Studies on the Synthesis of Lysine

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P U R D U E U N IV E R S IT Y

THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION

by______________________

Durward G-eorge O'Dell

e n title d

STUDIES ON THE SYNTHESIS OF LYSINE

COMPLIES WITH THE UNIVERSITY REGULATIONS ON GRADUATION THESES

AND IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS

FOR THE DEGREE OF

rx a# . i X

PROFESSOR IN CHARGE OF THESIS

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TO THE LIBRARIAN;----IS Vvû+' THIS THESIS ggrUTOTETO BE REGARDED AS CONFIDENTIAL.

GRAD. SCHOOL FORM 9—3 -4 9 — 1M

D epa r tm en t

STUDIES ON THE SYNTHESIS OF LYSINE

A Thesis Submitted to the Faculty of Purdue University

by

Durward George O ’Dell

In Partial Fulfillment of the Requirements for the Degree of . Doctor of Philosophy

June, 1950

ProQuest N um ber: 27714117

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uest ProQuest 27714117 Published by ProQuest LLC (2019). C opyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C o d e M icroform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346

AOKNOWLHDGMENT Sincere appreciation Is extended to Professor Ed. F. Degerlng for his capable guidance, friendly encourage­ ment , and helpful adtlce which were so willingly given:-dur­ ing these studies. The author wishes to acknowledge the financial aid provided by The National Institute of Health which sup­ ported this work through a predootoral research fellowship.

TABLE OF CONTENTS Page ABSTRACT..............

1

INTRODUCTION........................

1

DISCUSSION..............................................

11

REAGENTS USED...........................................

20

EXPERIMENTAL.........................................

22

Preparation of 1,5-Dlchloropentane..................

22

Preparation of € -Chlorooapronltrile...............

23

Preparation of € -Chlorocaoronltrile.

.....

24

Preparation of € -Chlorooaproio Acid.

..........

26

Preparation of e-Chloro- ec-bromocapro 1c Acid.......

27

Preparation of Lysine Using Aqueous Ammonia.........

28

Attempted Preparation of Lysine Using Anhydrous Ammonia.....................

29

Attempted Preparation of Lysine Using Potassium Phthalimlde..........................

30

Preparation of 1 ,5-Dibromopentane..........

30

Preparation of G -Bromocapronitrile.

.......

31

Preparation of € -Bromocanroic Acid. ...............

32

Preparation of Ammonium Hydrogen Adlpate............

32

Preparation of Adipamic Acid........................

33

Attempted Dehydration of Adipamic Acid with Thionyl Chloride. ................................

34

Attempted Dehydration of Adipamic Acid with Calcium Carbide...................

34

Attempted Dehydration of Adipamic Acid with Phosphorus Pent oxide..............................

35

Preparation of f-Chlorovaleronltrlle..........

35

TABLE OF CONTENTS (Cont. ) Page Preparation of jg.-Chlorovaleronitrile........

36

Preparation of

37

6 -Chlorovalerlo Aoid........

Attempted Preparation of

8 -Cyanovaleric Acid

38

Reaction of Benzoic Acid with Adiponitrile..........

39

Preparation of Pimelonltrile........................

39

Preparation of Pimelonltrile....

40

......

.....................

4l

Preparation of Ammonium HydrogenPlmelate............

41

Preparation of Pimelic Acid.

Preparation of Plmelamlc Acid.

.........

42 .....

43

Preparation of

€ -Amino caoronit ri le..................

44

Preparation of

€ -Benzoylaminocapronitrile...........

44

Preparation of JS-BenzoylaminocaproicAcid.

Attempted Bromlnation of € -Benzovlaminocapro nit rile........... BIBLIOGRAPHY........... VITA........ ......................... ..................

45 46

(Contribution front the Department of Chemistry, Purdue University)

STUDIES ON THE SYNTHESIS OF LYSINE (l) (1)

From the Ph. D. Thesis of D. G. O ’Dell, Purdue Univer­ sity, June, 1950.

By Ed. F. Degering and D. G. O ’Dell AN ABSTRACT x It has already been established that in many cases amino acid mixtures may be employed clinically to great advantage. lysine.

These uses do not require large amounts of

Large tonnages of lysine could be used to improve

the biological value of bread and cereal protein.

In con­

trast with foods of animal origin it is striking that foods derived from plants are apparently deficient in lysine and tryptophane.

It is probable that lysine would also increase

the biological value of the protein present in the ration fed to most animals.

Thus, a large demand would exist for

synthetic lysine if it could be produced cheaply. Many syntheses of lysine have been published but few of these seem to be suitable for commercial production. Those which may be of commercial importance are:

the syn­

thesis of von Braun (2) with its improvement by Eck and (2)

von Braun, Ber., 42, 839 (1909)»

il

Marvel (3 ) a.nd Galet (4), the synthesis of Gaudry (5) (3)

Eck and Marvel, "Organic Syntheses11, Coll. Vol. II, John Wiley and Sons, Inc., New York, N. Y . , 1943, pp. 74, 76, 374.

(4)

Galet, THIS JOURNAL, 62,, 86 (1947).

(5)

Gaudrv. Can. J. Research. 26B, 387 (1948).

starting with dihydropyran as improved by Rogers (6) , the (6)

Rogers, THIS JOURNAL, Ü ,

1837 (1949).

synthesis of Sayles (7 ) and the synthesis of Boatright (8). . (7)

Savles and Deserinp:. ibid. . 71. 3161 (1949).

(8)

Boatright, Ph. D. Thesis, Purdue University, August, 1949.

.

During this research, several methods were investigated and some possible intermediates were prepared.

C1 (CH2)501

- - f e M ■» 01(0H2 )50N

I

II 01(0H2 )50O2H

?£?/•!■-» 01 (CHg )^OHBrOOgH

HgO III

H2N (0H2 )4 GHNH2C02H V

IV

ill

SS3-..> |h3N cGH2 )^OHKHjCOg^ *

201"

VI Compound II was prepared in yields of approximately 50$6 using either aqueous alcohol or Cellesolve as the sol­ vent •

The hydrolysis of II was achieved by use of 70%

sulfuric acid.

Yields of 85% were obtained.

Bromlnation

of III was accomplished by the Hell-Volhard-Zelinsky reaction at a temperature of 80°C. in yields of 80%*

Ammo no lysis of

IV followed by the treatment with hydrochloric acid yielded D,L-lysine dihydrochloride. Instead of the ammonolysis of the chloro derivative of caproic acid, the bromo derivative may be used.

Thus,

€ -bromocanrolc acid was prepared. Br(0Hg)gBr

Br(CH2 )5CN

VII H 3S°fr » h 2ç

VIII BrCOlWcPOgH 25 IX

Compound VIII was prepared in 50% yields using aqueous alcohol as a solvent. J0% sulfuric acid.

Hydrolysis of VIII was achieved by

Bromlnation of IV to give a c , € -dlbromo-

caproic acid may be accomplished according to the method of Merchant (9) and the ammono lysis of this compound may (9)

Merchant, et al,. , THIS JOURNAL, 42., 1828 (1927) •

Iv

be accomplished by the method of Boatright (8 ). A good method for making adipamic acid is by the action of gaseous anhydrous ammonia on a solution of adlpic acid in ethanol.

The half-ammonium salt of adlpic acid precip­

itates from the solution as soon as it is formed thereby keeping the diàmmonium salt from being formed.

The ammonium

hydrogen adlpate is easily dehydrated by heat to adipamic acid. From the corresponding nitrile, has been prepared.

8 - chlorovaleric acid

Attempts to prepare

8 -cyanovaler 1c

acid

from the chloro valeric acid gave only the lactone of Ô hydroxyvaleric acid.

The reaction of benzoic acid with

adiponitrile gave benzonitrile, but again no

Ô -c yanovaleric

acid was obtained. Adiponitrile has been partially reduced to

€ -amino-

eapronitrile with Raney nickel and hydrogen. EXPERIMENTAL Preparation of

C-Ohloro eapronitrile.— In a 2-1. three-

necked, round-bottom flask, fitted with a stirrer, a reflux condenser and a separatory funnel were placed 141.1 g. (1.0 mole) of l ,^-dlchloropentane and 350 ml. of absolute ethanol. In the separatory funnel was placed 51* 6 g. of 95^ sodium cyanide (equivalent to 1.0 mole of 100$ sodium cyanide) dissolved in 120 ml. of water.

