .

S y n th esis o f a-m eth y l- C -d ieth y lam in o b u ty lan ilin e (X I). Follow ing th e procedure d escrib ed in d e t a i l in Bergmann's 5 p a te n t, a n ilin e and noval ketone were tr e a te d w ith hydrogen in th e presence of Raney n ic k e l.

No tr a c e o f th e d e s ire d product could be

is o la te d . Ten grams o f n o v al bromide ( b .p . 90-92°/18 mm.) was reflu x ed fo r 48 hours with 25 g . of a n ilin e , th e s o lu tio n made a lk a lin e w ith 10$ sodium hydroxide and th e bases e x tra c te d w ith e th e r.

The s o lu tio n

was d rie d over magnesium s u lf a te , so lv en t removed, and th e re sid u e f r a c tio n a te d .

Two and sev en /te n th s grams of d e s ire d product was ob­

ta in e d , b .p . 160°/10 mm.

Shiho^ r e p o rts a b o ilin g p o in t of 1 7 4 -6 °/l4 mm. o I t s c i t r a t e m elted a t 108-110 , and gave no depression on mixed m elting p o in t d eterm ination w ith th e c i t r a t e obtained above. I d e n tif ic a tio n o f th e secondary h a lid e formed i n th e rin g opening. F ifte e n grams of th e a c id -in so lu b le m ixture (V.II and IX) remain­ ing a f t e r removal o f X was d isso lv ed in 100 nil. of ab so lu te e th a n o l to

which 3*5 g . of potassium hydroxide (0.06 m ol., 20$ excess) had been added, and th e s o lu tio n reflu x ed f o r 1 1/2 h o u rs.

I t was th en cooled

to complete p r e c ip ita tio n of potassium bromide, th e s a l t f i l t e r e d o ff, and th e s o lu tio n taken to dryness under vacuum.

F if ty ml. of w ater

was added to d isso lv e th e s o lid th a t had sep arated , and th e o i l e x tra c te d

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-2 4 -

w it h two 25 m l. p o rtio n s of e th e r.

A fte r drying over magnesium s u lf a te

and removing th e so lv e n t, 12.5 g. of an orange-brown o i l rem ained. I t was d isso lv e d in 150 ml. o f ab so lu te a lc o h o l, 0 .2 g. of platinum oxide added, and th e double bond reduced in an Adams shaker under 30 pounds p ressu re of hydrogen. m inutes.

R eduction was complete in 45

The c a ta ly s t was f i l t e r e d o f f, so lv en t evaporated, and th e

re s id u a l o i l reflu x e d fo r 18 hours w ith 25 g . of s u lf u r ic a c id and 60 ml. o f w ater to remove th e cyano group.

D i s t i l l a t i o n through a 6 inch

Vigreaux y ield ed 7 g. of a c o lo rle s s liq u id , b .p . 137-9°/20 mm., 25 np - 1«5256. T his p roduct i s n -e m y la n ilin e . A t o s y l d e riv a tiv e prepared by th e Sbhotten-Baumann method and r e c r y s ta lliz e d from

95

% eth an o l sep arated in f in e w hite n eed les m elting

a t 70-72°. Anal. Calcd. fo r CigHg^NSOgJ Found: C, 68.08;

H, 7*06;

C, 68.17;

H, 7.26;

N, 4 .3 2 .

N, 4 .5 9 .

An o x a la te p r e c ip ita te d from e th e r and r e c r y s ta lliz e d

from

dioxane formed clumps of fin e w hite needles m eltin g a t 142-3°. Anal. Calcd. f o r C-^H^NO^: Found: C, 61.45;

H, 7 .1 9 ;

C,61.66;

H, 7*52;

N,5.54.

N, 5.57.

An a u th e n tic sample o f n -am y lan ilin e prepared by a lk y la tin g a n ilin e w ith O pp amyl bromide b o ile d a t 260-1 . R a d c liffe and G rindley (22)

L. R a d c liffe and R. G rindley, J . Soc. Dyers and C o lo u rists , 40, 290 (1924).

r e p o rt a b o ilin g p o in t of 260-2°.

I t s o x alate m elted a t 141.5-143°»

i t s to s y l d e riv a tiv e a t 71-3° and mixed m elting p o in ts w ith th e corresponding compounds above showed no d e p ressio n .

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

-25-

To be c e r ta in th a t th e same type of re a c tio n occurred when sta n n ic c h lo rid e was used as a c a ta ly s t, th e product rem aining a f t e r tre a tm e n t of 1- jd- chiorophenyl-2-m eth y lp y rro lid in e w ith cyanogen bromide in th e p resence of sta n n ic ch lo rid e was worked up as d escrib ed p rev io u sly .

A fte r treatm en t w ith diethylam ine and se p a ra tio n of th e

r e s u ltin g acidr-soluble f r a c tio n , th e resid u e was dehydrohalogenated, reduced, and hydrolyzed.

A sm all amount of yellow -orange o i l was ob­

ta in e d from which th e a d d itio n of an e th e r so lu tio n of o x a lic a c id p r e c ip ita te d an escalate.

R e c ry s ta lliz a tio n from dio x an e-eth er gave o m icroscopic w hite n e e d le s, m .p. 143-50.5 • N -am yl-jo-chloroaniline f o r comparison purposes was prepared by th e a lk y la tio n of £ -c h lo ro a n ilin e w ith n-amyl bromide.

A s o lu tio n

o f 25 g. of £ -c h lo ro a n ilin e and 15 g . o f n-amyl bromide (2 :1 r a tio ) i n 75 m l. of b u ty l c e llo so lv e was re flu x e d fo r 24 h o u rs.

Most of th e

s o lv e n t was removed in vacuo, 10$ a l k a l i added, and th e o i l which se p a ra te d e x tra c te d w ith 4-50 m l. p o rtio n s of e th e r .

The s o lu tio n

was d rie d overm agnesium s u lf a te , and d i s t i l l e d through a 6” ja c k e te d . o. V igreaux. The f r a c tio n which b o ile d from 143-160 /12 mm. was r e o 25 d i s t i l l e d , giving a product b o ilin g a t 152 /1 2 mu., n^ = 1,5444. A nal. C alcd. f o r C-pH^ N C l: Found:

C, 67.00;

H, 8 .1 0 ;

C, 66.83 j

H, S.IO j

N, 7.09.

N, 7 .1 1 .

I t s o x a la te , p r e c ip ita te d from an e th e r s o lu tio n by th e a d d itio n of an e th e r s o lu tio n of o x a lic a c id , m elted a t 149-51°* mixed m e ltin g o p o in t w ith th e above compound, 148-51 . Iso u re a form ation.

Base c a ta ly z e d .

In one ru n , th e m a te ria l being dehydrohalogenated was not worked

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-2 6 -

up f o r s e v e ra l h o urs, and th e product, in s te a d o f th e expected n e u tr a l cyanamide, was found to be com pletely b a s ic .

I t d i s t i l l e d a t about

152°/12 mm., a c o lo r le s s , mobile liq u id w ith a f a i n t l y ammoniacal odor, n£5,5 = 1.5214. S ix and f iv e /te n th s grams was d isso lv ed in 150 ml. o f ab so lu te e th a n o l, 0 .2 g . of platinum oxide added, and th e s o lu tio n hydrogenated i n an Adams shaker*

Reduction was complete in 10 m inutes.

The product

d i s t i l l e d a t 1 4 8 -5 0 ° /ll mm., nj)5,5 ■ 1.5088. A nal. Calcd. f o r C ^ H ^ ^ O : Found:

C, 72.20;

H, 9 .1 2 ;

C, 71.80J

H, 9.42j

N, 11.92.

N, 11.98.

Acid h y d ro ly sis gave n -am y la n ilin e, id e n ti f i e d as th e to s y la te . To show more c le a r ly what was tak in g place in t h i s re a c tio n , i t was f u r th e r in v e s tig a te d , u sin g th e more r e a d ily a v a ila b le e th y lphenylcyanamide.

This compound was prepared by adding 0 .5 mol of

e th y l a n ilin e to 0.25 mol o f cyanogen bromide in 250 m l. o f e th e r, f i l t e r i n g o f f the e th y la n ilin e hydrobromide a f t e r a h a lf hour, and washing th e e th e r la y e r w ith % hydro ch lo ric a c id to remove any unreacted b ase.

S olvent was th e n removed. When th e cyanamide was allow ed to stan d a t room tem perature

in an a lc o h o lic s o lu tio n f o r two weeks, no re a c tio n to o k p la c e , but when 1/10 eq u iv a le n t o f potassium hydroxide was added, th e e n tir e sub­ stan ce was converted o v ern ig h t in to an a c id -so lu b le product.

Solvent

was removed and th e r e s id u a l m a te ria l taken up in e th e r , leav in g a sm all amount of re s id u e .

Hydrogen c h lo rid e gas was passed in to th e

e th e r s o lu tio n p r e c ip ita tin g w hite n eedles which sep arated i n c lu s te r s , m .p. 111-2° dec. a f t e r r e c r y s t a l l i z a t i o n from 1 :1 e th an o l-d io x a n e.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

The

-2 7 -

ana l y t i c a l r e s u l t s a re i n clo se agreement w ith th o se c a lc u la te d f o r the h y drochloride o f th e pseudourea. A nal. Calcd. f o r C-q H -^ O C I: Found:

C, 57.87;

H, 7 .3 7 ;

C, 57.90;

H, 7.46;

N, 12.28.

N, 12.20.

R eaction of 6-m ethoxy-8-(2t-m ethylpyrrolidinyl)«-quinoline (XIV) w ith cyanogen bromide. A.

In E th e r.

A s o lu tio n of 10.0 g. o f th e p y rro lid in e and 9

g . of cyanogen bromide (10C$ excess) in 100 ml. o f e th e r was reflu x e d f o r th r e e hours and th e n allowed to sta n d over n ig h t.

The s o lu tio n

was decanted from th e d ark brown gummy re sid u e , and th e so lv en t and excess cyanogen bromide removed under w ater pump vacuum.

The residue

was tak en up ag ain in 150 ml, o f e th e r , forming a yellow s o lu tio n t h a t darkened r a p id ly .

The so lv en t was ag ain removed, th e resid u e

now d isso lv e d in 100 m l. of hexane, tr e a te d w ith N o rite , and cooled in th e r e f r ig e r a to r f o r th re e days. Dark yellow c r y s ta ls weighing 3*52 g . were obtained, also 3 .4 g . o f a brown v isco u s o i l a f t e r removal o f so lv e n t, which was id e n t i f i e d a s unreacted s ta r t i n g m a te ria l by th e appearance and m elting p o in t of i t s p ic r a te .

A fte r s e v e ra l r e c r y s ta lliz a tio n s from hexane,

th e product was obtain ed in th e form of sh o rt yellow prism s, m .p. 95-98 d e c ., and gave th e c o rre c t a n a ly s is f o r a bromo d e riv a tiv e o f th e s t a r t i n g m a te ria l. A nal. C alcd. f o r C15H17N2OBr: Br, 24.92; B.

Found:

C, 56.27;

In Benzene.

H, 5.32;

C, 56.08; N, 8.85;

H, 5.30;

N, 8 .7 2 ;

Br, 24.61.

