SOME LYSINE DERIVATIVES 
 
 BY 
 
 WILBUR ARTHUR LAZIER 
 
 THESIS 
 
 FOR THE 
 
 DEGREE OF BACHELOR OF SCIENCE 
 
 CHEMISTRY 
 
 COLLEGE OF LIBERAL ARTS AND SCIENCES 
 
 UNIVERSITY OF ILLINOIS 
 
 1922 
 

 
 
 
 
 
 ■ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
/ 3 22 
 L 45 
 
 UNIVERSITY OF ILLINOIS 
 
 May— 24^. 192 H— 
 
 THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION BY 
 
 -liibar- Yir-thu-r — Lazie r- 
 
 entitled Some- Lya ine— Dari-Ya.ti.Ye-S. 
 
 IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE 
 DEGREE OF Ba cli S IQ IL _ Qj— S_Q ie. EU2.0 lil _ CJi £J0 i& t Xy 
 
 
 
 Instructor in Charge 
 
 Approved : {jd _ 
 
 HEAD OF DEPARTMENT OF 
 
Digitized by the Internet Archive 
 in 2015 
 
 https://archive.org/details/somelysinederivaOOIazi 
 
ACEUO’kVLBDGMEITT 
 
 The writer wishes to express to Dr. G. 5. Marvel, under 
 whose direction this work was done, his sincere appreciation of 
 the many helpful suggestions tendered during the course of the 
 investigation. 
 

 
 
 
 
 
 
 
 •• 
 
 
 ' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TABLE 03? CONTENTS 
 
 Page 
 
 I . Ac knowl e dgement 
 
 II. Table of Contents 
 
 III. Introduction 2 
 
 IV. Historical and Theoretical 4 
 
 V. Experimental 
 
 Benzoyl piperidine 9 
 
 e-3enzoyl amino amyl chloride 12 
 
 6-Benz oyl amino amyl cyanide 14 
 
 6-Amino caproic acid 15 
 
 6-Benzoyl amino caproic acid 17 
 
 6-Benzoyl amino-a-brora caproic acid 18 
 
 6-Benzoyl lysine 20 
 
 dl-Lysine dihydrochloride 20 
 
 Calcium salt of 6-benzoyl amino-(X-hy- 
 
 droxy caproic acid 21 
 
 C-Amino- cx-hydroxy caproic acid 21 
 
 Copper salt of ex-hydroxy caproic acid 23 
 
 o (-Hydroxy caproic acid 23 
 
 Attempt to prepare e-hydroxy caproic acid 24 
 
 VI. Summary 25 
 
 VII. Bibliography 26 
 

- 2 - 
 
 INTRODUCTION 
 
 For a long time it has been known that lysine is neces- 
 sary in the diet of a normal white rat in order to produce growth* 
 Oshorne & Mendel x have shown that gliadin with its low content of 
 lysine as the sole source of protein of the diet does not permit 
 
 p 
 
 normal growth unless supplemented "by lysine. They^ have also shown 
 that chickens require a sufficient amount of lysine to make normal 
 
 growth. 
 
 little is known of the possibility of amino acid synthe- 
 sis in the animal organism. Perfusion experiments with the sur- 
 viving liver^ have shown that (X-hydroxy and cx-keto acids may he 
 converted to the corresponding optically active amino acids exist- 
 ing in the protein molecule. However, in the living organism, the 
 
 synthesis of a-amino acids by the reaction of NH_ and non-nitrog- 
 
 3 
 
 A 
 
 enous bodies has not been proved. Hart, Nelson, and Pitz^ were 
 unable to demonstrate a synthesis of lysine by the mammary gland 
 of the white rat, to supply an adequate milk for the young. 
 
 It seems probable that by conducting feeding experiments 
 with compounds containing hydroxyl groups corresponding to the 
 amino groups of lysine in all possible combinations, much light 
 might be shed upon the possibility of lysine synthesis in the an- 
 imal organism. Such experiments have never been conducted, due 
 to the necessary compounds being unavailable. 
 
 Therefore this investigation was carried out with the 
 idea of making available such necessary compounds which are listed 
 as follows: 
 

-3- 
 
 ot-£-diamino caproic acid (Lysine) 
 <x-amino caproic acid (Nor-leucine) 
 e-amino caproic acid (e-leucine) 
 e -amino -a-hy dr oxy caproic acid 
 c(-amino-e-hydroxy caproic acid 
 ot-e-dihydroxy caproic acid 
 ct-hydroxy caproic acid 
 
 NH -CH-CH-CH-CH -CH-COOH 
 2 2 2 2 ° 
 
 NH, 
 
 CH -CH -CH o -CH o -CH-C00H 
 
 3 2 2 2 Ah 
 
 NH -CH-CH-CH-CH -CH p -C00H 
 2 2 2 2 2 
 
 NH -CH -CH -CH -CH -CH-COOH 
 2 2 ° ° ° - - 
 
 2 2 
 
 OH 
 
 HO-CH -CH -CH -CH -CH-COOH 
 
 2 2 2 2 T\ra 
 
 2 
 
 HO-CH -CH 0 -CHo-CH 9 -CH-COOH 
 2 2 2 2 
 
 CH„-CH o -CH o -CH 9 -CH-C00H 
 
 2 2 c fog 
 
 HO-CH -CH -CH -CH -CH -COOH 
 2 2 <2 6 2 
 
 6-hydroxy caproic acid 
 
 Determinations of free amino nitrogen point toward the 
 fact that in lysine only one of the amino groups is combined in 
 peptide synthesis. The e-group is commonly thought to he the un- 
 
 5 
 
 combined group. Nor-leucine has been shorn by Lewis and Root to 
 be unable to supply the deficiency of a gliadin diet as does lysine 
 and shall be excluded from consideration here. 
 