The mixture was heated under

a reflux condenser with stirring and the cyanide solution slowly added.

This addition took three hours and the re-

V

fluxing was contInued for an additional three hours, The solution was cooled and then diluted with 400 ml* of water and the chloronitrile was extracted with a 70-ml. and then 30-ml. portion of chloroform.

The chloroform solu­

tion was washed with 200 ml. of calcium chloride solution (prepared by adding one volume of water to an equal volume of saturated solution of calcium chloride) and dried over fused calcium chloride. The dried solution was then distilled from a Clalsen flask.

The chloroform was removed by distillation at atmos­

pheric pressure until the temperature reached 120°G.

The

remainder was distilled at 3 mm. pressure and the following fractions were collected:

(l) recovered 1 ,5-dichloropentane

boiling from 50-70°C., 46.5 0** (2) _€-chloroeapronitrile boiling from 70-95°0., 46.8 g. and (3) pimelonitrile boiling from 95-l45°0., 20.5 0*

This was a yield of 53*2/6 and a

conversion of 67.0% based on 1,5-dichloropentane.

The € -

chloro eapronitrile was redistilled at 85°C. at 5 mm. Anal. Found:

Oalcd. for C6H10NC1:

0, 54.8; H, 7*66.

0, 54.7; H, 8.0.

The yield of pimelonltrile was 16.8%. No increase in yield was obtained by adding the sodium cyanide solution slowly to the dlchloropent ane instead of adding it all at the beginning of the reaction. An attempt was made to prepare •€-chloro eapronitrile in the same manner as described above only using Gellosolve as the solvent at a temperature of 120°G. for three hours.

Vi

T3aeee rèaôtion conditions were too vigorous and the reaction mixture turned black. Preparation of

The yield of nitrile was only 13- 4$.

C -Ohlorocaproic Acid. — In a 500 ml.

three-necked, round-bottom flask fitted with a water-cooled reflux condenser and a dropping funnel was placed 241.5 6of 7056 sulfuric acid (1.726 moles of 100# acid).

In the

dropping funnel was placed 113*6 g. (O.863 mole) of € ohlorocapronitrile.

The nitrile was allowed to drop slowly

into the flask which was heated with a burner.

After the

reaction started, the burner was removed and the reaction continued until all of the nitrile had been added.

At the

end of this time the mixture was refluxed for an additional ten minutes and then for thirty minutes as 200 ml. of water was added through the dropping funnel. The solution was allowed to cool and then extracted with diethyl ether in a continuous liquid-liquid extractor for eight hours; then the ether solution was separated and dried over Drierite. The dried solution was then distilled from a Claisen flask.

The ether was removed by distillation at atmospheric

pressure.

The remainder was distilled at 6 mm. and the

portion boiling between 122-125°0. was collected.

This

weighed 111.0 g. and represents a yield of 85*6#.

The pro­

duct was redistilled at 111°G. at 4 mm. Anal. Found:

Oalcd. for CÎ6II1102G1:

°> *7.8ï

-7.36.

0, 47.9; H, 7*40.

An attempt was made in a similar experiment to steam

vil

distill the Jg;-ohlorocaprolc acid from the reaction mixture. This method of isolation of the product did not prove satis­ factory. Preparation of

g-Ohloro- ^bromocaproic Acid.— In a

200-ml. round-bottom flask were placed 79*4 g. (0.527 mole) of Jg.-chloro caproic acid, 1.0 ml. of phosphorus trichloride and 28.1 ml. (0.55 mole) of bromine which had been dried by washing once with 50 ml. of concentrated sulfuric acid.

The

flask was fitted with a reflux condenser whose top was con­ nected with a trap and absorption

bottle

containingwater.

The flask was then placed in an oil bath which was kept at 75-80°0. for five hours.

The temperature was then raised

to 100oC. and kept there for two additional hours.

The

reaction mixture was cooled and then 100 ml. of water was added to hydrolyze any acyl bromide present.

Sulfur dioxide

was passed through the mixture to remove the excess bromine. The two layers were separated and 100 ml. of ether added to the organic layer. and distilled.

This was dried over Drierite, filtered,

The fraction boiling between 130-l40°0. at

3 mm. was collected and it weighed 101.1 g. which represented a 83*5# yield.

The product was redistilled at 140-142°0

at 3 mm. Anal. Found:

Oalcd. for OgH^OgOlBrî

C, 31*4; H, 4.39.

0, 31*2; H, 4.23*

After standing for two weeks the caproic acid crystallized.

€.-chloro- ^-bromo-

After six recrystallizations

from heptane, the melting point was 35^0.

Till

Anal. Found:

Oalod. for OgH1002OXBr:

0, 31.4; H, 4.39.

0, 31.3; H, 4.33-

Prenaratlon of Lvslne Using Aqueous Ammonia.— In a Erlemneyer flask was placed 53 ml. of aqueous ammonia (28.7#, sp. gr. 0.90) (0.80 mole). added 11.5 6* (0.05 mole) of

To this was

€ -chloro- ^C-bromo caproic acid,

24.0 g. (0.25 mole) of powdered ammonium carbonate and 0.2 g. of cuprous chloride.

The mixture was mixed well and trans­

ferred to a nickel autoclave whose volume was approximately 75 ml. and whose diameter was 18 mm.

The molar ratio of acid,

ammonia, and carbon dioxide was 1,26,5* The autoclave was closed and heated for 24 hours at 80°0* without shaking.

At the end of this time the auto­

clave was cooled, opened, emptied and washed with two 10ml. portions of water, the washings being added to the reac­ tion mixture.

The solution was then filtered and the residue

being inorganic was discarded.

The filtrate was evaporated

under vacuum without heating nearly to dryness.

To this

was added 15 ml. of hydrochloric acid (37-38#, sp. gr. 1.19) (0.18 mole).

This was again evaporated nearly to dryness'

under vacuum without heating. The residue was extracted with 40 ml. of alcohol and filtered while hot and the residue again extracted with 20 ml. of hot alcohol and filtered.

The filtrates were com­

bined and the residue discarded.

The filtrate was cooled to

15°0. and 75 ml. of ether was slowly added with constant stirring.

The precipitate was filtered and weighed 2.2 g.

ix

This was chiefly Inorganic. The- filtrate was.evaporated to about 40 ml. and boiled with Norite and filtered while hot.

The filtrate was cooled

and 80 ml. of ether was added with constant stirring. precipitate was filtered and weighed 2.0 g.

The

This was re-

crystallized twice by dissolving in hot alcohol and precip­ itating with ether.

The final product weighed 0.7 S* and

melted at 187-189°0., the melting point recorded in the liter­ ature for lysine dihydrochloride. A similar run was made

using the same amounts of

materials but at a temperature of 130°0. for 24

hours. Only

0.5 S* of lysine dihydrochloride was recovered. Preparation of

€ -Bromoeapronitrile.— In a 500-ml.

round-bottom flask was placed 115*0 g. (0.5 mole) of 1,5dibromopentane, 200 ml. of absolute alcohol and 20 ml. of water.

A Soxhlet extractor with a condenser was attached to

the flask and 25*8 g* of 95% sodium cyanide (equivalent to 0.5 mole of 100$ sodium cyanide) was placed in the extraction thimble.

The alcohol was re fluxed through the sodium cyanide

for twelve hours. The flask was cooled and 20 g . of anhydrous potassium carbonate was added. was filtered. Pod column.

After standing for twelve hours, this

The filtrate was distilled using a three-foot After the alcohol was distilled off, the sodium

bromide was filtered from the residue and then the residue was distilled through the same column. of 1,5-daich represents a yield of 93.7#. The yield was reduced by reducing the amount of alcohol used as the solvent.