A s o lu tio n of 7.5 g. of th e p y rro lid in e and

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

o

-2 8 -

7 g. o f cyanogen bromide (100$ excess) in 75 ml, of benzene was re flu x e d f o r 2 hours, and th e solvent th en removed under vacuum.

The resid u e was

e x tra c te d w ith 125 ml. of hexane, then w ith 6-50 ml* p o rtio n s of ether* The combined e x tr a c ts were evaporated to 25 ml. and cooled, y ie ld in g 2 .6 g . o f p ro d u ct.

This was tak en up ag ain in 40 ml. of e th e r, hexane

added u n t i l th e s o lu tio n became cloudy, and th e f la s k then r e f r ig e r a te d . Two ty p e s of c r y s ta ls were formed: one, yellow-brown n e e d le s, th e f i r s t t o p r e c i p i ta te , r a th e r f lu f f y c r y s ta ls which did not s ti c k to th e f la s k when th e s o lu tio n was swirled} and th e o th e r, s im ila r in appearance to th e product o f th e re a c tio n in e th e r, which stuck to th e f la s k ,

A

m oderately s u c c e ssfu l se p a ra tio n was achieved by m echanical means, th e s h o rt prism s proving, as suspected, to be id e n tic a l w ith th e compound formed in e th e r s o lu tio n .

The le s s so lu b le p o rtio n was r e c r y s ta lliz e d

fo u r tim es from 10-90 benzene-hexane s o lu tio n , giving s h o rt, narrow, o yellow prism s, m .p. 140-142 dec. Another b atch , from ethanol-hexane, o gave l i g h t yellow p l a t e l e t s , m .p. 138.5-141 dec. I t s a n a ly s is corresponded t o th e s u b s titu tio n of a cyano group in th e m olecule. Anal. Calcd. fo r C^H^N^O: Found:

C, 71.74J

H, 6.14;

C, 71.98}

H, 6.37}

N, 15.73*

N, 15.54.

Brom ination o f XIV. To a s o lu tio n of 0 .3 g . (0.00125 mol) o f XIV in 10 m l. of g l a c i a l a c e tic a c id was added a l l a t once 0 .2 g . of brbmine ( th e o r e ti­ c a l amount) in 15 m l. o f g l a c i a l a c e tic a c id . but th e r e was no p r e c ip ita tio n . poured in to 150 m l, o f w ater.

The s o lu tio n tu rn ed red ,

A fte r standing fo r 15 m inutes i t was A yellow o i l sep arated , and slow ly

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-2 9 -

s o lid ifie d ,

I t was e x tra c te d w ith 3-30 m l. p o rtio n s of e th e r , th e

e th e r s o lu tio n d rie d over potassium carbonate, th e solvent removed, and th e re sid u e ta k en up i n 30 m l. of hexane, charcoaled, and cooled, o y ie ld in g 0.11 g. o f yellow c r y s ta ls , m .p. 94«5-97 d e c ., mixed m.p. w ith XV, 9 4 .0 -9 7 .5 ° dec. O xidation of the oyano d e r iv a tiv e . To 150 m l. o f w ater in a 250 ml. round-bottom ed f l a s k equipped w ith s t i r r e r and r e f lu x condenser was added 0 .6 g. of th e cyano com­ pound, 3 g* o f potassium carb o n ate, and 10 g. of potassium permanganate in sm all p o rtio n s during a p erio d o f 8 h o u rs.

The s o lu tio n was cooled,

th e excess permanganate destroyed by adding sodium b is u l f i t e and th e p r e c ip ita te d manganese dioxide f i l t e r e d o f f .

I t was washed w ith 100

m l. o f hot w ater, th e combined f i l t r a t e s a c id if ie d w ith h y drochloric a c id to a pH of about 3» and th e s o lu tio n concentrated to 50 ml.

F if ty

m l. o f a 12# s o lu tio n o f copper a c e ta te was added, and th e s o lu tio n warmed on th e steam b a th f o r two hours, then co o led .

The l i g h t b lu e -

green p r e c ip ita te was f i l t e r e d o f f , suspended in 200 m l. o f w ater, and hydrogen s u lfid e passed in to p r e c ip ita te th e copper.

The f i l t r a t e

was th en taken t o dryness, and sin ce th e w hite s o lid resid u e was p a r tly in o rg a n ic , th e q u in o lin ic a c id was e s te r i f i e d by bubbling dry hydrogen c h lo rid e in to a re flu x in g suspension in 100 m l. of a b so lu te methanol f o r two hours, and re flu x in g f o r another two h o u rs.

S olvent was re ­

moved, 25 m l. o f w ater added, th e s o lu tio n made a lk a lin e w ith potassium carbonate and e x tra c te d w ith e th e r .

The e x tr a c t was d rie d over magnesium

s u lf a te , th e e th e r removed, and th e resid u e r e c r y s ta lliz e d from a sm all

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-3 0 -

o amount o f petroleum e th e r, g iv ing w hite c r y s ta ls , m .p. 52-3.5 . (23)

E ngler

C. E n g ler, B e r., 27, 1787 (1894).

o re p o rts 53-4 .

Summary 1.

The re a c tio n o f cyanogen bromide w ith a s e r ie s o f

N a ry l-2 -m e th y lp y rro lid in e s has been stu d ied , and th e d ire c tio n o f r in g opening shown to v a ry w ith changes in b a s ic ity o f th e n itro g e n . 2.

Another example has been found of th e re a c tio n of cyanogen

bromide p rim a rily as a brom inating a g e n t. 3.

Iso u rea form ation was shown to be c a taly zed by a l k a l i .

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23

-3 1 -

PART I I :

THE SYNTHESIS OF SOME GUANIDINO AMINO ACIDS

In tro d u c tio n

The search fo r s y n th e tic hypoglycemic agents i s s t i l l a m atter o f im portance to th e organic chem ist d e sp ite th e e ffic a c y o f in s u lin in th e tre atm e n t of d ia b e te s .

Even p resen t day p u r if ie d p rep aratio n s

o f the p a n c re a tic hormone cause a p ro te in re a c tio n in some p a tie n ts which may prevent them from u sin g in s u lin , and i t s method o f adm inis­ t r a t i o n , namely subcutaneous in je c tio n , i s o b jectio n ab le from s e v e ra l p o in ts of view .

Furtherm ore, i t i s expected th a t in a very few y ears

th e sh a rp ly in c re a sin g demand w i ll exceed th e r e l a t iv e l y unchanging supply.

For th e s e reaso n s, th e n , i t would be d e s ira b le t o fin d a syn­

t h e t i c s u b s titu te fo r i n s u lin . Almost from th e f i r s t , sy n th e tic s tu d ie s have cen tered on 24 guanidine d e r iv a tiv e s . Watanabe1s s tu d ie s (24) C.K. Watanabe, J . B io l. Chenu. 33, 253 (1918). o f th e change in blood sugar content r e s u ltin g from removal of para­ th y ro id le d him t o conclude t h a t th e r e s u ltin g hypoglycemia might be due to the concom itant in c re a se in blood guanidine.

This work, th e r e ­

fo re , le d t o th e in v e s tig a tio n of guanidine d e riv a tiv e s as in a u lin s u b s titu te s .

Guanidine compounds, as f o r example g a le g in e , have been

iso la te d * ^ (25) G. T anret, B u ll, Soc. Chim. , 35, 404 (1924)*

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-32.

h3 °s

H

> = c - c h 2- n = c

h^c

sm 2 nh2

from p la n t e x tr a c ts showing hypoglycemic a c t i v i t y .

In s u lin i t s e l f can

be considered a guanidine d e riv a tiv e , sin ce i t co n ta in s la rg e amounts 26 of a r g in in e . Wiener (26) W iener, Orvosok Lap.1a Nepegeszsegugy. £ 4 413 (1947) as re p o rte d in J . J . Lewis, P h y sio l. Rev. , 29, 75 (1949). has re p o rte d th e is o la tio n of a new hormone which he c a l l s para in s u lin , r e la te d to guanidine, and playing an im portant p a rt in carbohydrate metabolism, b u t d e t a i l s o f t h i s work a re not a v a ila b le . The p re p aratio n o f a s e rie s of guanidine d e riv a tiv e s (not described in th e l i t e r a t u r e ) culm inated in th e development of s y n th a lin ,

27

(27) E« Frank, N aturw issenschaften, .15, 213 (1927)5 E. Frank. U* N othmann, and A. Wagner, K lin . Wochschr. . J i , 2100 (1926). and s h o rtly th e r e a f te r , n e o sy n th a lin ,

28

(28) E. Frank, M. Nothmann, and A. Wagner, ib id . , 7» 1996 (1928). dodecamethylene d ig u an id in e.

Although th e s e compounds were w idely h a ile d

as in s u lin s u b s titu te s , th e lowering of th e blood sugar which th e y b rin g 29 about r e s u l t s from a to x ic e f f e c t, (29) H. Staub and 0 . Kung, ib id . . J , 1365 (1928). and prolonged a d m in istra tio n lead s to se rio u s kidney and l i v e r damage. The v a r ie ty o f guanidines prepared and te s te d since th e i n t r o ­ duction of th e sy n th a lin s i s to o numerous to m ention, and t h e i r behavior

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-33-

s u f f i c i e n t ly e r r a t i c so th a t few g e n e ra liz a tio n s may be made*

In a

com parative study of guanidine d e riv a tiv e s B isch o ff, Sahyun and Long

30

(30) F. B isch o ff, M. Sahyun, and M.L. Long, J . B io l, Chem, , 81, 325 (1929). found t h a t t o x ic ity roughly p a r a lle le d hypoglycemic a c t i v i t y .

Basic

d e riv a tiv e s w ith long a lip h a tic side chains are th e most a c tiv e .

The

s u b s titu tio n of negative groups reduced o r elim in ates e n tir e ly both th e t o x i c i t y and th e hypoglycemic a c t i v i t y .

Both guanidine formic

a c id and guanidine a c e tic a c id , fo r example, a r e n o n -to x ic in doses o f 100 mg ./k ilo g ra m and a lso not a c tiv e . D espite th e se r e s u l t s , guanidine compounds s t i l l o f fe r a f e r ­ t i l e f i e l d f o r study, b u t i t is apparent th a t a r a d ic a lly new approach i s in d icated * None o f th e many guanidine compounds h ereto fo re stu d ied have in clu d ed amino a c id s and p o ly p ep tid es.

Even though amino ac id s them­

se lv e s and simple polypeptides are devoid of hypoglycemic a c t i v i t y in f a c t , even th e m ild est h ydrolysis of th e in s u lin m olecule r e s u lts in alm ost complete lo s s of potency -

31

(31) A.M. F ish e r and D.A. S c o tt, J . B io l. Chem. , 106, 289 (1934). i t i s f e l t th a t th e combination of a guanidine nucleus w ith s u ita b le b u ild in g blocks of th e in s u lin m olecule o ffe rs th e most promising l i n e o f a tta c k .

Although amino a c id s d isp la y no hypoglycemic a c t i v i t y , 32 re c e n t experim ents (32) J.M. J o h lin , P roc. Soc. Exp. B io l. & Med., 70, 425 (1949).