 
 
 
 
 
 i. 
 
 
 
 
 
 
 
 
 
-4- 
 
 HISTORICAL AIID THEORETICAL 
 
 Lysine was discovered in 1899 by E. Drechsel 0 who found it 
 
 among the decomposition products of casein. Its presence in other 
 
 7 8 
 
 proteins was later shown hy his pupils Ernst Eischer , Siegfried , 
 
 and Hedin 5 . Lysine was also found "by Kutscher' 1 ' 0 in antipeptone 
 
 and by Kossel 1 " 1 " in the protamines. Its occurrence in germinating 
 
 12 
 
 seedlings was demonstrated by Schulze and in the vegetable pro- 
 
 .13 
 
 teins by Schulze and 7/inters te in' 
 
 Like arginine and histidine, 
 
 lysine is a very widely occurring constituent of the proteins. 
 
 14 
 
 Drechsel gave lysine the formula an<i regarded 
 
 15 
 
 it as a diamino caproic acid. In 1899 Ellinger proved that it 
 possessed this constitution by obtaining cadaverine from it by pu- 
 trefaction. This reaction also showed that the two amino groups 
 were in the ex and e position. 
 
 i T H 2 -CH 2 -CH 2 -CH 2 -CH 2 -9H-C00K *.C0g + Mg-CH^CHg-CH^CHg-CHg-Mg 
 
 - ITHg 
 
 T 6 
 
 Henderson's experiments also showed that lysine must be ct-e-di- 
 
 amino caproic acid. The constitution was finally definitely deter- 
 
 1 7 
 
 mined by Eischer and V/eigert by the following synthesis: ir-cyan- 
 opropyl malonic ester is treated with nitrous acid and loses one of 
 its carboxethyl groups and is converted into cx-oximido-^-cyano val- 
 erianic ester, which on reduction with sodium amalgam yields <x-e-di- 
 amino caproic acid. The reactions are: 
 
 n C-CEg-GHg-CHg-CH , 
 
 £00C o H c 
 
 / 
 
 -V NC-CH -CHg-CHg-C-COOCgHg 
 
 C00C 2 H 5 
 
 ITOH 
 
 nh 2 -ce 2 -ce 2 -ch 2 -ch 2 -ch-coch 
 

 
 
 
 * 
 
 
 * 
 
 
 
 
 
 ' t 
 
 
 
 
 
 
 
 
 
 
 
 
 
- 5 - 
 
 1 R 
 
 Sorensen also accomplished a synthesis in 1903 hy the following 
 series of reaction: 
 
 
 »COOC 0 H 5 
 
 fiQ* 
 
 ,C 00 C ? Hp: 
 
 = C c H„ N-CH & + K3r 
 
 C/-H/ UK + BrCH « ^ —v».n 
 
 6 'co' v cooc 2 h 5 6x co 'cooc 2 h 5 
 
 C0 V ^.COOGpHp 
 
 c Aa h-ch 
 
 6 x #0' K C00C o H 
 2 5 
 
 + G1-(CH 2 ) 3 CU 
 
 UaOCpHp- CO N .C00CpH R 
 K-CT-COOCpH? 
 
 6 ^ 0 / *^(CH JJs 
 
 c o 
 
 Na 
 
 .CO x ^COOCpHp- Con< 
 
 > 0 P H/, ii-g-cooc;h? 
 
 ° ( CH f 3 CH 1IH HC1 
 
 +alcohol 'Cd 
 
 * c 2 h e oh + co 2 + c 6 h 4 
 
 + HH„-CH„-CH„-CH 9 -CH.-CH-COOH 
 
 C* Cj Uj JT-r- 
 
 2 
 
 COOH 
 
 COOH 
 
 Neither of these syntheses were found to he very suitable 
 
 for the preparation of a good yield of lysine. A better synthesis 
 
 19 
 
 was described by J. von Braun • in 1909. Benzoyl piperidine is con- 
 verted by the action of phosphorus pentachloride into benzoyl amino 
 amyl chloride; the chlorine group is replaced by the CIT group which 
 is hydrolyzed to the COOH group. The resulting e-benzoyl amino 
 caproic acid is brominated with phosphorus and bromine. Treatment 
 with ammonia gives e-benzoyl amino -tf-amino caproic acid from which 
 lysine is obtained by hydrolysis. The reactions are: 
 
 C 6 H 5 
 
 "°-;d> 
 
 C 6 H 5 C °-f- CH E- CH 2 - CH 2 
 
 C H C0-UH-CH -CH -CH 0 
 6 5 1 2 2 2 
 
 C H CO-UH-CH -CH -CH 
 6 5 | 2 2 2 
 
 C H CO-HH-CH -CH -CH_ 
 6 5 t 2 2 2 
 
 C H CO-UH-CH -CH -CH 
 
 6 5 | 2 2 2 
 
 C 6 H 5 C°-1TH-CH2-CH 2 -CH2 
 
 NH 2 -CH 2 -CH 2 -CH 2 
 
 -ch 2 -ch 2 -ci 
 
 -CH -CH -I 
 
 2 2 
 
 -CH -CH -CN 
 2 2 
 
 -CH -CH -COOH 
 
 -CH -CHBr-COOH 
 2 
 
 -ch 2 -chm 2 -cooh 
 
 -CH -C HUH -COOH 
 
 cZ, cZ 
 

 
 
 
 
 
 • / 
 
 
 ' "/ K. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
- 6 - 
 
 The above synthesis was stated to he very satisfactory, hut the 
 
 actual yield of lysine from benzoyl piperidine was not stated. 
 