Although adlpic acid is very soluble

in alcohol, efficient stirring of the reaction mixture could not be maintained toward the end of the experiment unless an excess of alcohol were present. Preparation of Adipamic Acid.— In a 1-1. round-bottom flask was placed 152.8 g. (0.937 mole) of ammonium hydrogen adlpate.

The flask was then placed in an oil bath and

heated at 175 ± 5°G. for three hours.

The flask was then

allowed to cool. To the flask 200 ml. of water and 2.0 g. of Norite were added.

The mixture was boiled for five minutes and

then filtered while hot to remove the Norite. was cooled in an ice bath and filtered.

The filtrate

The filtrate was

concentrated to 50 ml., cooled, and again filtered.

The

residues were combined and dried fifteen hours over sulfuric

xil

acid in a desiccator.

The adipamic acid weighed 123*5 g*

and melted from 125-130°C.

This represents a yield of 90.

Thus the yield of adipamic acid based on adipic acid was 85*Q?£. Preparation of

S -Chlorovalerlo Acid.— In a 500-ml.

three-neeked, round-bottom flask fitted with a reflux con­ denser and a dropping funnel was placed 140.2 g. (1.0 mole) of 70# sulfuric acid. 58.8 g. (0.50 mole) of

In the dropping funnel was placed g-chlorovaleronitrlle and a small

portion of the nitrile was added to the flask. was heated.

The flask

'When the reaction commenced, the heat was removed

and the nitrile added at such a rate as to keep the reaction going.

After the addition of the nitrile was completed, the

mixture was re fluxed for an additional fifteen minutes.

Then

100 ml. of water was added and the mixture was refluxed for thirty minutes longer. The mixture was cooled and extracted with ether in a continuous extractor for twelve hours.

The ether was separated

and dried over Drierite for ten hours.

The ether was distilled

off and the residue was distilled at 5 mm.

The product was

collected from 109-111°C. and weighed 35*6 g.

This represents

a yield of 52.2#. Anal. Found:

Oalcd. for C^H^OgCl:

C, 44.0; H, 6.64.

G, 44.0; H, 6.53»

Attempted Preparation of S -Cyanovaleric Acid.— In a 1-1. round-bottom flask was placed 98.0 g. (0.72 mole) of chlorovalerlo acid.

This was made just basic to phenol-

xiii

phthaleln with a solution of sodium hydroxide.

An aqueous

solution of sodium cyanide (0.80 mole) was added to this. A reflux condenser was attached to the flask, and the flask was heated with a Gias-col heating mantle.

After heating

for a few minutes the solution turned black and heating was discontinued.

The solution was then placed in a 1-1. three-

necked flask fitted with a dropping funnel and a tube to carry away the hydrogen cyanide.

Enough sulfuric acid was

added to neutralize all the sodium cyanide and sodium hydrox­ ide which had been added. The acid solution was extracted with ether and the ether extract dried over Drierite.

The Drierite was filtered

off and the ether was distilled at atmospheric pressure.

The

remainder was distilled at 5 mm. and the fraction boiling from 85-88°C. was collected.

This weighed 23*4 g.

pound was probably the lactone of

This com­

6 -hydroxyvaleric acid.

After standing for a few days, it polymerized to a solid. Approximately 10 g. of residue was left In the flask. No compound was recovered from the aqueous solution after the ether extraction. «• Reaction of Benzoic Aoid with Adiponitrile.— In a 500ml. round-bottom flask fitted with a reflux condenser were placed 122 g. (1.0 mole) of benzoic acid and 108 g. (1.0 mole) of adiponitrile.

The flask was heated in an oil bath

at 210 ♦ 5°0. for fourteen hours.

At the end of this time

the mixture was cooled and distilled at 3 mm. fractions were collected:

The following

xiv

57- 61° 133-140° 126-1279

31.4 g. 52.3 6* 56.3 g.

benzonitrile adiponitrile benzoic acid

No j£.-cyanovaleric acid could be isolated from the residue. The benzonitrile was hydrolyzed to benzoic acid.

After

recrystallization from water the melting point of the benzoic acid showed no depression when mixed with a sample of pure benzoic acid. Preparation of € -Aminoeapronitrile.— In a 375-ml. bottle was placed 56.9 ml. (0.5 mole) of adiponitrile. Five grams of Raney nickel catalyst and then 75 ml. of absolute ethanol were added.

The bottle was attached to an

Adams low-pressure hydrogenator and the temperature was ad­ justed to 65°C.

The pressure dropped from 45 to 10 psi. in

four hours. At the end of this time, the contents of the bottle were filtered.

The filtrate was distilled at atmospheric

pressure until all of the ethanol was distilled.

The re­

mainder was rectified at 2 mm. using an 18-inch column packed with glass helices, and the following fractions were collected: 3.5 20.2 21.3 6.7

g. g. 6* g*

60 to 63°0. 74 to 7690. 112 to 115°0.

Hexamethylenediamine JÊ-Aminoeapronitrile Adiponitrile Residue

This represents a yield of 58.7# of € -amino capr onit rile and a conversion of 31* 3#* Preparation of j£-3enzoylaminocapronitrile.— In a 200-ml. round-bottom flask fitted with a stirrer were placed 20.2 g.

XV

(0.183 mole) of _g^-amlno eapronitrile, 20 ml. of water, and 24.0 g. (0.6 mole) of sodiiam hydroxide dissolved In 100 ml. of water.

With constant stirring 34.6 ml. (0.3 mole) of

benzoyl chloride was added slowly. and the residue was air dried. times from 7056 ethanol.

This was recrystallized three

After drying the product weighed

26.2 g. and melted at 92-93°0. 66.5#.

The mixture was filtered

This represents a yield of

STUDIES ON THE SYNTHESIS OF LYSINE

INTRODUCTION The purpose of this Investigation is to develop a good simple synthesis for lysine.

By using low-priced, readily

available materials, it was hoped that such a synthesis, if developed, would be commercially feasible.

Lysine is one

of the amino acids which have been found to be essential for the optimum growth of certain animals and probably humans. This amino acid occurs fairly abundantly in the hydrolysis products of many proteins.

Because of the tedious and ex­

pensive procedure required for its isolation from protein hydro lysates, together with the fact that most synthetic methods available are likewise tedious and expensive, only limited use can be made of this important compound. It has already been established that in many cases amino acid mixtures may be employed clinically to great advantage. They are given parent ©rally when food cannot be taken by mouth— for example, after gastro-intestinal surgery.

They

may be given orally when normal protein digestion is im­ paired, in hypoproteinemia, or in cases where losses of body protein are abnormally high.

Amino acids have been

particularly effective in the treatment of stomach ulcers, in the maintenance of nitrogen balance after severe burns, and in the treatment of protein depletion.

Also the use of

supplementary lysine, by itself, may be of distinct value

2

as a means of improving the utilization of proteins during pregnancy and lactation*

Synthetic amino acids have been of

considerable value in the fundamental biological research on amino acid utilization since the isolation of the pure compounds from proteins is often difficult or practically impossible* The above uses would not require large tonnages of ly­ sine*

However, large quantities of lysine could be used to

improve the biological value of bread and cereal protein. In contrast with foods of animal origin, it Is striking that foods derived from plants are apparently deficient in lysine and tryptophane.

Among the foods of plant origin used for

human consumption, only the protein of the soybean approaches in lysine content the proteins of animal origin* As a group, the cereal grains provide far more protein in the world’s dietaries than any other major class of foods, even though they are deficient in lysine.

The great majority

of the world's population, however, can neither afford to produce nor buy but limited quantities of animal proteins. During recent years, plant proteins have provided about 405i of the total protein in the average diet of the people of the United States (40).

This figure is considerably

higher in many other countries of the world.

The availability

of a cheap synthetic lysine might go far to improve the world's protein supply by improving the nutritive value of cereals in which it is a limiting factor (33)• It has been shown that when corn constitutes a major

3

part of the ration of the growing pig, the addition of tryptophane gives a growth response (34).

It is probable

that lysine would also increase the biological value of the protein present in the ration fed to most animals.