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i n d i c a t e t h a t a d m i n i s t r a t i o n o f some am ino a c i d s may e n h a n c e t h e e f f e c t o f i n s u l i n , t h e r e b y c u t t i n g dovm on t h e d o s a g e r e q u i r e d . U n t i l r e c e n t l y , no b i o l o g i c a l l y a c t i v e p r o t e i n w as known t h a t r e t a i n e d i t s p h y s i o l o g i c a l p o te n c y a f t e r p a r t i a l h y d r o l y s i s , b u t t h e i s o l a t i o n o f a r e l a t i v e l y s im p le u n i t c o n t a i n i n g t h e a c t i v e p r i n c i p l e o f a com plex m o le c u le i s now a d i s t i n c t p o s s i b i l i t y . m e n ts

R ecent e x p e ri-

33

(33) Choh Hao L i , S c i e n t i f i c A m e ric a n . O c t. 1 9 5 0 , p . 2 2 . i n d i c a t e t h a t ACTH, t h e a d r e n o c o r t i c o t r o p i c horm one, i s n o t o n ly s t a b l e t o h e a t a n d a c i d h y d r o l y s i s b u t t h a t i t s a c t i v i t y r e s i d e s i n a p e p ti d e m ix tu r e c o n t a i n i n g a n a v e r a g e o f o n l y 8 am ino a c id 3 a n d h a v in g a m o le­ c u l a r w e ig h t o f 1 2 0 0 , a s a g a i n s t 2 0 ,0 0 0 f o r t h e o r i g i n a l j p r o t e i n .

It

i s e n t i r e l y p o s s i b l e , t h e r e f o r e , t h a t a c o m p a r a t i v e l y s im p le m o le c u le w i t h t h e a c t i v i t y o f i n s u l i n may y e t b e d e v e lo p e d , p e rh a p s i n a p e p ­ t i d e a n t a g o n i s t t o t h e ACTH p r i n c i p l e , f o r t h e a d m i n i s t r a t i o n o f t h i s horm one p r o d u c e s a te m p o r a r y d i a b e t e s .

D is c u ss io n

S in c e c y c l i c g u a n id i n e s h a d n o t b e e n p r e v i o u s l y t e s t e d , t h e p r e p a r a t i o n o f c y c l i c g u a n id i n e s c o u p le d w i t h r e p r e s e n t a t i v e am ino a c i d s was t h e r e f o r e u n d e r t a k e n .

S t a r t i n g m a t e r i a l s w e re b ro m o a lk y l

cy an am id es o b t a i n e d b y r i n g o p e n in g o f s u b s t i t u t e d e th y l e n im in e s w i t h c y a n o g e n b ro m id e .

T h e s e h a d b e e n f o u n d t o r e a c t s m o o th ly

1

w ith

p r im a ry a l k y l a m in e s a c c o r d in g t o th e f o ll o w i n g schem e t o g iv e g u a n i­ d in e s i n good y i e l d .

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

-3 5 -

C ^— JX2

CH — OH,

v ------------ *■

!?

BrCN

in ,

RNH2

*

W

*

V

* * « NH

CN XIX

, HBr

XX N -Butylethylenim ine m s prepared according to th e method of Wanker,

34

(34) H. Wenker, J . Am. Chem. S oc.,

CH2-CH2 X N t

R P-Bromoethylbutylcyanamide (XIX) i s a m oderately s ta b le m a te ria l b u t on standing f o r s e v e ra l weeks i s g ra d u a lly transform ed in to an e th e r in so lu b le w ate r-so lu b le compound containing io n ic halogen.

This substance

does n o t sep a ra te from s o lu tio n u n less e th e r i s added, but Y-bromopropyl b u ty l cyanamide d ep o sits w hite cubic c r y s ta ls of a substance th a t was

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-3 6 -

shown to be id e n tic a l w ith th e hydrobromide of 2 -im in o -3 -b u ty lte tra h y d ro 1 ,3-oxazine (XXIII)*

I t s form ation probably ta k e s p lace by th e fo llo w in g

ro u te : C, H-N-CH ~CH -CH -Br 4 9 i 2 2 2 GN

c4h9n- ch2- ch2- ch2oh

CN

XXI

C4H9 - \

+ HBr

xn i

C Tin— it .HBr NH

XXIII

The compound was sy n th esize d by p assin g gaseous hydrogen bromide in to an e th e re a l s o lu tio n o f Y -hydroxypropylbutylcyanam ide. c4h9- nh2

♦

cich 2- ch2- ch2oh

c4h9nch2ch2ch2 oh

BrCN

*■ C^H9-N-CH2-CH2-CH20H CN HBr XXIII

S im ila rly , th e compound from p-bromoethylbutylcyanaraide was shown to be 2-im ino~3~butyl o x az o lid in e . C4H9“N“ CH2-CH2-Br CN

H2° ° 4 V V ° ♦HBr II NH XXIV

A p a te n t

36

(36) B. Abramovitch, U.S. 2,443*062, June 8,1948 (C.A., 43, 252

(1949)).

d esc rib in g th e p re p a ra tio n of t h i s compound and o th e rs of th e same type from amino alc o h o ls and cyanogen h a lid e s appeared in th e l i t e r a ­ tu re a f t e r th e preceding work was com pleted. The a lk y la tio n of a lip h a tic amines by 0-bromoethylbutylcyanamide

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■37-

toform c y c lic guanidines tak e s p lace w ith explosive violence in th e absence of a so lv en t, but smoothly and in e x c e lle n t y ie ld in r e f lu x ­ ing a lc o h o l.

The corresponding a lk y la tio n o f amino a c id s t o form

guanidino a c id s , i s , on th e other hand, not a simple re a c tio n .

Free

amino a c id s cannot be used because th e y e x is t alm ost e n t i r e ly as d w itte rio n s .

37

(37) *

ch2_ c h 2 I R-N N

c

i m n*

, it

_

R

was shown to be th e case in two in s ta n c e s .

xxvm A lkaline hy d ro ly sis o f

1 ,3-di-n-butyl-2-im inoim idazD lid in e ^ gave N,N!-d ib u ty leth y len ed iam in e, ra th e r than N -butylethylenediam ine which would have been expected from XXVIII.

A lk alin e h y d ro ly sis of XXVII gave a compound which had th e

c o rre c t a n a ly s is f o r N -(butylarainoethyl) g ly c in e .

C.HJl 4 9

.N-CH.COOH 2

Ba(0H)2 -----------—

C, H„-N-CH„-CH„-N-CH„COOH 4 9 R 2 2 H 2

NH XXIX

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-4 2 -

Acid h y d ro ly sis o f th e acetone s o lu tio n remaining a f t e r separa­ tio n o f th e p ro d u ct y ie ld e d a number of compounds* E s te r form ation in t h i s re a c tio n i s to be expected, and th e amount of glycine is o la te d in ­ d ic a te d t h a t e s te r i f i c a t i o n was an im portant sid e re a c tio n . NHg-CHgCOONa + BrCHg-CHg-N-C^

—*

NH2CH 2^n22-C00CH2G 2 H22-N-C,H, j 4 9

CN

I

CN

HC1

The presence of n-butylethanolam ine was in d ic a te d by i t s c h a r a c te r is ­ t i c odor, but i t was not otherw ise id e n tif ie d . A co n sid erab le amount of th e d esired product, XXVII, which presumably had re a c te d f u r th e r a f t e r being formed, was a ls o obtained from t h i s f r a c tio n .

In some runs where not a l l th e glycine had d is ­

solved and th e re was as a r e s u l t a s li g h t excess of sodium m ethylate in th e s o lu tio n , th e e n tir e r e a c tio n product was acetone-soluble, and i t was only a f t e r a c id h y d ro ly sis t h a t any of th e d e s ire d product was o btain ed a t a l l . Two o th er substances were is o la te d , but in very sm all amounts. N -n-butylethylendiam ine, id e n tif ie d by comparison w ith an a u th e n tic sample, was obtain ed when th e s o lu tio n was made a lk a lin e .

I t s pre­

sence i s in d ic a tiv e of im idazoline form ation.

c^h9n- ch2- ch2- nh2

C^H9-N-CH2-CH2-Br t

. 2 HC1

po2“5

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-4 3 -

p-Bromoethylbutylcyanamide r e a c ts w ith sodium e th y la te t o give a b a sic p roduct in e x c e lle n t y ie ld , from which N -butylethylendiam ine i s ob­ ta in e d on a c id hydrolysis* Also is o la te d was a very sm all q u a n tity o f N -butylam inoethylg ly c in e (XXIX) which could have a r is e n from h y d ro ly sis o f XXVII. D espite th e n eg ativ e r e s u l t s obtained by Kurtz

39

in t h e

a lk y la tio n o f ly sin e-co p p e r complex in aqueous so lu tio n , t h i s t h i r d method o f p rep ara tio n was n e v e rth e le ss attem pted, and a product ob­ ta in e d i n very moderate y ie ld .

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-4 4 -

0 H -N-CH -CH -B r 4 9 , 2 2 CN

H ♦ NH -(CH ) -C 2 2 4 ,

00

,

0 0 1 o=c

''NH2 f c- ( ch2 )^- nh2 H XXXI

CHo C H -N , 4 9

CHo .N-(CH ) -8 ------ C=0 2 4 . »

I. NH

XXXII

„ o 2

\ 2 /° ;c u 0 '-NH2 CHo—CHo » * i t 0-C C (CH ) -N N-C H t 2 4 \ / ^9 H NH

CH2 C H -A 4 9 \

pH2 /

A-(CH ) -B-C00H 2 4 ,

NH

xxxni

I t was sep arate d from u n reacted ly s in e both by v ir tu e of th e s o lu b i lity of i t s copper complex in a b so lu te alcoboL (th e copper complex o f ly s in e i s in so lu b le in t h i s s o lv e n t), and by passage of an aqueous s o lu tio n of the product through A m berlite IRA-400, a s tro n g ly b a s ic ion-exchange

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-4 5 -

r e s in which absorbs ly s in e , but perm its passage of th e guanidine,

Al­

k y la tio n of th e sodium s a l t o f ly s in e , follow ed by se p a ra tio n of the d e sire d isomer a s th e copper complex proved to be somewhat more s a t i s ­ f a c to ry , and gave a p u rer product. The two most im portant methods fo r p reparing guanidines - th e a d d itio n o f ammonia o r amines t o cyanamide, and th e re a c tio n o f amines w ith O -m ethylisourea or S -m ethylisothiourea - were in v e s tig a te d b r ie f ­ ly , in s o fa r as th ey could be a p p lie d to th e type of compound under stu d y , but w ith only moderate success. Although cyanamide r e a c ts re a d ily w ith amines and t h e i r s a lt s in the follow ing manner, H2N-CN +

R-NH2 ---------

u m H » R-N-C-NH2

d is u b s titu te d cyanamides o fte n cannot be made t o re a c t a t a l l .

43

(43) H. Lecher and G. Demmler, Z. P h y sio l. Chem. , 16?, 163 (1927). The dim ethyl and d ie th y l cyanamides appear to be somewhat more re a c tiv e to amines and t h e i r 3 a lts than cyananddes co n tain in g longer a lip h a tic c h a in s, judging from t h e i r use as examples in th e p aten t l i t e r a t u r e .