 Of the above syntheses, the latter gave most promise of 
 
 success and was adopted for the purpose of this investigation. As 
 
 no henzoyl piperidine was available, a method had to he worked out 
 
 21 
 
 for the preparation of this compound. In 1884 Ladenburg obtained 
 piperidine by the action of sodium on pyridine in an alcoholic so- 
 lution. The author states that the reaction goes only in a small 
 part, and no improvements have appeared in the literature since that 
 time. A method for the reduction of pyridine to piperidine by means 
 of sodium in alcoholic solution was perfected. The piperidine was 
 not isolated, but the crude product was converted into the benzoyl 
 derivative. By development of technique and by increasing the speed 
 of the reaction the yield was increased from about 70$ to 85-90$. 
 
 The benzoyl piperidine obtained by vacuum distillation 
 
 was treated with phosphorus pentachloride as with a few exceptions 
 
 20 1 9 
 
 described by Braun . Braun suggests that a better yield of 
 6-benzoyl amino amyl cyanide is obtained if iodine is substituted 
 for chlorine by refluxing the alcoholic solution with potassium io- 
 dide before the addition of the sodium cyanide. This was confirmed 
 by experiment. 
 
 6-Leucine was prepared as described by Braun 22 in 1907, 
 by the complete hydrolysis of 6-benzoyl amino amyl cyanide with hy- 
 drochloric acid. The amino acid was freed of the hydrochloric acid 
 by treatment with silver oxide and subsequent treatment with hydro- 
 gen sulfide to remove the excess silver from solution. This com- 
 
 23 
 
 pound has also been prepared by Gabriel and Maas by the complete 
 hydrolysis of phthalimido butyl malonic ester: 
 

 
 
 < 
 
 
 
 N 
 
 w - 
 
 . J , {, . 
 
 
 t 
 
 
 
 
 
 
 
 
 
-7- 
 
 COOH 
 
 + 2 G 2 H 5 OH 
 
 + C0 2 + im 2 -CE p -CH 2 -GH 2 -CH 2 -CH 2 -C00H 
 
 Upon heating, €-leucine condenses to form an inner amide 
 according to the reactions: 
 
 ITHg(CHg) 5 COOH 
 
 I + KgO 
 
 23 
 
 Gabriel and Maas" found this inner amide to he the product of the 
 
 vacuum distillation of e-leucine. By hydrolysis with hydrochloric 
 acid, the amide is converted to the hydrochloride of the amino acid. 
 
 zoyl chloride, and the resulting e-benzoyl amino caproic acid was 
 carefully dried and brominated with bromine and phosphorus. It was 
 found important to have all of the reacting substances very dry. 
 
 € -Benzoyl amino -cub rom caproic acid was treated with ammonium hy- 
 droxide and yielded the corresponding e-benzoyl amino -ae-amino capro- 
 ic acid which gave on hydrolysis lysine dihydrochloride. 
 
 treated with calcium carbonate yielding the calcium salt of 6-ben- 
 zoyl amino -oc-hy dr oxy caproic acid. Treatment with hydrochloric 
 acid liberated the free acid which gave on hydrolysis the hydro- 
 chloride of e-amino -<x-hydrozy caproic acid. From this the free 
 amino acid was prepared by the ordinary treatment with silver oxide. 
 
 Ct-Hydroxy caproic acid was obtained from a-brom caproic 
 
 £ -Leucine was benzoylated in alkaline solution with ben 
 
 6-Amino-oc-hydroxy caproic acid was prepared by the method 
 of Fischer and 3emplin^ 4 . 6-Benzoyl amino-a-brom caproic acid was 
 
 acid by boiling it with a solution of sodium carbonate. The acid 
 was isolated as the copper salt. Upon treating the copper salt 
 

- 8 - 
 
 with hydrogen sulfide, filtering, and evaporating under diminished 
 pressure, the free hydroxy caproic acid was obtained. 
 
 An attempt was made to obtain € -hydroxy caproic acid from 
 6-leucine. The latter was treated with nitrous acid at a low tem- 
 perature. The reaction mixture was extracted with ether and the 
 ether evaporated to dryness. A small amount of a white crystalline 
 compound with a fruity odor was obtained. The yield was very poor, 
 lack of time prevented further investigation of this and other 
 reactions • 
 
-9- 
 
 EXPERIMEUTA1 
 
 Benzoyl piperidine 
 
 A 5 liter flask is placed in an oil bath and is fitted 
 with a Y-tube carrying an efficient reflux condenser. 3 liters 
 of absolute alcohol and 130 grams of pyridine are placed in the 
 flask and 1 lb. of sodium is added through the Y-tube in 10 gram 
 portions during the course of 40 minutes. The sodium is added 
 rather slowly at first but may be added more rapidly as the boil- 
 ing point of the liquid increases, about one-half of the total 
 amount being added during the last 15 minutes. 
 