Thus

a large demand would exist for synthetic lysine if it could be produced cheaply. All synthetic procedures for preparing lysine result in the formation of the D,L-mixture.

It has been generally

agreed that utilization of the D-isomer of an amino acid depends on its deamination and re amination into the L-isomer or natural isomer.

Since deaminated lysine cannot be re-

aminated, its D-form cannot be converted into the L-form and hence cannot be utilized for lysine metabolism (31) • Recently it has been found, however, that the human may be able to metabolize D-lysine (3)»

If this is true, then it

would not be necessary to prepare the pure L-lysine as the D,L-mixture could be metabolized. Relatively few satisfactory complete syntheses of lysine have been reported.

The first reported synthesis of lysine

was by Fischer and Weigert (25) who prepared this amino acid (as the picrate) in a 15♦5$ overall yield from ethyl malonate and

t -ohlorobutvonitrile as shown in the following equations: HgOfCOgEt jg * OKOHg^CH. «. EtN02/Na0Et

T

NO (CH2 )

(CO-jEt )2

p. NC(CH2 )3 *C( sNOHjCOgEt

♦ red.., then hydrolysis

■ >

lysine dlhydrochloride

4

The principal, objection to this method is the low yield (32/< of theoretical) obtained in the final reduction using sodium ande ethanol as the re duct ant.

However, Bor so ok (8)

and also Olynyk (40) have recently used this synthesis to prepare lysine with 0-14 in the epsilon position. Increased the yield in the last step to 73#*

Olynyk

This was ac­

complished by catalytic reduction using platinic oxide as the catalyst. In 1903» Sorensen (48) published a synthetic method for preparing lysine; but the reactions are far too complex to permit commercial production by this method.

The steps

involved in this synthesis are indicated by the following equations:

C6H4 «J0)2:NK «• BrOa(OOgEt)g + C1(0H2>3CH

>

---► 06H4(00)2:N.CH(002Bt)2

C6H4 (00)2:N* 0(aH2CH20H2CN)(002Efc)2

* red. then hydrolysis

---»

lysine dihydrobromide

In 1909 von Braun (51) reported a synthesis of lysine starting from N-benzoyl piperidine.

All the reactions em­

ployed were common except for the first step.

The steps

involved in the synthesis are indicated by the following equations:

SI

+ P G l ^ --- »

B z m ( G H 2 ).gCl

5~

♦ SON

BzlB(0H2)5eH

♦ h 2o /h

B z NH(CH2 )5C02H

i Brg/P

Bzra(CH2 )4CHBrC02H BzNH(CH2j^CHMHgOOgH

* “ 3 ♦ hydrolysis

lysine dlhydroohloride

This synthesis was modified by Eok and Marvel (16) who prepared e -benzovlaminooanro 1o acid from eyelohexanone and obtained lysine in an over-all yield of 23#•

Until

recently this procedure, as represented by the following equations, was the best and most convenient method for the synthesis of D,L-lysine: NOH tt + NaNO,

NaHSO-

(17)

h 2s o 4

(17)

* BzCl/NaOH

BzNH (CHg )çCOgli

(17)

; Brg/P

BzNH(0H2 )^OHBrOOgH

(18 )

* mh3

BzNH(0H2 )^OHNHgOOgH

(19)

* hydrolysis

lysine dihydrochloride

(19)

Q-aleti(28) simplified the above method by using sulfuryl chloride in the halogénation of the benaoylaminocaproic acid and proceeding via the °(-chloro acid. In contrast to \ phosphorus and bromine, sulfuryl chloride forms a homogeneous

6

solution and is far more economical*

It gives yields of

96-98#. Gayles (44) has also suggested several modifications of the existing syntheses for lysine.

One Improvement of

Eok and Marvel procedure was based upon the hydrolysis of caprolaetam with hydrochloric acid to

6 -amlnocaproic acid.

The rest of the process Is similar except the last step. The ammonolysis of ;j^-benzoylamino-JX-bromoc&proic acid was effected by the use of aqueous ammonia and ammonium carbonate in the presence of cuprous chloride with a decided increase in yield. Lysine was synthesized from acrolein by Sugasawa in 1927 (49) and the synthesis is summarized by the following equations: CH2=OHCHO + HOI + Et OH + KCN/KI

-- »

---►

-- >

4- H2

---»

HgN(GH2 )^GH(OEt )2

BzNH(0H2 )30H(0Et)2

i hydrolysis: 4- H2G(GO2H)2

01(GH2 )20H(OEfc)2

HC(CH2 )2CH(0Et)2

* red. (Na + EtOH) ir BzGl/KOH

---»

BzHH(GH2 )3OHO -- +>

BzHH(GH2 )3GH:GH002H

BzHH(GH2 )3GO2H

The rest of the synthesis was completed like that of von Braun.

This synthesis is not practical since ten steps are

required and the yields on some of these reactions are poor. The facility with which carboxyl!c acids are converted into amines, by the Schmidt method employing hydrazoic acid.

7

stimulated the development of another method for the synthesis of lysine,

Adamson (2) developed an excellent method for

preparing small amounts of lysine by starting with 2-carbethoxycyolohexanone.

This synthesis Is shown by the follow­

ing equations:

f hydrolysis ♦ HN-j

---», HOgO (GHg)jjOHHHgCOgH lysine dlhydroohloride

The over-all yield for this synthesis Is 60$.

However, the

explosive nature of hydrazoic acid prohibits the application of this reaction to produce lysine In large quantities* Foster and Schmidt (26) prepared lysine from certain protein hydrolysates by the method of electrical transport. Hydrolysis products of casein, gelatin, fibrin, and red blood cells are placed in the center compartment of a three com­ partment bakellte cell having semi-permeable walls between the compartments.

When a direct current Is passed through

the solution which Is maintained at a pH of 5*5» the amino acids separate fairly sharply into three fractions:

(l)

the predominately acidic amino acids such as aspartic, glutamic, and 2-hydroxyglutamic acid which migrate towards the anode; (2): the basic amino acids such as arginine, histidine, and lysine, which migrate towards the cathode; and (3) the monoamino monocarboxylic acids which remain in

8

the oentez* compartment •

"When the pH of the solution of the

basic amino acids is adjusted to 7*5 and electrolytic trans­ port again employed, arginine and lysine migrate to the cathode, while histidine remains in the center compartment • The method of transport was found applicable to the prepara­ tion of lysine in relatively large quantities. Cox, King and Berg (15) have prepared lysine from hydrolyzed blood corpuscle paste using a modification of Foster and Schmidt ’s method.

They used a cell of wood

const miction coated with water-proofing material.

Sulfuric

acid was added to increase the conductivity of the cell. However, much time was involved ip the filtration and washing of the barium sulfate, which was formed when sulfuric acid was used in the hydrolysis of the blood paste.

On the

whole, their yields led them to believe that the method of electrical transport was by far the most practical method for the preparation of lysine in large quantities. -Recently, several completely different syntheses for lysine have been published.

Q-audry (29) prepared lysine in

good yields from 2,3-dihydropyran.

The following equations

represent this synthesis:

HO(CH2)4,OHO

H0(aH2 )4C|^iH

*(

9

* Hfîr

" nh3

---►

—

* hydrolysis

/NH— 00 Br(GHp)A O K O H ^ O O g H

i Brg/P

— -» OKCH g ^ C H B r O O g H

13

-*•

"t;^Len HOI

---►

lysine dihydrochloride.

From 1,5-dichloropentane, the first step is to make _£-chlorocapronitrile using sodium cyanide.

The difficulty

In this reaction is to produce the chloronitrile to the exclusion of the dinitrile. (53) prepared

In 1905 von Braun and Steindorff

€ -chlorocanronltrile by heating

€ -benzoyl-

aminocapronitrile with phosphorus pentachloride. product was benzoyl nit rile. prepared the

The by­

Four years later Albert (4)

e -chloro canronitrl le from 1,5-di chloropentane

and potassium cyanide in yields of about 30%. a boiling point of 242-250°C.

He reported

In this work the chloronitrile

has been prepared in yields of better than 50% from 1,5dichloropentane using either aqueous alcohol or Oellosolve as the solvent.