44

(44) (a ) B r itis h p a te n t 297,029, S ep t. 12, 1927|jC.A., gfr 2447 (1929)3; (b) French p aten t 659*004, Aug. 14, 192S [cTaT, 5194 (1929)3; (c) H. S ch o tte , U.S. p aten t 1,795,738, MarT To, 1931 25. 2439 (1931)3; (d) H. S c h o tte , German p a te n t 514,24#, S e p t. 13, 1927 [C.A ., 21, 1263 (1927)3* For example, diethylcyanaraide is re p o rted

44d

to give N,N-diethyl~N*~

phenylguanidine when heated f o r 10 hours a t 100° w ith a m ixture of a n ilin e and a n ilin e h y d ro ch lo rid e.

Taurine was added to dim ethyl-

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-4 6 -

cyanamide by h eatin g fo r fiv e hours a t 120

o

in a sealed tu b e,

45

(45) D* Ackermann, Z. P h y sio l. Chem. , 234, 208 (1935)* b u t 1-phenyl-l-hydroxyethylam ine could not be made to add t o d i­ methyl cyanamide (46) H.C, Bhatnagar e t a l . , J . In d ia n Chem. S o c., 14, 344 (1937) [C .A ., 32, 512 (1938)]."" B utyldiethylam inobutylcyanam ide was heated w ith g ly cin e in a sea le d tube, varying th e tim e, tem p eratu re, so lv e n t, and a c id ity , b u t o nly u n reacted s ta r t i n g m a te ria ls were recovered, in a d d itio n t o a sm all amount of g ly c in e anhydride. The a d d itio n of ammonia to s u b s titu te d cyanaraides i s li k e ­ w ise a s lu g g is h r e a c tio n . C5HU -N-(CH2)4-B r CN

H eating XXXV i n a s e a le d tube f o r 18 hours

♦ HC(C00Et)2

NaOEt y

C5Hn -N-(CH2 )4-C-(C0QEt)2

NHCOCH-j

CN

xxxrv

NHCOCH^

XXXV ' NH, u CeH11-N-(CHo).-C-C00H 5 11 r , 2 4 t C=NH NHg i NH 2

H

C_H_.-N-(CH ) -C(C0CfEt)o y 11 t 2 4 t * C=NH NH(0CH3 NH•2 .

XXXVI a t 160 w ith a b u tan o l s o lu tio n of anmonia produced a guanidine, pre­ sumably XXXVI, as in d ic a te d by th e form ation of a w ine-red c o lo r w ith

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-47i n

a lk a lin e d ia c e ty l solution* (47) A, Harden and D. N o rris, J . P h y sio l», 42, 332 (1911)* ih e y ie ld vras o nly about two per c e n t, and th e product was not is o la te d . A s l i g h t l y g re a te r amount of pseudourea, produced by th e a d d itio n of b u ty l alco h o l t o th e cyanamide, was formed in th e re a c tio n . B e tte r r e s u l t s were o b tain ed when XXXV was tr e a te d w ith I rt

potassium amide i n liq u id ammonia.

D ialk y l cyanamides a re re p o rte d

(48) E.C. F ran k lin , J . Am. Chem. S oc., 55, 4912 (1933)* t o re a c t w ith potassium amide in cold liq u id ammonia w ith th e probable form ation of g u an id in es.

However th e work was in te rru p te d p r io r to

i t s com pletion and th e guanidines them selves not is o la te d , although th e potassium s a l t s were c r y s ta llin e and analyzed c o r r e c tly .

R eaction

of XXXV w ith potassium amide was com plicated by th e f a c t th a t t h i s sub­ sta n c e , an o i l , could n o t be d i s t i l l e d , and th e re fo re had to be used crude, but a guanidine which gave th e c o rre c t a n a ly sis fo r XXXVI was is o la te d . The u s u a lly smooth r e a c tio n of amines w ith S -m ethylisothiourea or O -m ethylisourea o fte n does n ot work w ith s u b s titu te d am ines, or ta k e s place in very poor yield *

49

(49) E. S ch u tte, Z. P h y sio l. Chem. . 279, 52 (1943). N ev erth eless, th e re a c tio n of th e copper complex of N-n-butylam inoeth y lg ly c in e (XXIX) was attem pted, w ith cyanamide, w ith m ethylisaurea, and w ith m e th y liso th io u re a .

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■48.

C, H„-N-CH -CH0-N

V9 ,

H

2

2

CH ~C=0

f\

2

H -\

V

0 t

t

\

0 b

C H -N-CH -CH -N. •CH -0=0 4 9 f 2 2, \ 2 i C=NH Hn\ 0 >* / * Cu NH 2 / v

9

Vt

0=C-CH _-N-CH -CH -N-C H t 4 9 H

0=C-CH-N-CH -CH -N-C H 2 2 2 i 4 9 C=NH mz H2S

C4 H9 “ ? ” CH2” CH2 “ N” CH2 " C00H

C=NH »a

In th e f i r s t case, th e copper complex and cyanamide were re flu x e d in 50$ a lc o h o lic s o lu tio n fo r eig h t h o u rs. t e s t fo r guanidine were sep arated .

Two f ra c tio n s giving a co lo r

N either was id e n tif ie d , but analy­

s is showed each to be a polymer of cyanamide. The copper complex and m eth y liso th io u rea were reflu x ed fo r s ix hours in aqueous so lu tio n but only unchanged s ta r tin g m a te ria l was ob­ ta in e d . An aqueous s o lu tio n of th e copper complex and m ethylisourea was allow ed to stan d a t room tem perature fo r th re e weeks.

E ig h th -fiv e

per cent of s t a r t i n g m a te ria l was recovered unchanged, and about of long lavender n eedles which had p re c ip ita te d from th e s o lu tio n during th e f i r s t two o r th re e days, and which analyzed approxim ately fo r a copper s a l t o f a diguanidine d e riv a tiv e .

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I t was planned to extend t h i s s e r ie s o f re a c tio n s to th e pre­ p a ra tio n of p ep tid es, using as s ta r ti n g m a te ria l (XXVII), th e guanidino a cid a v a ila b le in th e g r e a te s t q u a n tity .

However, th e d if f ic u l­

t i e s encountered in attem p tin g to p r o te c t th e imino grouping in th is compound precluded t h e i r p reparation* J u s t as th e amino groups in amino a c id s must be p ro te c te d in p ep tid e sy n th e sis p rio r to th e p re p a ra tio n of an acid c h lo rid e or a z id e , so must th e imino grouping in XXVII be masked to prevent cyc liz a tio h such as occurred during th e form ation of XXV* The most 50 w idely used procedure i s t h a t of Bergraann and Zervas (50) M. Bergmann and L. Z ervas, Ber*, jS5» 1192 (1932). in v o lv in g th e a p p lic a tio n of benzyl chloroform ate, or as i t i s commonly c a lle d , carbobenzaxy c h lo rid e .

I t s importance l i e s in th e f a c t th a t i t

was th e f i r s t p ro te c tin g group introduced t h a t could be removed by c a t­ a l y t i c hydrogenation, th u s p reventing com pletely h y d ro ly sis of th e pep­ t i d e linkage which in v a ria b ly accompanied removal of oth er p ro te c tin g gro u p s.

The carbobenzaxy group may a ls o be removed by tre atm e n t w ith 51 phosphonium iodide (51) C. H arington and T. Mead, Biochem. J*, 29, 1602 (1935)* o r w ith sodium in liq u id ammonia

52

(52) R. S if f e r d and V. du Vigneaud, J* B io l* Chemo, 105, 753 (1935)* th u s f u rth e r extending the a p p li c a b ili ty of th e method to cases where c a ta ly tic red u ctio n i s not fe a sib le *

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-5 0 -

The c h ie f disadvantage of t h i s reagent i s i t s i n s t a b i l i t y , n e c e s s ita tin g i t s p re p a ra tio n from phosgene and benzyl alco h o l each time i t i s used.

Stevens and Watanabe

53

(53) C.M. Stevens and R. Watanabe, J . Am. Chem. Soc. , 72, 725 (1950). in v e s tig a te d th e use o f a l l y l chloroform ate, a s tr u c tu r a lly analogous but s ta b le and commercially a v a ila b le compound, and found t h a t cry­ s t a l l i n e carb o ally lo x y d e riv a tiv e s of amino acid s could be prepared using e s s e n tia lly th e procedure f o r th e carbobenzoxy compounds.

How­

ever, w hile the two chemical procedures f o r th e cleavage mentioned above were s a tis f a c to r y , c a ta ly tic hydrogenation re s u lte d in s ig n i­ f ic a n t y ie ld s of th e carbopropyloxy d e r iv a tiv e , which was n o t cleav ed . A lly l chloroform ate 5U (54) We a re indebted t o th e Hooker E lectrochem ical Company fo r a sample o f t h i s m aterial* was t r i e d as th e f i r s t p ro te c tin g ag en t, and th e re a c tio n c a r rie d out using 1 , 3-di-n-butyl-2-irainoim idazo lid in e a s a model c y c lic guanidine (XX, R1 = n - b u ty l) .

R eaction was ra p id in e th e r s o lu tio n , th e hydro­

c h lo rid e of XX p r e c ip ita tin g and leav in g an e th e r-s o lu b le o i l .

Pass­

age o f hydrogen c h lo rid e gas in to th e e th e r s o lu tio n p r e c ip ita te d an o i l which could n ot be obtained c r y s ta llin e from any of th e common so lv e n ts but which d ep o sited c r y s ta ls of th e hydrochloride of XX on standing fo r s e v e ra l days.

Although t h i s re a c tio n was not pursued,

th e r e l a t iv e s t a b i l i t y of c a rb o ally lo x y versus carbobenzoxy deriva­ t i v e s would appear to m erit f u rth e r in v e s tig a tio n . The re a c tio n of aL ly l chloroform ate w ith XXVII was attem pted,

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-51-

both according to th e procedure of Stevens and Watanabe sodium hydroxide, u sing a f o u r- fo ld excess o f reag en t.

53 and in 20% In n e ith e r

case was any p r e c ip ita te o b tained on a c id if ic a tio n , and only unre­ ac te d s ta r t i n g m a te ria l was i s o la te d .

This l i n e of a tta c k was th e r e ­

fo re abandoned. R eaction w ith benzenesulfcnyl c h lo rid e gave no c r y s ta llin e d e riv a tiv e o r any o th e r id e n tif ia b le product, nor could s ta r tin g m a te ria l be is o la te d . Treatment o f th e hydrochloride of XXVII w ith th io n y l chlo rid e gave, as might be expected, a product resem bling XXV in i t s p h y sic a l p ro p e rtie s , and w ith none of th e c h a r a c te r is tic s of an a c id c h lo rid e .

E xperim ental

P re p a ra tio n o f 0-Bromoethyl-h-butylcyanamide (XIX).