 Fifteen hundred cc. more of absolute alcohol is now add- 
 ed in 300 cc. portions at 5 minute intervals. Add a few small 
 pieces of clay plate, apply a flame to the oil bath, and reflux 
 until all of the sodium disappears. A large amount of melted 
 sodium will be present in the bottom of the flask which will rise 
 to the surface on refluxing and requires 2 or 3 hours for complete 
 solution. Replace the Y-tube with a stopper carrying a dropping 
 funnel and condenser arranged for downward distillation. As the 
 alcohol is distilled off, water is added until a total of 1800 cc. 
 has been added. (Caution: addition of water causes veiy rapid 
 
 distillation of alcohol.) 
 
 The distillation is carried on until a total of about 
 6 liters has been distilled over, at which time the distillate 
 will appear milky and the flask will contain only a concentrated 
 solution of NaOH which should be diluted at once and discarded. 
 
 The distillate is acidified with 300 cc. of cone. KC1 and the 
 alcohol distilled off on a steam cone leaving behind the piperi- 
 dine hydrochloride. This distillation is continued until a volume 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 !. 
 
 ' ) 
 
 * V- 
 
 
 
 
 
 
 
- 10 - 
 
 of about 600 cc. remains in the flask. Transfer the solution to a 
 2 liter flask using E00 cc. of v/ater to wash the solution complete- 
 ly into the second flask which is now fitted with a reflux condens- 
 er, dropping funnel, and mechanical stirrer running in a mercury 
 seal • 
 
 The mixture is vigorously stirred and a solution of 176 
 grams of NaOH in 300 cc. of water is added through the condenser. 
 235 grams of benzoyl chloride is run in through the dropping fun- 
 nel during the course of an hour. A pan of water near room temper- 
 ature is placed under the flask. The mixture is stirred 15 minutes 
 longer and allowed to stand for a few minutes, whereupon the ben- 
 soyl piperidine separates as a dark layer above the salt solution. 
 Pour the mixture carefully into a separatory funnel and draw off 
 the aqueous portion. The oily layer is removed to a 500 cc. 
 
 Claisen distilling flask and vacuum distilled. The first distil- 
 late may be pink in color but becomes a straw color upon a second 
 distillation. Boiling points: 
 
 At 17 mm. 191°-194° 
 
 At 130 mm. 240°-244° 
 
 For the purposes of this work a single distillation was found to 
 give a sufficiently pure product. A yield of E75-280 grams or 87- 
 89$ of the theory was obtained in several consecutive runs. 
 
 Notes. Unless the purity of the pyridine is known, it 
 should be distilled before use. For this work a fraction boiling 
 at 112°-117° was used. 
 
 A troublesome emulsion sometimes results after benzoyla- 
 tion. This may usually be broken up by the addition of more 
 strong NaOH solution. Any NaOH carried into the distilling flask 
 

 
 
 
 ... 
 
 
 
 
 
 
 
 
 
 
 
 
 
- 11 - 
 
 causes decomposition of the benzoyl piperidine and consequently a 
 considerably lower yield. For this reason it is well to wash the 
 product carefully in the separatory funnel with a little water after 
 the alkaline solution has been drawn off. In case an emulsion is 
 formed which cannot be broken up, it is possible to extract the 
 product with benzene. This is only necessary however in extreme 
 cases • 
 
 Benzoyl piperidine as obtained above is a straw colored 
 viscous liquid. Upon long standing or seeding with crystalline 
 benzoyl piperidine, the compound crystallizes in long colorless 
 needles which melt at 48° C. If the product is impure, it partial- 
 ly crystallizes to a semi solid consistancy. 
 
 It may be noted that a large excess of sodium is used. 
 
 For this reason it seemed possible that a larger portion of pyri- 
 dine might be reduced. Accordingly a run was made using 195 grams 
 of pyridine and the same quantity of sodium and alcohol. The bases 
 were neutralized with 300 cc . of EC1, later made alkaline with 250 
 grams of NaOH, and benzoylated with 360 grams of benzoyl chloride. 
 Yield: 345-365 grams, 71-75$. 
 
 Rapid reduction is necessary, the limiting factor being 
 the efficiency of the condenser. By shortening the time allowed 
 for the addition of the sodium from one hour to 40 minutes, the 
 yield was increased by 20$. The condenser used was 130 cm. in 
 length and had a diameter of 1.5 cm. This condenser gave consid- 
 erable trouble with clogging whereupon relief was obtained by re- 
 moving momentarily the stopper in the Y-tube. A condenser of 
 dimensions 2 X 180 cm. is recommended. The Y-tube had a diameter 
 of 3 cm. 
 

 . 
 
 
 
 
 
 
 
 
 f 
 
 . 
 
 . 
 
- 12 - 
 
 If the alcohol solution is allowed to cool before the 
 addition of the water, it solidifies and is only remelted with 
 great difficulty. If it is desired to suspend the process the 
 water should he first added and then the solution will not solidi- 
 fy* 
 
 Benzoyl piperidine is much given to superheating making 
 
 distillation difficult. 
 