The boiling point is 85°0. (5 mm.).

The prin­

cipal by-product is pimelonltrile. The addition of catalytic amounts of either sodium iodide or cuprous cyanide did not affect the yield or con­ version.

Also changing the amount of the solvent did not

increase the yield. In hydrolyzing the nitrlle to the corresponding acid, 70% sulfuric acid was used. in yields of over 85%.

This hydrolysis proceeds smoothly

Basic hydrolysis of the chloronitrile

would not have been acceptable since it would cause dehydrohalogénation to yield the unsaturated acid instead of the chloroacid. € -Chlorooanroic acid was brominated in the alpha-

14

position by the Hell-Volhard-Zelinsky reaction.

Either

catalytic amounts of red phosphorus or phosphorus trichloride were used.

The yields were better than 8056.

It should also

be easily possible to chlorinate this compound with sulfuryl chloride in the same manner that Galet (28) chlorinated benzoylamlnocaproio acid. Ammonolysis of ^(-chloro- 6-bromocanrolc acid yields lysine.

Sisler and Cheronis (4) in their studies on the

ammonolysis of halogen acids have shown the yield of the primary amino compound is profoundly affected by a change in the pH of the ammo no lytic solution.

Decreasing the ]dH

inhibits the secondary and tertiary reactions as shown by the following equation:

HgNOHROOO- + H3O*

1-- » hJnCHRCOCT * HgO

In the presence of a high concentration of hydronium ions, the equilibrium is forced to the right, covering up the free pair of electrons on the nitrogen atom, and inhibiting the secondary and tertiary restions.

Also it has been shown that

catalytic amounts of cuprous chloride increases the yield of taurine from 2-chloroethanesulfonic acid (45) •

Therefore,

in the ammonolysis of 6-chloro-2-bromocg,proic acid, ammonium carbonate and catalytic amounts of cuprous chloride were used.. However, only low yields of lysine were obtained. Since the omega-chlorine in oaproic acid was difficult to replace with an amino group, the bromo derivative was

used. Instead of the chloro derivative.

Boatright (7 ) pre­

pared lysine in a 62% yield by the ammonolysis of £$,_€dibromoeaproic acid.

A different synthesis of this inter­

mediate is shown by the following equations: H0(GH2 )50H +HBr

--- >

BrCOHgîçBr

* NaCN

;__ v

BrfOHgj^N

♦ h */h 2s o 4

►

Br(0H2 )50O2H

♦ Br2/P

>

Br(GH2 )40HBrC02H

* m 3 then HOI

-- +

lysine dihydrochloride

Again the starting material is one which may be pro­ duced from furfural.

By using %8% hydrobromic acid and

concentrated sulfuric acid, 1>5-pentanediol was converted into 1,5-dibromopentane in yields of about 80$. v _£-Bromocapronitrile has been prepared from the cor­ responding acid as shown by the following equations: Br(CH2 )5002H v S0C12 then '+ 8001g

___ y

>. Br(OH2 ) g O O m 2 .

Br(0H2 )50H

(9)

Also It has been prepared by Trunel (50) from 1,5-dibromopentane but the yields are not reported.

In this work the

bromonitrile was prepared in yields of about 50$ using sodium cyanide.

The nitrlle was hydrolyzed to the corres­

ponding acid using 70$ sulfuric acid.

This acid has also

been prepared by the oxidation of 6-bromo-l-hexanol; the action of hydrobromic acid on the lactone of _g-hydroxycaproic acid; and the hydrolysis of j£-phenoxycaproic acid

16

wltda laydrotoromic a o ld . Bromlnatlon of

-bromocaproic acid may be carried out

in accordance with the directions of Merchant (36) to give a 80# yield of _2$.,j£-dibromoeaproic acid. Since difficulty was encountered in putting in the omega-amino group of lysine by ammonolysis, a synthesis was ■> tried whereby this group would be generated by reduction. The following equations show this synthesis: HO20(0H2 )40O^H' v HH3 + heat:

"

■>' dehydrate

--- » l ^ O g C C C H g ^ C O g H > H2HOO(CH2 )4OO^Î -> NGCCHgJ^GOgH

♦ reduction

f HgNfGHgJ^OOgH

The remainder of the synthesis could be carried out by the Eck and Marvel procedure. Adipamic acid has been made from the anhydride (22) and also by the action of aqueous ammonia on methyl hydrogen adipate (32).

However» it was found that an easier method

for making this compound was by the action of gaseous anhydrous ammonia on a solution of adipic acid in ethanol.

The half­

ammonium salt of adipict-acid precipitated out of the solution as soon as it was formed thereby keeping the di ammonium salt from being formed.

The ammonium hydrogen adipate was easily

dehydrated by heat to adipamic acid.

The yield of adipamic

acid based on adipic acid was approximately 85#* Of the many attempts to dehydrate adipamic acid to fi-ovanovaleric acid, none were successful.

Best and Thorpe

17

have made this compound by the action of alkali hydroxides in alcohol solution on 2-oyano-cyelopentan-l-one (6)•

Also

the synthesis of this compound has been reported by the action of sodium cyanide on the lactone of j£.-hydroxycaproie acid (14), Another line of attack on the utilization of furfural as a source of other chemicals is the catalytic removal of the aldehyde chain to give furan followed by hydrogenation of this compound to tat rahydro furan •

Conversion of fur­

fural to furan is readily carried out by passing a mixture of furfural vapor over a catalyst consisting of a mixed chromite of zinc and either manganese or iron.

Hydrogen­

ation of furan to t et rahydro furan occurs in the presence of catalysts such as nickel. The most important of the ring opening reactions of t et rahydro furan is the use of hydrogen chloride to open the ring under vigorous reaction conditions giving 1,4-di chlorobutane as the only product,

This can be accomplished by

passing a mixture of t et rahydro furan and aqueous hydrogen chloride under 15-20 atmospheres pressure through a reactor maintained at 180°C,

With proper conditions and recycling

of by-products substantially quantitative yields of 1,4dichlorobutane are secured (10),

When large scale production

is underway, it is estimated that the price of this chemical will be in the neighborhood of 22-30 cents per pound (21)• It was believed that

S -cyanovaler 1c acid could be made from

1 ,4-diehlorobutane as shown in the following equations:

18

01 (OHg)^01 «. HaOH

-- ► OKOHgJ^ON

«■ H*/HgS04 '

►

01 (OHgj^COgH

♦ NaON

►

NO (OHg )4 ,OOgH

I

Tii© S -ohlorovaleronitrile was mad© in the same manner aaf.the

chlorooapronitrile in yields of about 45%•

This

was hydrolyzed to the corresponding acid in yields of 5Q%. Preparation of

S -cyanovaler 1 o acid has been reported by

other methods such as the hydrolysis of jg.-phenoxyvaleric acid with hydrochloric acid (27)» and by the hydrolysis of JT-chloropropylmalonic ester (35). Attempts were made to make & -cyanovaleric acid from the corresponding chloroacid# was the lactone of

The only product isolated

S -hydroxyvaleric acid#

Oolby and Dodge (13) reported that fatty nitriles reacting with aromatic acids exchange their cyano and ' carboxyl groups giving fatty acids and aromatic nitriles# Therefore an attempt was made to prepare S -ovanovaleric acid by the reaction of adiponitrile with benzoic acid. Benzonitrile was obtained but no S -cyanovalêric acid could be isolated# Since the production of jgT-cyanovaleric acid was not achieved, and since the preparation of adipamic acid was accomplished with such ease, it was thought that € -benzoyl amlnocaproic acid, an intermediate for lysine, could be synthesized as represented by the following equations:

19

OKGHgXgPl «■ NaON

N0(0H2)50N

i- H2S04

h o 2c (o h 2 )5oo 2h

;

m

■p. NH^OgO (CH2 )gOOgH

3

t- heat

*.

h 2n o c (c h 2 )5c o 2h

*- Br2/NaOH

►

h 2n (o h 2 )5o o 2h

i- CgHgdOCl -

#. OgHgCONH(OHg)5002H

Again the starting material is one tAiioh can easily be made from furfural#

Pimelonltrile has been made by the

action of potassium cyanide on 1 ,5-cLlchloropentane (ll), on 1 ,5-dlbromopentane (52)» and on 1,5-dllodopentane (30). Plmelic acid also has been prepared by many different pro­ cedures (12» 23» 42 , 37 » 47» 39),»

In this work the pimelo­

nltrile was made by the action of sodium cyanide on 1,5dichloropentane and this was hydrolyzed to plmelic acid with 70% sulfuric acid.