This m a te ria l

was prepared by re a c tin g cyanaogen bromide w ith n-bu ty leth y len im in e, as 1 d e scrib ed by E ld e r f ie ld and Hageman. A p re fe rre d procedure f o r pre­ p arin g n -b u ty leth y len irain e, and one which g iv es sin improved y ie ld , is t h a t o f L eighton, P erk in s, and R en q u ist.

35

Two hundred and ninety-tw o

grams o f n-butylethanolam ine (2 .5 mol) was d ilu te d w ith 150 m l. of w ater, and 265 g» o f 96^ s u lf u r ic a c id (2 .5 mol) poured onto 135 g. of ic e .

The amine s o lu tio n was alow ly added t o the acid in a 1 - l i t e r

f la s k , coo lin g in an ice b a th .

The so lu tio n was then b o ile d v ig orously

under w ater pump vacuum, keeping a thermometer in the l i q u i d .

Cry­

s t a l l i z a t i o n s e t in a t about 135°» th e tem perature r is in g to 160°.

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-52-

H eating was th e n stopped, and th e f la s k cooled. The product was tra n s f e rr e d t o a 3 - l i t e r 3-necked f la s k con­ ta in in g 400 g , o f potassium hydroxide and 400 m l, o f w ater, and steam passed in u n t i l a l i t e r o f d i s t i l l a t e had been c o lle c te d .

One hundred

grams o f potassium hydroxide was added, th e s o lu tio n e x tra c te d w ith 3 200 m l, p o rtio n s o f e th e r, and the combined e x tr a c ts d ried over po tas­ sium hydroxide, potassium carbonate, and f in a lly over sodium.

The

e th e r was removed and the product d i s t i l l e d th ro u g h a 1 - f t . column packed w ith g la ss h e lic e s .

One hundred and tw enty-nine grams equiva­

le n t t o a 52$ y ie ld was obtained, b o ilin g a t 103°, P re p aratio n o f Amino Acid E s te r s , (55) E. F isc h er, B e r., ^

55 56 G lycine, ' ' ty ro s in e , y

1433 (1901).

(56) E . F isc h er, i b i d . , 39, 540 (1906). and c y stin e 57 (57) E„ F isch er and U, Suzuki, Z. P h y s io l. Chem, , 45, 405 (1905), e th y l e s te rs were prepared as t h e i r hydrochlorides by th e F isc h e r method of e s t e r i f i c a t i o n .

Glycine e s te r was lib e r a te d from i t s

hydrochloride by F is c h e r’s method b u t as might be expected from obse rv a tio n s in th e l i t e r a t u r e (58) E , Abderhalden and S. Suzuki, I b i d . , ^.76, 101 (1928); M. F rankel and E. K atch a lsk i, J . Am. Chem. S o c., 64, 2264 (1942). concerning th e r a p id ity of d ik eto p ip era zin e form ation from and poly condensation of t h i s compound, i t was found to be too unstable t o use,

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-53-

poly m erizatio n ta k in g place even before th e d i s t i l l a t i o n was completed* o Tyrosine e th y l e s te r i s a s o lid , m elting a t 109 C, and th e re fo re r e ­ l a t i v e l y s ta b le a t room tem perature* C yclic G uanidines. R eaction of Tyrosine E th y l E s te r w ith 3-Bromoethylbutylcyanamide.

A s o lu tio n of 5 g . ty ro s in e e s te r and 4»3 g. o f p-brom oethyl-

butylcyanamide (equim olecular q u a n titie s ) in 20 m l. o f a b so lu te e th a n o l wa3 refuxed fo r fo u r hours and the solvent removed under vacuum, leav­ in g a visco u s o i l .

E x tra c tio n w ith e th e r y ie ld e d a n e g lig ib le amount

o f m a te ria l, in d ic a tin g complete re a c tio n . s ta lliz e d .

The o i l could not be cry­

I t was then e x tra c te d w ith 5-50 ml* p o rtio n s o f w ater by

warming on th e steam b a th f o r fiv e m inutes and decanting th e aqueous s o lu tio n from th e in so lu b le polym eric re sid u e .

The combined aqueous

so lu tio n s were allowed to sta n d a t room tem perature f o r two ho u rs, and th e n decanted from th e sm all amount of o i l th a t had s e t t l e d to th e bottom of th e f la s k .

A ddition o f potassium carbonate p r e c ip i­

ta t e d th e fre e base XXV which was in so lu b le in e th e r b u t r e a d ily ex­ tr a c t e d w ith e th y l a c e ta te .

The so lv en t was removed on th e stean

b a th , 10 m l. of a b so lu te e th an o l and 20 ml* of e th e r added, and gaseous hydrogen ch lo rid e th en passed in to p r e c ip ita te th e hydroc h lo rid e .

I t sep a ra ted a s fin e w h ite needles, 2 .2 g ., m.p. 179-180

o

a f t e r r e c r y s t a l l i z a t i o n from a lc o h o l-e th e r. A nal. C alcd. f o r C ^ H ^ N ^ C l : Cl, 10*84*

Founds

C, 59.28}

H, 7.07}

C, 59.44} N, 12*77}

H, 6.81}

N, 13.00}

Cl, 10.96.

The same product was obtained when th e reactants were heated at 125° f o r 15 minutes Y/ithout a solvent*

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

-5 4 -

When the e th y l a c e ta te s o lu tio n o f XXV was evaporated down t o a volume of from 50-75 ®1* and allowed to co o l, w hite needle3 m eltin g a t 116*5-117° a f t e r tre a tm e n t w ith N orite and r e c r y s t a l l i ­ z a tio n from e th y l a c e ta te were o b tain ed .

I f eth an o l was used a s

th e solvent or i f any ethanol was added to th e e th y l a c e ta te , th e n o w hite p l a t e l e t s se p a ra te d m elting a t 139-140 « G rinding converted th e lower m elting in to th e higher m elting form, and both forms gave th e same h y d ro ch lo rid e. Anal. Calcd, f o r ®x6H21^3®2: Found:

C, 66,92;

H, 7 .2 8 ;

Acid H yd ro ly sis,

^ .9 0 ;

H, 7*32;

N, 14*64.

N, 14.40.

A s o lu tio n of 0 ,5 g . o f XXV in 60 m l, of

20$ h y d ro ch lo ric ac id was reflu x ed f o r th re e hours.

I t was then

evaporated to dryness in vacuo, 25 m l, o f w ater added and th e evapora­ tio n rep eated , to remove as much a s p o ssib le of th e hydrogen c h lo rid e . The re sid u e was then tak en up in 75 m l, of w ater and run during a two hour p erio d through a column o f 25 m l, a n a ly tic a l grade Am berlite IR-4B in a 50 ml. b u r e tte . w a te r.

The column was washed w ith 50 m l. o f

The aqueous s o lu tio n , now c h lo rid e -fre e , was e x tra c te d w ith

e th y l a c e ta te in o rd er to remove any unreacted s ta r t i n g m a te ria l. The s o lu tio n was ag ain taken t o dryness in vacuo, th e l a s t tr a c e s o f w ater removed w ith benzene and a b so lu te alc o h o l, th e re sid u e ex­ tr a c te d w ith s e v e ra l sm all p o rtio n s of e th y l a c e ta te , and th e n d is ­ solved in 25 m l, of b u ta n o l.

Anhydrous e th e r was added to th e p o in t

of in c ip ie n t p r e c ip ita tio n and the so lu tio n allow ed to stand f o r s ix h o u rs.

The sm all amount o f hygroscopic m a te ria l t h a t sep arated was

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55-

remove d. by c e n trifu g a tio n and discarded#

Anhydrous e th e r was again

added, w ith s c ra tc h in g , u n t i l a p r e c ip ita te began t o form, and th e s o lu tio n r e f r ig e r a te d o v ern ig h t.

Two hundred and f o r t y mg. of a

somewhat hygroscopic m ic ro c ry s ta llin e product (XXVI) was o b tain ed . o I t began to so fte n a t about 115 w ith gas ev o lu tio n , and was not 0 com pletely liq u id u n t i l th e tem perature reached 180 . A nal. Calcd, fo r Found:

C, 62.48;

C, 62.95;

H, 7 .7 6 ;

H, 7*54;

N, 13.77.

N, 13.88.

R eaction o f the Sodium S a lt o f G lycine and 3-Brom oethylbutylcyanamide.

To 70 ml. o f ab so lu te methanol in a 100 m l. round-bottomed

f la s k was added 1.15 g. of sodium (0.05 m ol).

A fter i t had d isso lv ed

com pletely, 4.15 g . of glycine (a 10$ excess) was added, and th e sus­ pension re flu x e d fo r tw enty minutes to in su re conplete re a c tio n of the g ly c in e .

The sm all excess remained undissolved.

Ten and tw o -ten th s

grams of p-bromoethylbutylcyanamide was then added, and the so lu tio n re flu x e d f o r fo u r h o u rs.

Solvent was then removed and the resid u e

e x tra c te d w ith e th e r to remove u n reacted cyanamide, 10-15$ u s u a lly being recovered.

The yellow -orange gummy resid u e was tak en up in

100 m l. of a b so lu te e th a n o l, f i l t e r e d fre e of g ly c in e , and concen­ t r a te d h y d ro ch lo ric ac id added dropwise u n t i l th e so lu tio n was d is ­ t i n c t l y a c id .

F if ty m l. of e th e r was added, and th e m ixture r e f r ig e r a ­

te d overnight to complete th e p r e c ip ita tio n of the sodium h a lid e s . A fte r removing th e inorganic s a l t s , th e so lu tio n was taken to dryness in vacuo, 100 m l. o f acetone added to th e viscous resid u e, and th e suspension shaken fo r an hour.

P a rt of th e m a te ria l g ra d u a lly d is ­

solved to give a yellow -orange s o lu tio n , leav in g a w hite c r y s ta llin e

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-5 6 -

re sid u e o f th e hydrohalides of th e d e s ire d guanidino acid , l- n - b u ty l- 2 imino-3-carboxymethylimidazoliifeie( XXVII)» The c r y s ta ls were f i l t e r e d , washed w ith aceto n e, and d isso lv ed in 50 m l. of butanol by wanning th e so lu tio n on th e steam b a th .

A fte r

co o lin g , i t was f i l t e r e d fre e o f tr a c e s of sodium c h lo rid e , evaporated to dryness in vacuo, and th e re sid u e then taken up in 200 m l. o f w ater. Passage through 45 m l. of A m berlite IR-4B fre e d th e s o lu tio n o f hydro­ gen h a lid e s g iving a m ild ly b a sic e f f lu e n t (jdH 8 -8 .5 on Hydrion p ap e r). Evaporation to dryness under w ater pump vacuum, e x tra c tio n o f th e r e s i ­ due w ith a b so lu te e th a n o l and s e p a ra tio n of th e sm all amount of in so lu ­ b le m atter, gave, a f t e r removal o f th e so lv en t, a 44$ y ie ld o f th e guanidino a c id (XXVJl),

I t was r e c r y s ta lliz e d from a butan o l-d io x an e-

e th e r m ixture, b u t was somewhat hygroscopic.

