Process for the preparation of amino acid methyl esters
The present invention describes a process for the synthesis of an amino acid methyl ester comprising the following steps: (a) refluxing a reaction mixture comprising a free amino acid, methanol and a strong acid; (b) concentrating the mixture; (c) adding methanol; (d) repeating steps a-c one or more times.
1. Process for the synthesis of an amino acid methyl ester comprising the following steps:
(a) refluxing a reaction mixture comprising a free amino acid, methanol and a strong acid at a temperature between 40 and 100° C.;
(b) while maintaining the temperature of the mixture of step (a) of between 40 and 100° C. concentrating the mixture obtained in step (a) to obtain a concentrated mixture thereof;
(c) adding methanol to the concentrated mixture obtained in step (b); and
(d) repeating steps (a)-(c) one or more times.
2. Process according to claim 1 wherein steps (a)-(c) are repeated at least 2 times.
3. Process according to claim 1 wherein the amino acid is an alpha-amino acid which is selected from the group consisting of D-phenylglycine, D-dihydro-phenylglycine and D-4-hydroxy-phenylglycine.
4. Process according to claim 1 wherein the strong acid is sulphuric acid.