A yield of 50% of plmelic acid based

on 1,5-dichloropentane was obtained. It was more difficult to prepare pimelamlc acid from the half -ammonium salt than adipamic acid. was never obtained.

A pure compound

The Hoffman reaction on the impure

pimelamlc acid went in poor yields. Arbuzov and PoZhiltsova (5) reported that small amounts of adiponitrile could be reduced with large amounts of Raney nickel and hydrogen at 0.5 to 0.8 atmospheres to give €.-amino oaoronit ri le.

By using catalytic amounts of Raney

nickel at a pressure of 45 pounds per square inch and at 65°0. this reduction was run with a yield of about 60%.

20

This compound was benzoyl&ted but attempts to brominate _ê-benzoylaminocapronitrlle with sulfur were not successful• REAGENTS USED The reagents employed in this investigation are listed below together with their sources: J. T. Baker Chemical Company Acid, benzoic Acid, hydrobromic Acid, hydrochloric Acid, sulfuric Ammonium carbonate Ammonium hydroxide Sodium carbonate Sodium hydroxide Sodium iodide Carbide and Carbon Chemicals Corporation: Calcium carbide Cellosolve Central Scientific Company: Nitrobenzene OornmanAiai Solvents Corporation: Ethanol Dow Chemical Company: Chloroform E, I. du Pont de Nemours and Company: Ammonia

Adiponitrile 1 .4-Dichlorobutane .* 1, 5 -Di chloropentane* 1 .5-Pentanediol* * Generous samples of these chemicals were donated for this investigation Eastman Kodak Companys Ethyl acetate Thionyl chloride Phosphorus trichloride Potassium phthallmide Eli Lilly Company: Phosphorus pent oxide Gilman Paint and Varnish Company: Raney nickel alloy Malllnckrodt Chemical Works: Bromine Calcium chloride Ether Phosphorus pentachloride Potassium carbonate Sulfur Matheson Company, Incorporated: Sulfur dioxide Merck and Company Incorporated: Cuprous cyanide Sodium cyanide

22

Toluenes Paragon Testing Laboratories; Acid, adipic Benzoyl chloride Pennsylvania Salt Manufacturing Company: Oarbon Tetrachloride Pfanstlehl Chemical Company: Norite Virginia Gasoline and Oil Company; Petroleum Ether W. A» Hammon Priorité Companys Drierlte

EXPERIMENTAL Preparation of 1.5-Dichlorooentane *— To a mixture of 600 ge (376 ml.) of carbon tetrachloride was added 240 g. (1.15 mole) of phosphorus pentachloride.

Then 119*8 S*

(1.15 mole) of 1 ,5-pentanediol was added slowly with efficient stirring.

After the addition the reaction mixture was de­

composed with ice and the carbon tetrachloride layer separated. This was washed four times with 100 ml. portions of 20$ sodium hydroxide and dried over calcium chloride for fifteen hours. The calcium chloride was removed by filtration and the carbon tetrachloride distilled off at atmospheric pressure through a 2-foot column packed with glass helices.

The

residue was distilled at 6 mm. and the fraction boiling

23

from 57-58°0. was collected. presented a yield of 22.456.

This weighed 36.3 g. and re­ Remaining in the flask was

23.9 S* of residue. Préparât ion of €-Ohlorocapronit rile.— In a 2-1 . threenecked, round-bottom flask, fitted with a stirrer, a reflux condenser and a separatory funnel were placed 141.1 g. (1.0 mole) of 1 ,5-di chloropentane and 350 ml. of absolute ethanol. In the separatory funnel was placed 51.6 g. of 95/6 sodium cyanide (equivalent to 1.0 mole of IOO56 sodium cyanide) dissolved in 120 ml. of water.

The mixture was heated under

a reflux condenser with stirring and the cyanide solution slowly added.

This addition took three hours and the reflux-

ing was continued for an additional three hours. The solution was cooled and then diluted with 400 ml. of water and the chloronitrile was extracted with a 70ml. and-than 30-ml. portion of chloroform.

The chloroform

solution was washed with 200 ml. of calcium chloride solution (prepared by adding one volume of water to an equal volume of saturated solution of calcium chloride) and dried over fused calcium chloride. The dried solution was then distilled from a Glaisen flask.

The chloroform was removed by distillation at atmos­

pheric pressure until the temperature reached 120°G.

The

remainder was distilled at 3 mm. pressure and the following fractions were collected: (l) recovered 1 ,5-dichloropentane boiling from 5Q-70°0., 46.5 S«> (2) €.-chlorocapronitrile boiling from 70-95°0 ., 46.8 g. and (3 ) pimelonltrile boiling

24

from 95-l45°G., 20.5 g*

This was a yield of 53.2% and a

conversion of 6jm0% based on 1 ,5-dlchloropentane•

The

chlorooapronltrlle was redistilled at 85°0. at 5 mm. Anal. Pounds

Oalcd. for CgH-^NCl:

G, 54.8; H, 7.66.

G, 54.7; H, 8.0.

The yield of pimelonltrile was 16.8#. No increase In yield was obtained by adding the sodium cyanide solution slowly to the di chloropentane instead of adding it all at the beginning of the reaction. An attempt was made to prepare

chlorooapronltrlle

in the same manner as described above only using Oellosolve as the solvent at a temperature of 120°G. for three hours. These reaction conditions were too vigorous and. the reaction mixture turned black. Preparation of

The yield of nitrlle was only 15» 4#. € -Ohlorocanronitrile.— In a l-l. three­

necked, round-bottom flask fitted with a stirrer were placed 400 ml. of Oellosolve, 64.1 ml. (0.5 mole) of 1,5-dichloro­ pentane, and 25*5 8» of 96# sodium cyanide (equivalent to 0.5 mole of 100# sodium cyanide).

A thermometer was placed

in one of the necks so as to show the temperature of the reaction mixture. The flask was kept at 70 £ 5°0. with a Glas-col heating mantle and the reaction mixture was stirred twelve hours, not stirred for eleven hours, and stirred again for thirteen hours.

The total time of heating was thirty-six hours.

solution was cooled and filtered.

The

The residue of sodium

chloride and sodium cyanide was dried for fifteen hours in an oven at 110°G.

The dried residue was cooled and weighed

2Er

28.8? S« The filtrate was distilled at 25 mm. until the temper­ ature reached 60°G.

The portion remaining was filtered and

the residue of sodium chloride and sodium cyanide was dried for fifteen hours at liO°C. in an oven. 0.55 g.

This residue weighed

Total weight of the sodium chloride and sodium

cyanide was 29*42 g.

The filtrate was distilled and the

j£-chlorocapronltrile was collected between 80-95°0* at 4 mm.

This weighed 31*34 g.

The remaining portion distilled

at 95-l40°C. at 4 mm. and weighed 11.96 g. pimelonltrile.

This was chiefly

The yield of JE-chlorooapronltrlle was 57»

and the conversion was 82.5$ based on sodium cyanide. The yield and conversions were calculated as follows: 29*42 g. 1.00 g . impurities 28.42 g • of NaON and NaCl remaining. Let x s g. of NaCl y = g. of NaCN Then x + y = 28.42 x 58.5'

0.5 -

49

x » i.l93yy Then y a 4.30 g. of NaCN remaining or 24.5 - 4.30 s 20.2 g. of NaCN reacted. x 131*5

20.2 49

x « 54.2 g. theoretical yield. ■3 ^ *

x 100 - 57.856 yield.

26

24. b

Anal. Found:

x 100 s 82.5% conversion.

