GB687486A - Improved method for the production of amino acids - Google Patents

Abstract

In a method for hydrolysing a hydantoin having the general formula <FORM:0687486/IV (b)/1> wherein R and R1 each independently represents hydrogen or a monovalent organic radical having a carbon atom thereof attached to the hydantoin nucleus, to form a salt of a corresponding a -amino-monocarboxylic acid, one molecular equivalent of the hydantoin is heated with an aqueous solution of at least two molecular equivalents of an alkali metal hydroxide, or an alkali metal carbonate, at superatmospheric pressure to a reaction temperature above 130 DEG C. for a time not greatly in excess of that required for completion of the hydrolysis reaction. The reaction may be carried out in a continuous manner by passing an aqueous mixture of the hydantoin and alkali through a heated reaction zone at a pressure sufficient to maintain the mixture largely, or entirely, in liquid form. Starting material hydantoins mentioned are hydantoin and hydantoins having in the 5-position methyl, ethyl, propyl, isopropyl, butyl, sec.-butyl, isobutyl, phenyl, benzyl, b -methylmercaptoethyl, (3-indolyl-methyl), dimethyl or diethyl substituents. In examples: (1) and (5) dl-tryptophane is prepared by heating 5-(3-indolylmethyl) hydantoin in a bomb with aqueous sodium hydroxide, and (3) with sodium carbonate or potassium hydroxide; (2) and (4) dl-methionine, leucine, isoleucine and alanine are produced by processes similar to that employed in example (1) from 5-(b -methylmercaptoethyl)-, 5-isobutyl-, 5-(sec.-butyl)- and 5-methyl hydantoin, respectively; (6) and (7) dl-tryptophane and dl-methionine are obtained by passing 5 - (3 - indolylmethyl) - and 5 - (b - methylmercaptoethyl)-hydantoins respectively with aqueous sodium hydroxide under pressure through a heated tubular autoclave. The free amino acid is obtained in each of the examples by acidifying the filtered hydrolysate with acetic acid.