 20 
 
 C-Benz oyl amino amyl chloride 
 
 Two hundred twenty grams of good quality benzoyl piperi- 
 dine is placed in a 1 liter round bottom flask together with 240 
 grams of C.P. phosphorus pentachloride . Attach the flask to a 
 reflux condenser with a tight fitting cork and warm gently. Have 
 in readiness a pan of ice water. The reaction is very vigorous 
 when once started and must be checked by application of the cold 
 water to the flask, in order to keep the foam from being carried' 
 up into the condenser. The mixture melts together in this manner 
 to a cherry red liquid. When the vigorous reaction has ceased, 
 reflux with a very low flame for 2-§- hours. 
 
 How cool the mixture slightly and with stirring pour it 
 slowly upon a kilogram of ice. A heavy oil separates in the bottom 
 of the beaker. Stir this up in the ice water in order to remove 
 as much of the free hydrochloric acid as possible and set aside 
 over night. Upon standing the tar changes to a more crystalline 
 mass. Decant the clear liquid, leaving the product in the beaker. 
 Upon breaking this up with a stirring rod it is found to be strong- 
 ly acid. Place the beaker containing the product in a pan of ice 
 water and stir into the latter, a solution of strong sodium hydrox- 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 . 
 
 
 
 
 
 
 
 
 
 . 
 
 
 
 
 
 
 
 
 
 
 
 
 * . ' v. 
 
 
 
 
 
 
 
-13- 
 
 ide until the liquid "becomes neutral. In this way the free acid 
 is completely removed from the product. Dilute to 1^- liters, heat 
 the neutral mixture just to boiling, and stir vigorously in order 
 to thoroughly wash the product. Allow the mixture to cool. Upon 
 standing the 6-benzoyl amino amyl chloride crystallizes as a solid 
 cake in the bottom of the beaker and as large flakes distributed 
 throughout the supernatent liquid. Yield about 170 grams or 65$ 
 of the theory. For the purposes of this investigation it was 
 found impractical to further purify the compound. It may be re- 
 crystallized from mixtures of water and acetone or of ethyl ether 
 and petroleum ether, in which cases the compound comes down in 
 pure white flakes which melt at 63° C. 6-Benzoyl amino amyl 
 chloride is easily soluble in all of the common organic solvents 
 except petroleum ether. J. von Braun 2 ^ succeeded in distilling the 
 compound in vacuum and gave its boiling point as 230-240° C. at 
 12 mm. 
 
 Notes: Hydrochloric acid is evolved during the reaction 
 
 and should be conducted from the top of the condenser through a 
 calcium chloride tube to a beaker of water. 
 
 It was found necessary to use C.P. phosphorus penta- 
 chloride as the commercial product reduced the yield appreciably. 
 According to Ruzicka the phosphorus pentachloride should be added 
 in four portions, the reaction mixture being heated to boiling and 
 cooled between successive portions, but it was found more conven- 
 ient and efficient to add it all at the beginning and to control 
 the reaction by means of ice water. 
 
 The time of boiling the reaction mixture was reduced 
 from !-§■ hours to £ hour with the result that the yield was greatly 
 
-14- 
 
 diminished. 2-|- hours seem to give the maxiumm yield. 
 
 In the development of the synthesis an attempt was made 
 to purify the crude 6-benzoyl amino amyl chloride by steam distil- 
 lation. By steam distillation without previous careful neutraliza- 
 tion almost the entire product was lost, due to hydrolysis. 7/hen 
 the crude product was carefully neutralized with sodium hydroxide 
 and sodium carbonate before steam distillation, hydrolysis did not 
 take place and about 5 cc. of a light oil was obtained, probably 
 pentamethylene chloride. This method was abandoned as having few 
 advantages . 
 
 6-Benzoyl amino amyl cyanide^ 9 
 
 Without further purification, the chlorine compound ob- 
 tained in the above preparation is dissolved in 800 cc. of alcohol 
 and refluxed on the steam bath with 160 grams of potassium iodide 
 for about 10 hours. The mixture is cooled, whereupon the insoluble 
 salts separate out and are filtered off. A solution of 140 grams 
 of sodium cyanide in 300 cc. of water is now added and the mixture 
 refluxed once more, this time for about 20 hours. At the end of 
 this time the condenser is arranged for downward distillation and 
 the alcohol is distilled off until only about 400 cc. remains. 
 
 This residue is poured into a liter of cold water and the mixture 
 thoroughly stirred up to wash the cyanide. Upon standing, the 
 6-benzoyl amino amyl cyanide solidifies, partly as a solid crystal- 
 line cake and partly as almost white crystals from the water-alco- 
 hol liquid. Yield of crude product is about equal to the weight of 
 chloride compound used. The product is impure and the actual yield 
 of cyanide is difficult to determine. This product is directly 
 

-In- 
 applicable for hydrolysis to either f'-benzoyl amino caproic acid or 
 to €-amino caproic acid. For purification the cyanide may he re- 
 crystallized from 30 jo alcohol. Melting point: 95° C. 
 