Oalcd. for O5H-LQNOI5

G, 54.8; H, 7 .66.

0, 54.7; H, 8.0.

Preparation of

€-Chlorocaproic Acid.— In a 500-ml.

three-necked, round-bot t om flask fitted with a water cooled reflux condenser and a dropping funnel waspplaced 241.5 S« of 70# sulfuric acid (1.726 mole of 100# acid).

In the

dropping funnel was placed 113.6 g. (O.863 mole) of 6 chlorocapronitrile.

The nitrlle was allowed to drop slowly

into the flask which was heated with a burner.

After the

reaction started, the burner was removed and the reaction continued until all of the nitrlle had been added.

At the

end of this time the mixture was re fluxed for an additional ten minutes and then for thirty minutes as 200 ml. of water was added through the dropping funnel. The solution was allowed to cool and then extracted with diethyl ether in a continuous liquid-liquid extractor for eight hours; then the ether solution was separated and dried over Drierlte. The dried solution was then distilled from a Glaisen flask.

The ether was removed by distillation at atmospheric

pressure.

The remainder was distilled at 6 mm. and the

portion boiling between 122-125°0. was collected.

This

weighed 111.0 g. and represents a yield of 85» 6#.

The pro­

duct was redistilled at 111°C. at 4 mm. Anal.

Oalcd. for GgH^OgOll;

0, 47.8; H, 7»36.

27

Found:

Q, 47.9; H» 7.40.

An attempt was made In another similar experiment to steam distill the mixture.

€ -chlorooaproic acid from the reaction

This method of isolation of the product did not

prove satisfactory. Préparation of 3-Ohloro- ^-bro mo oaproic Acid.— In a 200-ml. round-bottom flask were placed 79.4 g (0.527 mole) of € - chloro oaproic acid, 1.0 ml. of phosphorus tri­ chloride and 28.1 ml. (0.55 mole) of bromine which had been dried by washing once with 50 ml. of concentrated sulfuric acid.

The flask was fitted with a reflux condenser whose

top was connected with a trap and absorption bottle con­ taining water. The flask weesthen placed in an oil bath which was kept at 75-80°C. for five hours.

The temperature was then raised

to 100°0. and kept there for two additional hours.

The

reaction mixture was cooled and then 100 ml. of water was added to hydrolyze any acyl bromide present.

Sulfur dioxide

was passed through the mixture to remove the excess bromine. The two layers were separated and 100 ml. of ether added to the organic layer. and distilled.

This was dried over Drierlte, filtered,

The fraction boiling between 130-l40°0. at

3 mm. was collected and it weighed 101.1 g. which represented a 83.5$ yield.

The product was redistilled at 140-142°C. at

3 mm. Anal. Found:

Oalcd. for CgH^OgClBr:

0, 31*2; H, 4.23*

G, 31*4; H, 4.39*

28

After standing for two weeks the caprole acid crystallized.

£ -chloro- ^f-bromo-

After six recrystallizations from

heptane., the melting point was 35°0. Anal. Found:

Oaicd. for 06H1002CilBr$

°» 31.4; H, 4.39.

0, 31*3; H, 4.33.

Preparation of Lysine Using Aqueous Ammonia»— In a 125ml. Brlenmeyer flask was placed 53 ml. of aqueous ammonia (28.7#, sp. gr. 0.90) (0.80 mole).

To this was added 11.5

g. (0.05 mole) of -£ - chloro-^-bromocaproio acid, 24.0 g. (0.25 mole) of powdered ammonium carbonate and 0.21g. of cuprous chloride.

The mixture :was mixed well and transferred

to a nickel autoclave whose volume was approximately 75 ml. and whose diameter was 18 mm.

The molar ratio of acid,

ammonia, and carbon dioxide was 1,26,5. The autoclave was closed and heated for 24 hours at 80°0. without shaking.

At the end of this time the auto­

clave was cooled, opened, emptiedaand washed with two 10-ml. portions of water, the washings being added to the reaction mixture.

The solution was then filtered and the residue

being inorganic was discarded.

The filtrate was evaporated

under vacuum without outside heating nearly to dryness.

To

this was added 15 ml. of hydrochloric acid (37-38#, sp. gr. 1.19) (0.18 mole).

This was again evaporated nearly to

dryness under vacuum without heating. The residue was extracted with 40 ml. of alcohol and filtered while hot and the residue again extracted with 20 ml. of hot alcohol and filtered.

The filtrates were com-

29

blued and the residue discarded.

The filtrate was cooled

to 15°o. and 75 ml. of ether was slowly added with constant stirring.

The precipitate was filtered and weighed 2.2 g.

This was chiefly inorganic. The filtrate was evaporated to about 40 ml. and boiled with Norite and filtered while hot.

The filtrate was cooled

and 80 ml. of ether was added with constant stirring. precipitate was filtered and weighed 2.0 g.

The

This was re-

crystallized twice by dissolving in hot alcohol and precipitat­ ing with ether.

The final product weighed 0.7 g. and melted

at 187-189°C., the melting point recorded In the literature for lysine dihydrochloride. A similar run teasmade using the same amounts of materlalSB but at a temperature of 130°0. for 24 hours.

Only 0.5 g. of

lysine dihydro chloride was recovered. Attempted Preparation of Lysine Using Anhydrous Ammonia.— The nickel autoclave previously described was copied in a chloroform-carbon tetrachloride-dry ice-bath and then 11.5 g. (0.05 mole) of € -chloro-°S-bromocaprolc acid and 9*6 g. (6.1 mole) of ammonium carbonate were added.

To this 15 ml.

(0.7 mole) of liquid ammonia was added and the autoclave closed.

The autoclave was allowed to stand at room tempera­

ture for 12 hours and then heated at 50°0. for 24 hours.

At

the end of this time the autoclave was cooled and opened slightly to allow the ammonia to escape.

A viscous liquid

was scraped from the autoclave and weighed 19• 1 6 *

This

was placed in an ice-b&th and 25 ml. of hydrochloric acid

30

(37-38#, sp. gr* 1.19)} (0*30 mole) was added. An attempt was made to recover lysine dlliydrochloride In the same manner as In the experiments using aqueous am­ monia,

No lysine but a product weighing 1.4 g. and melting

at 235-24o°C. was recovered.

This may possibly be the

hydro chloride of 6- chloro -2-aminoc apro ic acid. Attempted Preparation of Lysine Using Potassium Phthalimlde.— In a mortar were placed 13*4 g. (0.05 mole) of the potassium salt of

€-chloro- °(-bromooaproic acid and

22.4 g. (0.12 mole) of potassium phthalimlde.

These were

ground together and well mixed and then transferred to a 100-ml., round-bottom flask fitted with a stirrer.

The

flask weaasplaced in an oil bath and heated to 190°C. at which temperature the solids melted into a viscous mass. was kept at 190 ± 10° for six hours.

The bath

To the solid remaining

was added 200 ml. of concentrated hydrochloric acid and the mixture was re fluxed for six hours.

The solution was then

cooledaand the phthalic acid filtered off. evaporated under reduced pressure.

The filtrate was

It was necessary to re­

move the inorganic salts which precipitated out during the evaporation.

The residue was taken up in 20 ml. of alcohol.

No lysine could be isolated from this solution. Preparation of 1.5-Dibromooentane.— In a 1-1. roundbottom flask was placed 341 ml. (3*0 moles) of 48# hydrobromic acid, 130.0 g. of concentrated sulfuric acid and 104.2 g. (1.0 mole) of 1,5-pentanediol.

A reflux condenser was

attached to the flask and the mixture was boiled under reflux

31

for six hours • ml. of water.

The mixture was cooled and diluted with 400 The bromide layer was separated, washed with

50 ml. of water and finally with a solution made by dissolv­ ing 20 g . of sodium carbonate in 200 ml. of water.

The pro­

duct was dried over 10 g . of calcium chloride for fifteen hours. 1 The dibromopentane was filtered from the calcium chlor­ ide and distilled.

The product was colledted between 104-

105°0. at 15 mm. and weighed 179*8 g.

