GB621477A - Improvements in or relating to amino acids - Google Patents

Abstract

Compounds of the general formula RR1CH.C(CN)(COOAlk)(NH.A), wherein R is a monovalent organic group not attacked by alkaline condensing agents, R1 is hydrogen or an alkyl group of not more than 6 carbon atoms, A is a carboxylic acyl group of not more than 4 carbon atoms and Alk is an alkyl group containing not more than 3 carbon atoms are obtained by condensing an ester of a lower acylaminocyanoacetic acid with a nontertiary organic halide containing the groups R and R1, other than a 4-(halomethyl)-imidazole where R1 is hydrogen, in the presence of an alkaline condensing agent. The compounds obtained may be converted to a -amino acids by hydrolysing and decarboxylating by treatment with dilute aqueous alkali or with a strong acid. The halogen compound RR1CHX may be either primary or secondary, e.g. ethyl iodide or isopropyl bromide, the group R may be heterocyclic, aryl, alkyl or unsaturated alkyl or alkenyl and may contain interrupting hetero atoms, e.g. sulphur in b -methyl mercaptoethyl. The alkaline condensing agents may be any of the alkali metal or alkaline earth metal alcoholates or alkoxides, alkali metals, alkali metal amides, and alkali metal triarylmethides. In examples, ethyl cyanoaceturate in a solution of sodium in dry ethanol is condensed with: (1) b -chloroethyl methyl sulphide and the ethyl 2 - acetamido - 2 - cyano - 4 - methylmercapto butyrate produced is refluxed with sodium hydroxide solution to obtain methionine; (2) with benzyl chloride, ethyl 2-acetamido-2-cyano-3-phenyl propionate is formed and on refluxing with hydrobromic acid or with an aqueous solution of sodium hydroxide, phenylalamine is obtained; (3) with methallyl chloride, the product is ethyl 2-acetamido-2-cyano-4-methyl-4-pentenoate and this is refluxed with an aqueous solution of sodium hydroxide to yield methallylglycine; (4) with allyl bromide, ethyl 2-acetamido-2-cyano-4-pentenoate being produced and then converted to allyl glycine by refluxing with sodium hydroxide solution as in (3); (5) with isopropyl bromide, the ethyl 2 - acetamido - 2 - cyano - 3 - methyl butyrate obtained being then refluxed with hydrobromic acid or with an aqueous solution of sodium hydroxide to yield valine; (6) with ethyl iodide, the ethyl-2-acetamido-2-cyano-butyrate produced is then refluxed with hydrobromic acid to yield a -aminobutyric acid. It is stated that the acylamino cyanoacetic ester may have the acyl group of formic, acetic, propionic or butyric acids and that the esters are those of methyl, ethyl, propyl or isopropyl alcohol. Specification 599,481 is referred to.