 Notes: J. von Braun 1 ^ calls attention to the fact that 
 
 hy going from the chlorine compound to the cyanide through the 
 corresponding iodine compound, the yield is much better than in 
 the case of direct substitution of cyanide for chlorine. This was 
 confirmed by experiment. 
 
 pp 
 
 6-Amino caproic acid*'"'' 
 
 One hundred grams of the crude e -benzoyl amino amyl cya- 
 nide is placed in a 1 liter flask and refluxed with 500 cc . of 1 to 
 1 hydrochloric acid for 9 hours. The mixture is then cooled and 
 the benzoic acid and unhydrolyzed residue (about E5 grams) is fil- 
 tered off. The filtrate is evaporated to dryness on the water 
 bath. The residue is brown in color and consists of the hydro- 
 chloride of 6-amino caproic acid and some inorganic salts as im- 
 purities. The residue is taken up in 300 cc. of absolute alcohol 
 and filtered from the inorganic salts. The alcoholic filtrate is 
 evaporated to a paste. The dish containing the hydrochloride is 
 placed in an ice bath and a mixture of 50 grams of silver oxide 
 and 50 cc. of water is stirred into it. After about 10 minutes 
 the mixture is diluted with water to 250 cc. and filtered. Hydro- 
 gen sulfide is passed into the cold solution until a portion of 
 the filtrate no longer gives a test for silver with hydrochloric 
 acid. This will require from 3 to 4 hours at room temperature. 
 
 The silver sulfide precipitate is filtered off and the filtrate 
 vacuum distilled at a temperature of 45°. The distillation is con- 
 
-16- 
 
 time & until the amino acid crystallizes as a soft crystalline 
 mass. It is now washed out of the distilling flask and triturated 
 with absolute alcohol, decanted through a filter, fresh portions 
 of absolute alcohol added, and the process repeated until the 
 6-amino caproic acid becomes pure white and very finely divided. 
 Finally it is washed into the filter and dried. Yield: 12 grams 
 or 20$ from the crude cyanide. 
 
 € -Amino caproic acid is a white, finely crystalline com- 
 pound. It dissolves easily in water but is insoluble in ether and 
 absolute alcohol. At 203° C. it melts to a colorless liquid. 
 
 Notes: The unhydrolyzed residue may be collected and 
 
 again refluxed with hydrochloric acid. 
 
 The alcoholic solution of the hydrochloride of the amino 
 acid is deeply colored. Bone-black was used in an attempt to de- 
 colorize this solution but seemed to have little effect. 
 
 When heated € -leucine readily forms an inner amide. 
 
 When the solution of the free amino acid was evaporated in the or- 
 dinary way on the steam cone, the yield of the amino acid was 
 greatly diminished, due to the formation of this amide. Even in 
 the case of vacuum distillation, the yield of the inner amide was 
 slightly greater than that of the free amino acid. This amide is 
 very soluble in alcohol and is removed by extraction of the amino 
 acid with absolute alcohol. Upon concentration of the alcoholic 
 extract and subsequent hydrolysis with hydrochloric acid, the in- 
 ner amide was converted quantitatively into the hydrochloride of 
 the amino acid. 
 
 Litharge was used in an attempt to free the amino acid 
 from the hydrochloride, but complete removal of the chlorine could 
 

 
 
-17- 
 
 not be obtained by this method. 
 
 e -Benzoyl amino caproic acid 4 ^ 
 
 One hundred grams of the crude e-benzoyl amino amyl cya- 
 nide is completely hydrolyzed with hydrochloric acid as in the 
 preparation of e-amino caproic acid. The product is dissolved in 
 alcohol as before and filtered from the insoluble inorganic salts. 
 The hydrochloride obtained by the evaporation of the alcohol is 
 taken up in a solution of 400 cc. of water and 100 grams of sodium 
 hydroxide. The mixture is cooled and placed in a flask equipped 
 with a mechanical stirrer. 50 grams of benzoyl chloride is run in 
 with stirring during the course of 30 minutes. Stirring is contin- 
 ued 15 minutes longer. Filter with suction to remove any benzamide 
 which has been formed. The solution is acidified, whereupon the 
 6-benzoyl amino caproic acid separates as a heavy oil. Upon stand- 
 ing over night this changes to a brown, oily, crystalline mass. 
 
 The mother liquor is decanted and the acid is dried bet ween clay 
 plates in a vacuum dessicator. The product is now applicable for 
 bromination. Yield from 100 grams of cyanide 45 grams, 41$ of the 
 theory. 6-Benzoyl amino caproic acid is easily soluble in ether 
 or alcohol and insoluble in petroleum ether. It may be recrystal- 
 lized from ether and alcohol. The compound crystallizes in long 
 needles which mat together in a sticky mass. Melting point: 79° C. 
 
 Notes: By boiling the cyanide with 50 grams of sodium 
 
 hydroxide, £00 cc. of water, and 500 cc. of alcohol for 3 hours 
 the cyanide may be saponified without effect upon the benzoyl radi- 
 cal. The product is very difficult to separate from the reaction 
 mixture and contains a great many impurities from the crude cyanide 
 
- 18 - 
 
 which cannot be removed. Both methods were thoroughly investigat- 
 ed and it was found more practicable to completely hydrolyze and 
 benzoylate bach as described above. 
 
 In some cases a crystalline product was not formed even 
 after standing several days. The cause of this failure was not 
 determined. An attempt was made to benzoylate the 6-amino caproic 
 acid without first removing the inorganic salts. In this case a 
 large amount of benzamide and benzoic acid was formed and the 
 yield was considerably reduced. 
 