The hydrochloride was ob­

ta in e d as lu s tro u s p la te s , m.p. 194-194*5°> by suspending th e s o lid in 100 tim es i t s w eight o f aceto n e, a c id ify in g w ith co n cen trated hydro­ c h lo r ic a c id , adding e th e r u n t i l th e s o lu tio n became cloudy, and allow ­ ing i t t o stan d f o r s e v e ra l h o u rs.

I t may be r e c r y s ta lliz e d from

b u ta n o l-e th e r, but i f i t i3 heated in butanol fo r to o long a tim e, the pro d u ct can no lo n g e r be obtained in c r y s ta llin e form. Anal. Ca-lcd. f o r C ^ g N ^ C l : Found:

C, 46.11;

“H, 7.6 7 ;

C, 45.90;

H, 7*67;

N, 17.86.

N, 1 7 .8 2 .

Components of A cetone-soluble F ra c tio n .

A p o rtio n was re flu x ed

f o r e ig h t hours w ith 10 tim es i t s volume of 20$ h y d ro ch lo ric a c id , and th e a cid removed in vacuo.

P a rt of th e resid u e was made a l k a l i n e .

There was a stro n g sm ell o f ammonia and th e c h a r a c te r is tic odor of NbutylethanolaraLne.

The aLkaline s o lu tio n was e x tra c te d w ith e th e r,

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“57-

th e e th e r so lu tio n d rie d over magnesium s u lf a te , and hydrogen ch lo rid e gas passed i n .

The hydrochloride of N -butylethanolaraine, which i s a

hygroscopic s a l t somewhat so lu b le in e th e r, did n ot p r e c ip ita te , but a sm all amount of a w hite p r e c ip ita te was obtained, which gave sm all lu s tro u s l e a f l e t s upon r e c r y s t a ll iz a tio n from acetone-dioxane, m elting o a t 233”233*5 . I t s a n a ly s is corresponded to th e dihydrochloride of N~ b u ty leth y len ed iam in e. Anal. Calcd. fo r C^H^NgGlgj Found:

C, 38.28;

H, 9.46;

C, 38.10;

H, 9.53;

N, 14.82.

N, 14.62.

King and M cM illan^ (59) J . King and F. McMillan, J . Am. Chem. S oc., 68, 1774 (1946). re p o rt a m elting p o in t of 231-2

o

fo r t h i s compound.

An a u th e n tic sample

was prepared f o r comparison purposes by re flu x in g an e th a n o lic s o lu tio n o f b u ty l bromide w ith fo u r tim es th e th e o r e tic a l amount of e th y lan ed i1 amine, removing the so lv en t through a Vigreaux column, pouring th e r e s i ­ due in to a c o n cen trated potassium hydroxide so lu tio n , and se p a ra tin g th e upper la y e r.

A fte r i t was d rie d over potassium hydroxide i t was d is ­

t i l l e d through a 2 f t . column packed w ith g la ss h e lic e s , g iving a p ro o duct b o ilin g a t 171-2 . A hydrochloride prepared by passing hydrogen o c h lo rid e in to an e th e r s o lu tio n m elted a t 231-2 and gave no depression on mixed m eltin g p o in t d eterm ination w ith th e product obtained above. The remainder of th e a c id h y d ro ly sate, ab o u t 15 grams, was d isso lv ed in 400 m l. of w ater and s t i r r e d fo r a h a lf hour w ith 12 grams o f s ilv e r o x id e.

The s o lu tio n was f i l t e r e d , hydrogen s u lf id e passed in

t o p r e c ip ita te th e remaining s ilv e r , th e so lu tio n warmed on th e steam b ath to coagulate th e s u lfid e and f i l t e r e d w ith th e a i d o f c e l i t s .

It

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-5 8 -

was then evaporated to dryness in vacuo, removing th e l a s t tra c e s of w ater w ith benzene.

The resid u e was refluxed fo r tw enty m inutes w ith

200 ml* o f ab so lu te a lc o h o l, cooled, and f i l t e r e d , y ield in g 1*2 g . of a s o lid , w hite n eed les upon r e c r y s ta lliz a tio n from 80$ acetone, d ark 0 o ening a t 239 and m elting w ith decom position a t 248-9 . A cety latio n o ,o gave w hite c r y s ta ls , darkening a t 190 and m elting a t 204.5-206 . The m elting point did not depress when mixed w ith an a u th e n tic sample of a c e ty lg ly c in e prepared a s follow s:

0.5 g. of g ly c in e , 4 cc. o f g la c ia l

a c e tic a c id , and 1 cc. o f a c e tic anhydride were warmed over a fre e flame u n t i l th e g ly cin e disso lved, and the s o lu tio n th en q u ick ly cooled. Approximately one minute was re q u ire d fo r the r e a c tio n .

C ry sta ls of

a c e ty lg ly c in e sep arated on standing, and were f i l t e r e d and washed w ith e th e r. Comparison o f th e m elting p o in t of th e recovered g ly cin e, above, w ith m elting p o in ts recorded in th e l i t e r a t u r e i l l u s t r a t e how l i t t l e s ig n ific a n c e one can a tta c h in th e amino a c id s e r ie s to an otherw ise im portant p h y sic a l c o n s ta n t.

The follow ing m elting p oints were found

in a cu rso ry search of th e l i t e r a t u r e : 225-230° j 2 3 3 ° j darkening 228°, m.p, 232-236°j darkening 228°, m*p« 236-239°J darkening 228°, m.p. 262°; 233-236 °; 240° j 246° as th e low est accep tab le fo r pure g l y c i n e ; ^

(60) W. Anslow and H. King, Qrg. Syn. . C o ll. V ol. I , 298. and a v a r ia tio n depending on th e number of r e c r y s ta lliz a tio n s of a sample t h a t a t th e o u tse t was a n a ly tic a lly pure, from darkened a t 220°, melted a t 240°, to darkened a t 240°, m elted a t 2 5 6 ° ,^ (61) H. King and A. Palm er, Biochem. J . , 14» 582 (1920).

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The alco h o l s o lu tio n rem aining a f t e r removal of th e g ly cin e was evaporated to dryness, 150 m l. acetone added, and then concentrated hy­ d ro c h lo ric a c id u n t i l th e s o lu tio n was d i s t i n c t l y a c id ic .

A fter shak­

in g f o r o n e -h alf hour, th e w hite p r e c ip ita te was f i l t e r e d o f f , tra n s ­ f e rr e d to a 100 m l. f la s k , and warmed w ith 60 ml* o f b u tan o l. th e s o lid d isso lv ed r a p id ly . o f w hite c r y s ta llin e re s id u e .

Most of

The s o lu tio n was f i l t e r e d , le a v in g 0 .8 g« Anhydrous e th e r was added to th e f i l ­

t r a t e , u n t i l i t became cloudy, and th e so lu tio n r e f r ig e r a te d o v ern ig h t. o S ix and e ig h t/te n th s grsuns of w hite c r y s ta ls , m.p. 193-5 » were obtained, id e n t i c a l w ith th e hydrochloride of XXVII, the d e s ire d product of th e a l k y la tio n . A nal. Found:

Calcd. fo r C ^ g N ^ C l :

C, 45.73;

H, 7 .7 8 ;

C, 45.90;

H, 7 .6 7 ;

N, 17.86.

N, 17.84.

The b u ta n o l-in s o lu b le s o lid was dissolved in 15 m l. of w ater, made stro n g ly a c id w ith c o n ce n trated hydrochloric a c id ( i f an excess o f hyd ro ch lo ric acid i s n o t p resen t, a pure product i s n ot o b tain ed ), and an eq u al volume of eth an o l added. gavewhite lu s tro u s

R e frig e ra tio n fo r two hours

c r y s ta ls , m.p* 215-217°, xvhich had a s a tis f a c to r y

a n a ly s is (A) f o r th e dih y d ro ch loride of N -n-butylam inoethylglycine (XXIX). A nal. Found:

(A)

Calcd. fo r CgH^NgOgCl^ C, 38.81;

H, 8.1 9 ;

C, 38.87;

N, 10.99;

(B)

H, 8 .0 9 ; C, 39.00;

N, 11.34. H, 8.32;

N, 11.50. This compound was also prepared by th e a lk a lin e hy d ro ly sis of XXVII.

One gram was re flu x e d fo r 18 hours w ith 50 m l. o f a s a tu ra te d

barium hydroxide s o lu tio n , and th e barium then p r e c ip ita te d by th e

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a d d itio n of a s l i g h t excess of 5% s u lf u r ic a c id .

S u lfa te was removed

by passage th ro u g h a 30 ml* column of Am berlite IR-4B, th e s o lu tio n a c id if ie d w ith h y d ro ch lo ric a c id and taken to dryness.

The s o lid was

r e c r y s ta lliz e d from 9 5 % eth an o l, forming w hite c r y s ta ls m elting a t o . 214-215 • I t s a n a ly s is (E) was a ls o s a tis f a c to r y fo r the dihydro­ c h lo rid e of N -n-butylandnoethylglycine, A lk y latio n of th e Popper Complex of L ysine. used in th e se experim ents was prepared by making a s o lu tio n s li g h t l y a lk a lin e w ith

1 0

The copper hydroxide 5

% copper s u lf a te

% sodium hydroxide, and washing th e

g reen ish -b lu e p r e c ip ita te by d ecan tatio n f o r two days.

I t was then

s to re d in a stoppered b o t t l e . A so lu tio n of 3»0 g. ly s in e monohydrochloride (0,0165 mole) in 75 m l. of w ater was s ti r r e d f o r 15 minutes w ith 3 g» of s il v e r oxide to remove h a lid e io n , th e s o lid s f i l t e r e d o f f , and th e r e s id u a l s ilv e r p r e c ip ita te d by bubbling hydrogen s u lf id e in to th e s o lu tio n .

The solu­

tio n was f i l t e r e d and evaporated to h a lf volume to remove th e hydrogen s u lf id e .

About 40 ml, of th e copper hydroxide suspension was added,

th e m ixture warmed on th e steam b ath fo r 15 m inutes, and then s t i r r e d f o r a h a lf hour.

The s o lu tio n , now a deep b lu e c o lo r, was f i l t e r e d

f re e of excess copper hydroxide, evaporated t o 40 ml* in vacuo, and 80 ml* 95$ethanol was added.

Although th e so lu tio n s t i l l re ta in e d

i t s deep blue co lo r th e a d d itio n of alc o h o l caused th e p r e c ip ita tio n of a la rg e p a r t o f th e copper complex.

Three and f iv e /te n th s grams of

p-bromoethylbutylcyanamide (0*017 mol) was added and th e s o lu tio n re ­ flu x e d .

At the end o f fiv e hours i t had tu rn ed a g reen ish -b lu e , and

most of th e s o lid had gone in to s o lu tio n .

R efluxing was continued

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f o r s ix te e n hours a t which time th e s o lu tio n was colored a sea-greens The a lco h o l was now d i s t i l l e d o ff and th e s o lu tio n e x tra c te d w ith e th e r , giv in g 0»6 g. recovered s t a r tin g m aterial#

I t was th e n taken to

dryness in vacuo, and e x tra c te d w ith 5-50 m l, p o rtio n s of a b so lu te eth an o l, g iv in g a deep green s o lu tio n . in a b so lu te a lc o h o l.

