DE1070639B - Process for the preparation of Peptiderj - Google Patents

Description

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PATENT OFFICE ~ I

EXPLAINING EDITORIAL 1070 63S

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/ a N M E L D E TA G: SEPTEMBER 30, 1958

NOTICE IJ E R REGISTRATION AND EDITION OF THE EDITORIAL: DECEMBER 10, 1959

By publication by J. C. Sheehan and G. P. Hess (J. Amer. Ex. Soc., 77, pp. 1067 and 1068 [1955]) has dicyclohexylcarbodiimide as a mild condensing agent of great interest for peptide theses:

RCOOH + NH ₂ R '+ C ₆ H ₁₁ -N = C = NC ₆ H ₁₁ >RCONHR' + C ₆ H ₁₁ -NHCONH-C ₆ H ₁₁

This convenient method of peptide linkage is already one of the most common today (Th. Wieland and B. Heinke, Peptid-Synthesen III, Angew. Chem., 69, p. 368 [1957]). Even the synthesis of the / 3-lactam ring with the aid of dicyclohexylcarbodiimide to a fully synthetic penicillin in 10 ° / ₀ yield is recently succeeded (JC Sheehan and KR Hencry-Logan, J. Amer. Chem. Soc, 79, p 1262 [1957]).

The dicyclohexylurea formed by hydration during peptide synthesis is very sparingly soluble in the usual solvents and can easily be separated from them if the peptides formed remain in solution. However, in many cases, e.g. B. in the synthesis of peptides with large molecular weight, the peptide and the dicyclohexylurea have similar solubility properties, so that the peptide is very difficult to isolate. JC Sheehan and JJ Hlavka (J. org. Chemistry, 21, pp. 439 to 441 [1956]) therefore suggested using carbodiimides with a tertiary or quaternary amino group in the substituent in such cases. The ureas resulting from hydration are soluble in dilute acid or water and can therefore be easily separated from the peptides, which are sparingly soluble in water. One can use this basic carbodiimides peptides in a yield of 80 to 95 ° / ₀ of theory produce

The basic carbodiimides proposed by J. C. Sheehan and J. J. Hlavka, e.g. B.

Process for the production of peptides

Applicant:

Paint factories Bayer Aktiengesellschaft, Leverkusen-Bayerwerk

Dr. Hans-Bodo Konig, Wuppertal-Elberfeld,

and Dr. Fritz Moosmüller, Dormagen, have been named as the inventor

a primary or secondary carbon radical is replaced by a tertiary carbon radical; so is ζ. Β N-n-propyl-N'-tert-butyl-carbodiimide is significantly more stable As N-n-propyl-N'-isopropyl-carbodiimide on the other hand, it is also known that the reactivity of carbodiimides decreases with increasing stability (F. Moosmüller, University of Munich, dissertation 1953, p. 35). It was therefore to be assumed that N, N'-disubstituted carbodiimides with a tertiary or quaternary x \ minogroup in one substituent and a tert-alkyl group as the second substituent are storage-stable, but not because of insufficient reactivity for the formation of peptide bonds or are not very suitable.

Surprisingly, it has now been found that carbodiimides of the general formula

N-CH ₂ -CH ₂ -N = C = N

R ₁ -N = C = N-

R ₂ R ₃

N - ^ - Morpholino-ethylI-N'-cyclohexyl-carbodiimide

all contain one in addition to the remainder with a tertiary or quaternary amino group on atom (1) secondary carbon residue on atom (3), are therefore not very stable in storage and already partially polymerize, if you have larger quantities, d. H. 0.5 mol and more, distilled under an oil pump vacuum.

Through the work of E. Schmidt and coworkers (Chem. Ber., 74, pp. 1285 to 1296 [1941], and A., 560, pp. 222 to 231 [1948]) it was known that the storage stability of unstable carbodiimides can be greatly increased if one of the nitrogen atoms can be used very well as a reagent in the production of peptide bonds.

In this formula, R _w Rj7 -Bg ^{un <} i R4 are alkyl, cycloalkyl, aralkyl or Ai ^ lgfuppen, whereby at least one of these four radicals one or more tertiary and / or quaternary Aitäco groups must be substituted, so that R ₁ , R ₂ , R ₃ ntid "R ₄ can mean, for example:

2 - dimethylamino - ethyl -, 3 - dimethylamine - propyl -, 3 - diethylaminopropyl -, 3 - diethylamino - pentyl - (4) -, 4-dimethylamino-cyclohexyl-, 4-dimethylamino-phenyl-, β - (N'- Methyl - piperazino) - ethyl -, β - morpholino - ethyl

909 688/401

or the quaternary ammonium compounds derived therefrom.