 6-Benzoyl amino-oubrom caproic acid 
 
 Forty grams of C -benzoyl amino caproic acid is very 
 thoroughly dried over sulfuric acid in a vacuum dessicator. The 
 dry acid is mixed in a mortar with 5 grams of red phosphorus which 
 has also been previously dried. The red viscous mass is scraped 
 into a 500 cc . flash equipped with a rubber stopper bearing a 
 calcium chloride tube and a small dropping funnel. Forty cc. of 
 bromine, which has been dried under sulfuric acid, is placed in 
 the funnel and allowed to drop slowly upon the reaction mixture. 
 The first drops of bromine react violently with the appearance of 
 fire. After the first few cc. have been added, the remainder of 
 the bromine is allowed to flow at the rate of about 60 drops per 
 minute. The reaction mixture is hept in a plastic state by cool- 
 ing the flash in a dish of cold water. 
 
 After all of the bromine has been added, the calcium 
 chloride tube and dropping funnel are replaced by an air condenser 
 closed at the upper end by a calcium chloride tube. The flash is 
 now heated on the steam bath until the evolution of hydrobromic 
 
-19- 
 
 acid is complete. This will require about 12 hours. The mixture 
 is poured slowly and with stirring into 500 cc. of ice water. As 
 the acid chloride is decomposed, the free acid separates as a 
 brown solid mass. Sulfur dioxide is now passed into the brown 
 solution just until no more bromine color is apparent. The mass 
 of acid in the bottom of the beaker must be thoroughly broken up 
 by stirring in order to remove the excess bromine. The crumbly, 
 brown mass is allowed to dry, triturated with 50 cc. of ethyl 
 ether, and filtered with aiction. It may be washed with a few 
 cc. of ether to remove any unchanged acid. Yield: 20 grams, 37$ 
 
 of the theory. 6-Benzoyl amino -cx-brom caproic acid is insoluble 
 in water, easily soluble in hot alcohol, and only slightly solu- 
 ble in ether. It may be purified by recrystallization from dilute 
 alcohol. Melting point: 166° 0. The brom acid obtained by this 
 
 method may be red in color when dry due to incomplete removal of 
 the bromine. 
 
 Ilotes: The reactive substances must be very thoroughly 
 
 dried in order to prevent the premature decomposition of the acid 
 chloride . 
 
 Caution must be used in pouring the reaction mixture 
 into water as the decomposition of the acid chloride is accompan- 
 ied by the evolution of heat, and the reaction is very vigorous 
 if the water becomes hot. It should be kept cool and allowed to 
 progress slowly. 
 
 J. von Braun recommends that the crude acid be dissolved 
 in alcohol after decolorising with sulfur dioxide. After fil- 
 tration of the alcoholic solution the acid is precipitated by 
 addition of water. This was found to be unnecessary. 
 

 . 0 
 
 
 
 
 
 
 l 
 
 
 
 
 
 .. . . - V ' 
 
 
 N 
 
 
 
 
 ‘ 'C 
 
 
 :i 
 
 
 
 
 ! 
 
- 20 - 
 
 € -Benzoyl lysine 
 
 Thirty grams of 6-benzoyl amino-a-brom caproic acid is 
 placed in a strong, well stoppered bottle with 300 cc. of 
 ammonium hydroxide. The bottle is put in a warm place and held 
 at 30°-40° for two days. The contents are filtered, any residue 
 being washed with two portions each of 200 cc. of hot water. If 
 solution of the product does not appear to be complete, more hot 
 water may be used. The combined filtrates are evaporated to dry- 
 ness upon the steam bath whereupon the product separates in large 
 white flakes. The residue is triturated with 75 cc. of absolute 
 alcohol, filtered, and washed into the filter with small portions 
 of absolute alcohol. Yield about 12 grams or 50% of the theory. 
 e-Benzoyl lysine is insoluble in alcohol and ether and is only 
 slightly soluble in v/ater. It melts at 265° C. 
 
 dl -lysine dihydrochloride 
 
 Twelve grams of 6-benzoyl lysine and 50 cc. of cone, 
 hydrochloric acid is placed in a thick walled glass tube and the 
 tube is sealed off. The reaction mixture is heated at 115°-125° 
 in an oil bath for 5 hours. At the end of this time the tube is 
 cooled and opened and the acid diluted with 75 cc . of v/ater. 
 
 The separated benzoic acid is filtered off and the filtrate ex- 
 tracted twice with 40 cc . of ether. 
 
 The acid solution is then boiled with 2 grams of bone- 
 black ( "Norite") for 5 minutes and filtered. The filtrate is 
 evaporated on the steam hath to a light yellow syrup. This is 
 taken up in 100 cc. of absolute alcohol and filtered. Upon cool- 
 ing and adding an equal volume of dry ether, the hydrochloride 
 
-El- 
 
 separates as a sticky mass in the bottom of the beaker. After the 
 liquid has become clear, decant the alcohol-ether mixture and dry 
 the hydrochloride in the beaker in a dessicator. After drying for 
 2 or 3 days, the lysine hydrochloride may be scraped from the 
 beaker. The yield from 12 grams of benzoyl lysine is 5 grams or 
 about 47 % of the theoretical amount, lysine hydrochloride readily 
 absorbs moisture from the air and must be kept in a tightly stop- 
 pered bottle. It is very soluble in water and alcohol but insolu- 
 ble in ether. It melts v/ith decomposition at 192°-193° C. 
 