The copper complex o f ly sin e i s n o t soluble

The alc o h o l was removed in vacuo,' 100 ml# of w ater

and 5 ml* of 1C$ h y d ro ch lo ric a c id added, and th e copper p r e c ip ita te d by p assin g hydrogen s u lfid e in to th e s o lu tio n .

I t was then evaporated to

h a lf volume in vacuo to remove th e l a s t tra c e s o f hydrogen s u lf id e , 40 m l. o f 20$ h y d ro ch lo ric a c id added, and the s o lu tio n reflu x e d f o r th re e ho u rs.

Excess a c id was removed a s com pletely as p o ssib le by evaporation

to dryness, th e resid u e d isso lv ed in 150 ml. of w ater, and the s o lu tio n run du rin g a th re e hour p erio d through 50 m l. of Am berlite IRA-400, a s tro n g ly b asic ion-exchange r e s in which w ill q u a n tita tiv e ly remove ly ­ sin e and l e s s b a sic amino a c id s from so lu tio n , b ut which allow s th e passage of amino a c id s more b a sic th a n ly s in e .

The column was washed

w ith 50 m l. of d i s t i l l e d w ater and th e combined e f flu e n ts taken to dry­ n ess in vacuo.

The yellow -orange viscous resid u e was e x tra c te d s e v e ra l

tim es w ith sm all p o rtio n s of acetone, d isso lv ed in 25 ml# o f ab so lu te e th a n o l, tr e a te d w ith N o rite , a c id if ie d w ith con cen trated h y drochloric ac id , tr e a te d w ith N o rite ag ain , and f in a l l y evaporated to dryness, adding s e v e ra l sm all p o rtio n s of a lco h o l and f i n a l l y benzene to remove th e l a s t tra c e s of w ater and excess a c id .

One hundred ml. of d rie d ace­

tone was added, poured o f f a f t e r s i x hours, and anhydrous e th e r added. A fte r a week the s o li d was c e n trifu g e d and d rie d a t 80° in vacuo.

The

p ro d u ct, somewhat o ff-w h ite in c o lo r, was extrem ely hygroscopic, and i t

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was d i f f i c u l t t o o b tain a com pletely s a tis f a c to r y a n a ly s is .

However a

s li g h t l y b e t t e r product was o b tained using th e procedure describ ed in th e next s e c tio n . th e A lk y latio n o f Sodium S a lt of L ysine.

To a s o lu tio n of 1.15 g.

o f sodium (0,05 mol) in 50 m l, o f a b so lu te eth an o l was added 4*57 g . of lysiriPmonohydrochloride (0,025 m ol). s a l t p r e c ip ita te d .

The so lu tio n became m ilky, b ut no

Five and o n e /te n th s grams of XIX (0,025 mol) and an

a d d itio n a l 15 ml* o f eth an o l were added, and th e s o lu tio n re flu x e d f o r fo u r h o u rs.

U ndissolved s o lid s were removed by c e n trifu g in g , so lv e n t

evaporated o ff in vacuo, and th e viscous re sid u e e x tra c te d w ith th re e 50 m l, p o rtio n s of e th e r .

I t was th e n d isso lv ed in 75 ml, o f ab so lu te

e th an o l, a c id if ie d w ith co n cen trated h y drochloric a c id , and a f t e r r e ­ f r ig e r a tin g f o r two h o urs, th e inorganic p r e c ip ita te f i l t e r e d o f f . S olvent was removed in vacuo, 75 m l, o f b u tan o l added to d isso lv e th e re s id u e , and th e s o lu tio n f i l t e r e d f r e e of a sm all amount o f r e s id u a l in o rg a n ic m a tte r.

Butanol was th en removed in vacuo.

The re sid u e did

n o t c r y s ta lliz e on long stan d in g under e th e r, nor was i t a t a l l so lu b le in acetone, as was th e case w ith th e glycine d e riv a tiv e . I t was d isso lv ed in 100 m l, of w ater, s ti r r e d f o r a h a lf hour w ith an excess of copper hydroxide suspension, f i l t e r e d , and th e solu­ t i o n tak en down t o d ryness.

The resid u e was e x tra c te d w ith ab so lu te

a lc o h o l as d escrib ed in th e preceding s e c tio n , and th e product ob­ ta in e d in th e same way.

In t h i s case, tre atm e n t w ith A m berlite IRA.-400

gave a c o lo rle s s e f f lu e n t, but the c h a r a c te r is tic s of th e f i n a l p ro d u ct, i t s c o lo r and h y g ro sco p icity , were about th e same as t h a t o f th e m aterial o b tain ed p re v io u sly .

The substance had to be d rie d very c a r e f u lly ju s t

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p r io r to a n a ly s is .

The ch lo rid e a n a ly s is rep o rted below i s from a sample

n o t so d rie d , and i s estim ated from o th er a n a ly tic a l data t o be about % o to o low . M.P. 110-140 dec. Anal. C alcd. f o r C l, 20.65.

Founds

C, 45.07;

C» H, 7 .9 0 ;

45.4&J H, 8.16;

N, 16.49;

N, 16*32;

C l, 19.94.

S ynthesis o f N -isoam yl-W -(£-carboxy-l-am ino-n-aniyl)guanidine. Iso am y lp y rro lld in e was obtained by warming a m ixture of 150 g . o f 1 ,4 d ich lo ro b u tan e (1*18 mol) and 220 g . (2 .5 mol) o f isoamylamine in a 1 - l i t e r f la s k on th e steam b ath f o r 16 hours.

Heat o f re a c tio n kept

th e s o lu tio n re flu x in g v ig o ro u sly f o r an hour, but th e re a c tio n th e n slow ly subsided.

An excess of 10$ sodium hydroxide was added, th e solu­

ti o n shaken, and th e su pernatant s e p a ra te d .

I t was d rie d over potassium

hydroxide and d i s t i l l e d , g iving 102 g. b o ilin g a t 168-70®, a y ie ld of 62 61.5/6. I t has been rep o rte d (62)

M. R ubinshtein and G. Menshikov, J . Gen. Chem. (U .S .S .R .) 14* 161 (1944). “ ~-

a s b o ilin g a t 166-7°• Qmega-bromobutyliao amyl cyanamide, XXXIV, was formed by th e re ­ a c tio n o f cyanogen bromide on isoam ylpyrrolidine in e th e r s o lu tio n , in a manner analogous to t h a t d escrib ed in P a rt I .

A crude y ie ld o f 83$

was ob tain ed , but o nly about h a l f of th is rra te r ia l d i s t i l l e d , th e re ­ m ainder r e s in if y in g i n th e d i s t i l l a t i o n f la s k .

The product was a co lo r­

le s s liq u id , b .p . 140° / o . 5 mm. To a s o lu tio n o f 2 .3 g. of sodium (0 .1 m ol)in 100 m l. of ab so lu te

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e th a n o l d rie d over magnesium e th y la te was added 21.7 g . of acetam idom alonic e s te r (0 .1 m ol), and a f t e r s o lu tio n was complete, 28 g . (10$ excess) o f XXXIV.

The s o lu tio n was re flu x e d f o r fo u r hours, cooled,

and th e s a l t which had p r e c ip ita te d during th e re a c tio n was f i l t e r e d o ff.

Solvent was then removed in vacuo, 100 m l. of 10$ hydrochloric

a c id added, and th e m ixture was shaken w e ll and e x tra c te d w ith fo u r 50 m l. p o rtio n s o f e th e r .

The combined e x tr a c ts

were d rie d over mag­

nesium s u lf a te , and th e so lv en t removed, leav in g 32.2 g . of a re d d ish orange viscous o i l , XXXV, a y ie ld of 84$.

Seven grams o f an a c id -so lu b le

f r a c tio n was a ls o is o la te d , b u t was d iscard ed . Four grams o f crude XXXV was heated in a sealed tube fo r fo u ro te e n hours a t 150 w ith 50 ml# o f b u tan o l containing 4 g* of ammonia. The a c id -so lu b le m a te ria l r e s u ltin g was re flu x e d f o r s ix hours w ith 50 m l. o f 10$ hydro ch lo ric a c id , taken t o dryness, d isso lv ed in 100 m l. o f w ater and run through 30 m l. of Am berlite IRA-400, washing the r e s in w ith an a d d itio n a l 150 m l. o f w ater.

Upon evaporation to dryness and

e x tra c tio n w ith a b so lu te a lc o h o l, a w hite c r y s ta llin e re sid u e , 0.24 g. a f t e r r e c r y s t a l l i z a t i o n from 90$ e th a n o l, m.p. 260-4° dec. rem ained.

Its

a n a ly s is corresponded to th e monohydrochloride o f omega-N-isoamyllysine. A nal. C alcd. f o r C-jjH^NgOgCli Found:

C, 52.15;

H, 9.70;

C, 52.25;

H, 9#97j

N, 1 1.08.

N, 11.1 3 .

The m a te ria l in th e alco h o l e x tr a c t, 0.07 g .» which gave a co lo r t e s t f o r a g u anidine, was a c c id e n ta lly l o s t , and in view o f th e b e t t e r re ­ s u lt s o b tain ed in th e fo llo w in g experim ent, t h i s run was n o t re p e a te d . Approximately 150 m l. o f liq u id ammonia was added to 3*9 g . o f potassium (0 .1 mol) and one sq. cm. of ru s ty w ire gauze in a 200 m l.

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3-necked f la s k f i t t e d w ith a m ercury-sealed s t i r r e r and a i r condenser w ith a tta c h e d drying tu b e .

A fter 15 m inutes, when th e in te n se blue

c o lo r of th e potassium had com pletely disappeared, 8 g . of XXXV (0*02 mol) was added through a dropping fu n n el.

The o i l appeared to

s o lid if y , b u t ra p id ly re a c te d , forming a w hite p r e c ip ita te .

S tir r in g

was continued fo r four h o u rs, w ith no co o lin g other th an th a t pro­ vided by th e slow ev ap o ratio n of th e ammonia, and 5*3 g, (0 ,1 mol) ammonium c h lo rid e then added to n e u tr a liz e th e potassium .

When evapora­

tio n of th e ammonia was complete, th e s o lid residue was e x tra c te d w ith 200 m l, o f a b so lu te a lc o h o l, leav in g 7 .9 g. o f in o rg a n ic re s id u e . e x tr a c t gave a stro n g c o lo r t e s t w ith d ia c e ty l.

The

A fte r removal of s o l­

v e n t, th e resid u e was re flu x e d f o r e ig h t hours w ith 100 m l, of 20# hy4d ro c h lo ric a c id , th e s o lu tio n taken to dryness, d isso lv ed in 250 ml. o f w ater, and run through 100 ml. of A m berlite IRA-400.

An equal

volume o f w ater was used to wash th e column, and th e combined e f flu e n ts taken to d ry n ess.

Only a b a s ic o i l was obtain ed .

T his was red isso lv e d

in 125 m l, o f w ater and p assed through 30 ml* of A m berlite IRA-400 once a g a in .

