Patent ID: 7368600

Claim:
A method for producing L-methionine, D-methionine or a mixture of L— and D-methionine starting from homoserine, comprising converting L-homoserine, D-homoserine or mixtures of L- and D-homoserine of the formula I: to methionine by chemical transformation, without passing through any of the intermediates N-carbamoylhomoserine, 4—(2-bromoethyl)hydantoin and 4—(2-methyl-thioethyl)hydantoin; wherein the chemical transformation of L—and/or D-homoserine is carried out in a manner that comprises: a) using an acylating agent to produce N-acyl-L—and/or D-homoserine lactone of the formula VIII: where R is hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tertbutyl, phenyl, mono-, di- or trihaloalkyl, where halogen=F or Cl, CF 3 or CCl 3 , benzyloxycarbonyl or C 1 — to C 4 -alkyloxycarbonyl, b) reacting the N-acylhomoserine lactone obtained in step a) with MeSH in the presence of a basic or acid catalyst to give N-acylmethionine of formula VII: c) hydrolyzing the N-acylmethionine obtained in step b) at temperatures of >95° C. to give methionine.