 Calcium salt of 6-benzoyl amino -oc-hydroxy caproic acid 
 
 Thirty grams of 6-benzoyl amino-d-brorn caproic acid is 
 dissolved in 375 cc. of hot Q0% alcohol, and 10 grams of precipi- 
 tated calcium carbonate is stirred into the solution whereupon 
 strong evolution of carbon dioxide takes place. The turbid sus- 
 pension thus formed is poured slowly into 3-g- liters of boiling 
 water, and 15 grams of calcium carbonate is again added. The mix- 
 ture is boiled 15 minutes longer, then filtered, and the liquid 
 evaporated under diminished pressure to about 250 cc. The calcium 
 salt of €-benzoyl amino - ct-hy dr oxy caproic acid separates as a fine, 
 crystalline, powder which is filtered from the yellow mother 
 liquor. The yield is 20 grams or about 72% of the theory. The 
 product is of a light yellow color. 
 
 P4- 
 
 e- Amino -Ct-hy dr oxy caproic acid 
 Thirty grams of the calcium salt of 6-benzoyl amino- 
 OC-hydroxy caproic acid as prepared above is treated with 25 cc. of 
 5-normal hydrochloric acid which is then diluted with water to a 
 volume of 60 cc. The salt slowly goes into solution and a heavy. 
 
- 22 - 
 
 reddish brown oil separates in the "bottom of the flask. The acid 
 solution is cooled to C° C. and decanted. 
 
 The oil remaining in the flask is dissolved in 200 cc. of 
 5-normal hydrochloric acid and refluxed for 5 hours. Upon cooling, 
 "benzoic acid crystallises out and is separated "by filtration. The 
 acid solution is then extracted 3 times with 50 cc. of ethyl ether 
 to remove the last traces of "benzoic acid from solution, and is then 
 evaporated under diminished pressure to a thick syrup. The syrupy 
 residue is dissolved in 150 cc. of water and treated with 25 grams 
 of silver oxide. After about 10 minutes the liquid is filtered. A 
 portion of the filtrate should give no turbidity with a drop of 
 silver nitrate solution. The filtrate is now saturated with hydro- 
 gen sulfide to precipitate any dissolved silver and the the solu- 
 tion is again filtered. The final filtrate is evaporated almost to 
 dryness under diminished pressure. The €-amino-o£-hydroxy caproic 
 acid separates as microscopic, white crystalls, which are triturated 
 with absolute alcohol, filtered, and washed to whiteness with alco- 
 hol. Yield: 8 grams or about 50%. The acid melts with decomposi- 
 
 tion and a brown coloration at 220 u -225°. 
 
 pA 
 
 Notes: Uischer and Zemplin isolated the 6-benzoyl 
 
 amino -tt-hydroxy caproic acid. Upon standing in a cold place the 
 brown oil described above changes to a crystalline solid which may 
 be recrystallized from boiling water. It dissolves easily in alco- 
 hol and acetone and with difficulty in ether. The melting' point 
 was given as 107° 0. 
 
 The above authors used hydrochloric acid to remove the 
 excess silver from solution but it was found more satisfactory to 
 use hydrogen sulfide instead. 
 
-23- 
 
 The final solution for evaporation is of a straw yellow 
 color. Bone-black was used in an attempt to remove this color 
 but seemed to have little effect. During evaporation the color be- 
 comes intensified. By washing the product with absolute alcohol, 
 practically all of this coloring matter is removed. 
 
 Copper salt of <X-hydroxy caproic acid 
 
 Seventy grams of a-brom caproic acid was dissolved in a 
 solution of 70 grams of sodium carbonate in a liter of water. The 
 solution was boiled thirty minutes, cooled, and filtered to remove 
 a small amount of a waxy residue from the (X-brom caproic acid. The 
 filtrate was again heated to boiling, and 35 grams of copper acetate 
 was added and stirred until completely dissolved. The copper salt 
 of cx-hyaroxy caproic acid precipitates as a light colored scum. 
 
 The solution is allowed to cool and crystallize out and the copper 
 salt is filtered off and washed on the filter with cold water. It 
 is of a light blue-green color. Yield: 40 grams or 60$ of the 
 
 theory. 
 
 (X-Eydroxy caproic acid 
 
 Twenty grams of the copper salt of d-hydroxy caproic acid 
 was placed in a 1 liter flask and shaken with 800 cc. of boiling 
 water until all of the salt was in suspension or in solution. The 
 liquid was now kept hot and saturated with hydrogen sulfide for 
 5 hours. A colloidal solution appeared to have been formed. This 
 was broken up by allowing the liquid to stand several days after 
 which it was filtered. The filtrate and washings were evaporated 
 under diminished pressure to a syrup. Upon cooling, this syrup 
 

-25- 
 
 SUMMARY 
 
 1. An improved method for the preparation of benzoyl 
 piperidine has been developed. 
 
 2. Benzoyl piperidine has been converted into 6-amino 
 caproic acid, e-amino -cx-hydroxy caproic acid, and into dl -lysine 
 dihydrochloride by reactions previously studied by J. von Braun 
 and by E. Fischer and Zemplin. 
 
 3. <x-Hyaroxy caproic acid has been prepared from the cor- 
 responding brom compound. 
 
 4. 6-Hydroxy caproic acid could not be obtained in reason 
 able yields from e-amino caproic acid by the action of nitrous 
 
 acid. 
 
 5. Sufficient quantities of €-amino caproic acid, cX-hy- 
 droxy caproic acid, dl-lysine dihydrochloride, and e-amino-Qf-hy- 
 droxy caproic acid have been prepared for the study of their be- 
 havior in metabolism experiments. 
 
-26- 
 
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