This represents a

yield of 78.2#. Preparation of g -Bromocapronitrlle.— In a 500-ml. round-bottom flask was placed 115*0 g. (0.5 mole) of 1,5dlbromopentane, 200 ml. of absolute alcohol and 20 ml. of water.

A Soxhlet extractor with a condenser was attached

to the flask and 25*8 g. of 95# sodium cyanide (equivalent to 0.5 mole of 100# sodium cyanide) was placed in the extrac­ tion thimble.

The alcohol was refluxed through the sodium

cyanide for twelve hours. The flask was cooled and 20 g. of anhydrous potassium carbonate was added. was filtered. Pod column.

After standing for twelve hours, this

The filtrate was distilled using a three-foot After the alcohol was distilled off, the sodium

bromide was filtered from the residue and then the residue was distilledtthrough the same column. of 1,5-dibromopentanè was recovered.

From this 46.5 g* Then the jE-bromo­

capronitrlle was collected from 109-110°0. at 5 mm.

This

weighed 25.0 g. which represents a yield of 48.2# and a

32

conversion of 58.6#. The residue in the flask was hydrolyzed with concen­ trated hydrochloric acid to pimelic acid.

After drying the

plmellc acid weighed 5.1 g. which represents a yield of 10.9# of ilmelonitrile. Preparation of ^ -Bromocaprolc Acid.— In a 500-ml. three-necked# round-bottom flask fitted with a reflux con­ denser and a dropping funnel was placed 58.4 g. (0.417 mole) of 70# sulfuric acid.

In the dropping funnel was placed

24.5 g. (0.139 mole) of ^.-bromocapronitrlle and a small portion of the nit rile was added to the flask. was heated.

The flask

When the reaction commenced# the heat was re­

moved and the nit rile added at such a rate as to keep the reaction going.

After the addition of the nitrile was com­

pleted, the mixture wasrrefluxed for an additional 15 minutes. Then 50 ml. of water was added and the mixture re fluxed for thirty minutes longer. The mixture was cooled and extracted with ether in a continuous extractor for eight hours.

The ether layer was

separated and dried over Drlerite for twelve hours.

The

ether was distilled off and the residue distilled at 5 mm. The product was collected from 128-130°0. and weighed 16.2 g.

This represents a yield of 59*9#* Préparation of Ammonium Hydrogen Adinate.— In a 2-1.

round-bottom flask was placed a solution of 146.2 g. (1.0 mole) of adiplc acid in 1 1. of absolute ethanol.

The flask

was fitted with an efficient stirrer and then was placed in

33

an lee-bath.

in a graduate cylinder was placed 26*6 ml*

(1.0 mole) of anhydrous liquid ammonia (the density of am­ monia at -35°0• is approximately 0*64 g./ml* )•

The ammonia

was allowed to evaporate through a fritted disc 25 mm. in diameter and of medium porosity into the alcohol solution. This required approximately one hour.

The mixture was fil­

tered and the residue allowed to dry fifteen hours.

The

dried residue weighed 152.8 g. which represents a yield of

93*1%. The yield was reduced by reducing the amount of alcohol used as the solvent.

Although adiplc acid is very soluble

in alcohol, efficient stirring of the reaction mixture could not be maintained toward the end of the experiment unless an excess of alcohol were present. Preparation of Adioamic Acid.— In a 1-1. round-bottom flask was placed 152.8 g. (0.937 mole) of ammonium hydrogen adlpate.

The flask was then placed in an oil bath and heated

at 175 ± 5°C. for three hours. to cool.

The flask was then allowed

To the flask 200 ml. of water and 2.0 g. of Norite

were added.

The mixture was boiled for five minutes and

then filtered while hot to remove the Norite. was cooled in an ice-bath and filtered.

The filtrate

The filtrate was

concentrated to 50 ml. , cooled, and again filtered.

The

residues were combined and dried fifteen hours over sulfuric acid in a desiccator.

The adipamic acid weighed 123*5 8*

and melted from225-13O°0.

This represents a yield of 90.7^*

Thus the yield of adipamic acid based on adiplc acid

34

vas 85.036*: Attempted Dehvdrat i on of Adlpamio Aold with Thlonyl Ohlorlde.— In a 200-ml. , round-bot tom flask fitted with a reflux condenser was placed 50.0 g. (0.344 mole) of adipamic acid.

To this was added 150 ml. (2.08 moles) of purified

thionyl chloride (24).

The top of the reflux condenser was

then attached to a calcium chloride drying tube.

The mixture

was refluxed for three hours. Then the thionyl chloride was distilled off at atmos­ pheric pressure and the remainder distilled at 3 mm. pressure. The fraction boiling at 102-112°C. was collected.

This

weighed 34.7 g. and the residue remaining weighed 14.8 g. The distillate was redistilled and the fraction boiling between 103-104°0. at 3 mm. was collected. 27*9 g«

This weighed

This was distilled again and analysis showed 1.7336

nitrogen. Part of the distillate was added to water. giving off heat and a solid precipitated. was recrystallized from water and dried. 151°G.

It reacted

This precipitate It melted at 148-

There was no lowering with a mixed melting point with

adipic acid.

The distillate probably was adipyl chloride

and the nitrogen present was only an impurity. Attempted Dehydration of Adipamic Acid with Oalcium Carbide.— In a 200-ml. round-bottom flask were placed 41.7 g. (0.287 mole) of powdered adipamic acid and 22.4 g. (0.35 mole) of powdered calcium carbide.

These were mixed well

and then the flask was placed in an oil bath and heated at

150°C. «for four hours.

The material formed hard lumps,

probably due to the formation of the calcium salt of the acid. After cooling, 75 ml. of water was added to decompose the excess calcium carbide and then the mixture was filtered. The residue was acidified with an excess of hydrochloric acid.

No g-c y anovaleric acid could be recovered. Attempted Dehvdrat 1on of Adipamic Acid with Calcium

Carbide.— In a 500-ml. round-bottom flask was placed 43.5 g.

(d.30 mole) of adipamic acid and 150 ml. of toluene.

To

this was added 22.4 g. (0.35 mole) of powdered calcium car­ bide.

A reflux condenser was fitted to the flask and the

suspension was re fluxed for six hours. cooled and the toluene filtered off.

The solution was This was evaporated

and nothing remained in the toluene solution. To the residue was added 75 ml. of water and then 75 ml. of concentrated hydrochloric acid. heated to boiling and filtered.

The solution was

From the filtrate was re­

covered 35*1 g. of adipamic acid. Attempted Dehydration of Adipamic Acid with Phosphorus Pent oxide.— In a 200-ml. round-bottom flask was placed 43.5 g.

(0.30 mole) of adipamic acid.

To this was added 49.7

g.

(0.35 mole) of phosphorus pentoxide.

The mixture was

mixed and it began to heat and soon changed to a black tarry mass.

No attempt was made to isolate any product. Preparation of

Chi orovale r on!trile.——In a 500—ml.

round-bottom flask was placed 110.1 g. (0.867 mole) of 1,4—di-

36

ohlorobufcane, 250 ml. of absolute ethanol and 15 ml. of water. A Soxhlet extractor with condenser was attached to the flask and 46.4 g. of 95)6 sodium cyanide (equivalent to 44.1 g. of 100$ or 0.9 mole) was placed in the extraction thimble. The alcohol was re fluxed through the sodium cyanide thirtyfive hours. At the end of this time the weight of the sodium cyanide, after drying, which remained in the thimble was 9.9 g.

The

filtrate from the flask was distilled using a three-foot Pod column. was obtained.

Two hundred and five milliliters of alcohol This had the odor of an organic nitrile.

The residue in the flask was filtered and 1.2 g. of sodium chloride was obtained.

The filtrate was distilled as before

at a pressure of 12 mm. and 33*9 S« of 1 ,4-dichlorobutane boiling at 47°0. was recovered; then 32.2 g. of

5-chloro-

valeronitrile boiling at 95°0* at 9 mm. and 14.8 g. of adiponitrile boiling at 135% . at 4 mm. were obtained. There remained in the flask 3*0 g. of residue.

This re­

presents a yield of