O;

CH ₂ - CH ₂ - N = C = NC: - CH ₃

"CH,

CH ₃ CH ₃

^x ; N - CH ₂ - CH ₂ - CH ₂ - N = C = N - C [ CH ₃

N-CH ₂ -CH ₂ -CH ₂ -CH-N = C = NC ⁷ CH ₃

The following carbodiimides have proven themselves in the creation of peptide bonds:

C ₂ H ₅

CH _3x
CH ₃ "

CH, CH ₃
CH ₃ CH ₃

^ N-CH ₂ -CH ₂ -CH ₂ -N = C = N - C-CH ₂ -C-CH ₃

CH ₃

OJ

With the help of these carbodiimides, peptides can be represented in the known manner and from those formed Separate ureas.

example 1

3.1 g Sarkosinäthylester hydrochloride are suspended in 50 cc of methylene chloride, then at 0 ⁰ C 2 g of triethylamine was added, shaken for 3 minutes at ⁰ ° C, then suction filtered, washed with methylene chloride, the filtrate with the suspension of 4.2 g of carbobenzoxy -glycine combined in 400 ecm of methylene chloride and then 3.7 g of N - (3 - dimethylaminopropyl) - N '- tert. - butyl - carbodiimide was added and the mixture was then left to stand at room temperature for 24 hours, shaking occasionally. The clear solution was then washed with 1η hydrochloric acid, bicarbonate solution and water, dried over sodium sulfate and completely evaporated and dried in vacuo. Yield: 5.0 g (81 ° / ₀ of theory) of carbobenzoxy-glycyl-sarcosyl-ethyl ester a pale yellow oil whose composition was confirmed by paper chromatography.

Example 2

26.0 g of L-leucine methyl ester hydrochloride methylene chloride 14.1 g of triethylamine were dissolved in 550 cc suspended, was added, shaken for 3 minutes at 0 ⁰ C, filtered with suction, the filtrate is combined with the solution of 43.4 g of carbobenzoxy-glycyl-sarcosine, then 35.9 g of N- (3-diethylaminopentyl - (4) - N'-tert-butyl-carbodiimide were added, left to stand for 24 hours at room temperature and then worked up as described in Example 1. Yield: 56.9 g ( 98 ° / ₀ of theory) Carbobenzoxyglycyl-sarcosyl-L-leucine methyl ester;. a pale yellow, semi-solid oil the composition was secured by paper.

Example 3

2.4 g of L-leucine methyl ester hydrochloride were
50 ecm of methylene chloride suspended, mixed with 1.3 g of triethylamine, shaken for 3 minutes, filtered off with suction, the filtrate combined with the solution of 4.0 g of carbobenzoxy-glycylsarcosine in 100 ecm of methylene chloride, then 2.4 g of N-ß-dimethylaminopropy ^ - N'-tert-butyl-carbodiimide was added, left to stand for 24 hours at room temperature and, as described in Example 1, worked up. Yield: 3.8 g of carbobenzoxy-glycyl-sarcosyl-L-leucine methyl ester (71 ° / ₀ of theory), a solid oil.

60

Example 4

52 g of sarcosine ethyl ester hydrochloride were suspended in 800 ecm of methylene chloride, 33.6 g of triethylamine were added, ^{shaken at 0} ° C. for 3 minutes, then filtered off with suction, washed with methylene chloride, the filtrate with the suspension of 70.6 g of carbobenzoxy-glycine in 1680 ecm Combined methylene chloride, then 71.5 g of N - (/? - Morpholinoethyl) -N '- (tert-butyl) -carbodiimide added, the mixture left to stand at room temperature for 24 hours, then, as described in Example 1, worked up. Yield: 103 g (99 ° / ₀ of theory) of carbobenzoxy-glycylsarkosin acid ethyl ester as a solid oil.

Claims (1)

Claim: Process for the preparation of peptides by reacting nitrogen-protected amino acids or peptides with amino acids or peptides protected on the carboxyl group in the presence of Carbodiimides, characterized in that one carbodiimides of the general formula N = C = NC ^ R ₃ in which R ₁ , R ₂ , R ₃ and R _{4 represent} alkyl, cycloalkyl, aralkyl or aryl groups and at least one of these four radicals must be substituted by one or more tertiary and / or quaternary amino groups. © 909 688/401 12.