The column was now washed w ith 250 ml. of w a te r, but t h i s tim e

th e washings were taken to dryness s e p a ra te ly , y ie ld in g 0.38 g. o f a w hite s o lid which decomposes on ra p id h e a tin g from 50-80°,

I t s analy­

s i s corresponds to t h a t o f th e d e s ire d guanidine, XXXVI, w ith perhaps a s lig h t contam ination by th e corresponding u re a . Anal. Calcd. fo r 0-j^i26N4 °2 } C* 55.31; Found:

C, 55.66;

H, 10.02;

H, 10.08;

N, 21.70.

N, 20.93.

Iso u re a Formation: a c id c a ta ly z e d .

Conversion of B-Bromoethyl-

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butylcyanand.de to 2 -B u ty l-3 -im ino-oxazolidine.

The discovery of io n ic

halogen in a sample of XIX t h a t had been standing f o r s e v e ra l months le d t o an in v e s tig a tio n of t h i s substance.

Upon th e a d d itio n of e th e r

about h a lf th e m a te ria l se p a ra te d a s a w a ter-so lu b le gummy s o lid .

How­

ever Y-bromopropylbutylcyanamide d ep o sited w hite cubic c r y s ta ls on stan d in g , so i t was in v e s tig a te d f i r s t .

The c r y s ta ls were powdered,

washed w ith e th e r to remove occluded cyanamide, and r e c r y s ta lliz e d from 9:1 dio x an e-eth an o l t o give a w hite c r y s ta l lin e product, m.p. o 156-7 . When an aqueous s o lu tio n was made a lk a lin e , a b asic o i l sep a rated which could be e x tra c te d w ith e t h e r .

Passage o f gaseous

hydrogen bromide in to an e th e r s o lu tio n gave th e same hydrobromide. Anal. Calcd. fo r CgH-^y^QBr: Br, 33.78.

Found:

C, 40.56;

An o x a la te m elted a t 1 2 6-8°.

C, 40*50;

H, 7 .09;

H, 7«17>

N, 11.92;

N, 11.82;

Br, 34.12.

R efluxing w ith 20$ sodium hydroxide fo r

tw elve hours gave a base which was p r e c ip ita te d from e th e r as i t s o x a la te , m .p. 145-6°, and which gave no depression on mixed m elting p o in t d eterm in atio n w ith an a u th e n tic sample o f an o x alate of b u ty lam inopropanol. A nal. Calcd. f o r C ^-^N C y Found:

C, 49.05;

H, 8 .6 8 ;

C, 48.87;

H, 8.59;

N, 6.33*

N, 6,16.

ButylamLnopropanol was prepared by warming two raols of b u ty lamine w ith one mol trim eth y len echlorohydrin in a 1 -1 . f la s k on th e steam b a th . subsided.

There was a vigorous re a c tio n a f t e r te n minutes which soon A fte r two ho u rs, an excess of 4Q£ sodium hydroxide was added,

th e a lk a lin e s o lu tio n e x tra c te d w ith e th e r, th e e x tr a c t d rie d over o potassium carbonate and th en d i s t i l l e d , the product b o ilin g a t 115-120 /2 0 mm. f

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A s o lu tio n of 5*2 g . of butylaminopropanol in 50 ml* of a b so lu te eth a n o l was added to 4«3 g* o f cyanogen bromide (equim olecular q u a n ti­ t i e s ) i n 50 ml* o f ab so lu te e th an o l, and th e s o lu tio n allow ed to sta n d f o r f i f t e e n m inutes w ithout coo ling, although considerable heat was gen erated .

Solvent was d i s t i l l e d o f f , and th e resid u e e x tra c te d w ith

e th e r to remove u n reacted amino a lc o h o l, giving 0*3 g .

The resid u e was

tr e a t e d w ith aqueous a l k a l i , e x tra c te d w ith 30 ml. of e th e r, and d rie d over potassium carbonate.

Tw enty-five m l. o f iioxane was added, and

gaseous hydrogen bromide blown over th e su rface r e s u ltin g in an immedi­ a te c r y s ta llin e p r e c ip ita te .

R e c ry s ta lliz a tio n from dioxane-ethanol

gave 6 .3 g . of a product which m elted a t 157-157.5°,mixed m elting p o in t o w ith th e substance o btained above, 156.5-157*5 • In th e same way, th e m a te ria l o b tain ed from XIX was r e c r y s ta lliz e d from ethanol-dioxane, g iving sm all w hite cubic c r y s ta ls , m#p. 130-1°*

Ex­

tr a c tio n o f th e base and r e p re c ip ita tio n as th e hydrochloride gave c r y s ta ls o 36 o m elting a t 145.5-147 . Abramovitch re p o rts a m elting p o in t of 145-7 • I t s sy n th esis was c a rrie d out from butylam inoethanol and cyanogen bromide a s d escrib ed in th e preceding paragraph, o r else in e th e r e a l so lu tio n using in t h i s case tw ice th e th e o r e tic a l amount of amino a lc o h o l.

The

hydrobromide of th e amino a lc o h o l p r e c ip ita te d , leav in g th e cyanamido a lc o h o l i n s o lu tio n .

Gaseous hydrogen ch lo rid e produced an immediate

p r e c ip ita te of th e hydrochloride of 2 -b u ty l-3 -im in o -o x azo lid in e.

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Sumaary

1*-

C yclic guanidine d e riv a tiv e s of some amino a c id s have

been prepared.

2 .-

The a p p lic a tio n of methods of guanidine sy n th esis to

s u b s titu te d d ia lk y l cyanamides has been stu d ie d .

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V ita M ilton Green was "born in Boston, M assachusetts in 1920. A fter atten d in g the p u b lic sc h o o ls in that c i t y , he entered the M assachusetts I n s t i t u t e of technology in 1936 and was graduated w ith the degree of S.B, in Chemistry in 1940.

He

then entered the f i e l d of in d u s t r ia l resea rch , holding p o s i­ t io n s w ith se v e r a l pharmaceutical companies.

In June 1944

hiB p r o fe s s io n a l career was interrupted by a tour of duty with the E i r s t Marine D iv is io n which included se r v ic e in the Solomons, Okinawa, and China,

fo llo w in g h is discharge in

August 1946, he again obtained an in d u s t r ia l p o s it io n , but resigned to begin graduate s tu d ie s a t Columbia U n iv e r sity in September 1947. t io n s :

He i s a co-author o f the fo llo w in g p u b lic a ­

"The Absorption and D istr ib u tio n o f In su lin la b e lle d

w ith R adioactive Iodine", S cie n c e, 96., 362 (1942); "Electro­ p h o retic Components of Globin", J . B i o l . Chem., 1 4 6 . 583 (1942); and "Toxic E f f e c t s of Some Basic P ro tein s" , Proo. Soe, Exp, B io l, and Med. , 5jD, 70 (1942).

He i s a member

o f the American Chemical S o c ie ty , Phi lambda U p silon , and Signa X i.

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ABSTRACT o f D is s e rta tio n Subm itted by:

M ilton Groen May 1951

P a rt I - The Von Braun Cyanogen Bromide R eaction: I I : N-Aryl P y rro lid in e s .

A pplication to

The re a c tio n o f para s u b s titu te d 1-phenyl-2-m ethyl p y rro lid in e s w ith cyanogen bromide, in which th e para s u b s titu e n ts were hydrogen, methoxyl, and c h lo rin e , was s tu d ie d in s e v e ra l so lv e n ts.

Two

ring-opened isom ers were o b tain ed , th e g r e a te r amount o f opening tak in g place a t th e seoondary carbon to give 4-bromoamyl phenyl cyanamide and varying amounts of o le f in derived from t h i s substance, and about 20$ o f opening a t th e primary carbon t o give 1-mathyl-4-brom obutyl phenyl cyanamide. A p o ssib le ex p lan ation fo r th e d iffe re n c e in th e q u a n tity o f isom ers obtained in th e re a c tio n of N-phenyl p y rro lid in e s here desoribed and N -butyl p y rro lid in e s in v e stig a te d in previous work i s discussed.

The

data obtain ed in t h i s and previous work a re c o n s is te n t w ith th e form ulation o f th e re a c tio n as tak in g place by a quaternary s a l t type of in term ed iate such a s t h a t form ulated o r ig in a lly by von Braun follow ed by simultaneous f i r s t and seoond ord er displacem ents by bromide on th e quaternary complex. These Mata appear to in d ic a te fu rth e r t h a t the decreased b a s ic ity o f th e n itro g e n caused by s u b s titu tio n of a phenyl fo r an a lk y l group fav o rs th e io n is a tio n re a c tio n over the second order displacem ent, thereby causing th e form ation of in creased amounts of secondary h a lid e . 6-M ethoxy-8-(2, -m e th y lp y rro lid in y l)q u in o lin e rea c te d w ith cyanogen bromide to in tro d u ce a bromine s u b s titu e n t in th e 5- p o s itio n , n e ith e r a tta c k a t th e q u in o lin e n itro g en n o r opening o f th e p y rro lid in e

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- M. Green

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ABSTRACT -

r in g ta k in g p la ce .

Under come co n d itio n a both t h i s isomer and one

co n tain in g a cyano s u b s titu e n t were formed. B art I I - The S ynthesis of Some Guanidino Amino Acids. A s e r ie s of c y c lic guanidino d e riv a tiv e s of amino acid s have been prepared fo r te s tin g as p o ssib le hypoglycemic a g e n ts. (3-Broinoethyl b u ty l cyanamide, formed by th e re a c tio n of cyanogen bro­ mide on n-butylethylenim lne was tr e a te d w ith an amino a c id e s te r , a sodium s a lt and a copper complex.

R eaction w ith ty ro s in e e th y l e s te r

formed an im idaz-im ldazole, converted upon a c id liydrolysis in to th e h ydroohloride o f th e guanidino a c id , a -L l-n -b u ty l-2 -im in o -3 -im id a z o lid yl]-p -(p -h y d ro x y p h en y l)-p ro p ionic a c id , obtained fre e of i t s s a l t by passage o f an uqueous so lu tio n through a column of A nfrrlite IR-4B. R eaction with th e sodium s a l t of gly cin e formed th e d esired l-n-butyl-2-iiaino-3-C ttrboxym ethyl ira id a z o lid in e . I t was shown t h a t in th ese two cases a t l e a s t , th e re a c tio n ta k e s place as form ulated r a th e r th an by a d d itio n across th e cyano group follow ed by displacem ent of bromide t o form th e isom eric im id azo lin e. R eaction w ith th e copper complex o f ly s in e presumably a ls o formed th e corresponding iraid azo lid in e, b u t the product was n o t obtained a n a ly tic a lly pure.

However, use of th e sodium s a lt o f ly s in e gave a sub­

stance w ith accep tab le a n a ly tic a l v alu es.

The stro n g ly b a s ic ion exchange

r e s i n Am berlite IRA-400 was used t o sep arate t h i s product from unreacted ly s in e . The prep aratio n o f open-chain guanidine d e riv a tiv e s of amino a c id s from d ia lk y l amines and d ia lk y l cyanamides was a ls o in v e s ti­

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ABSTRACT

g ate d .

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- M. Green

Although th e se compounds a re g e n e ra lly u n reactiv e under con­

d itio n s norreally used fo r guanidine sy n th e sis, potassium amide in liq u id ammonia s o lu tio n was found to re a c t to form a guanidine.

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