Patent ID: 8178722

Claim:
A method for producing theanine which avoids production of a metal salt and consists essentially of: (a) reacting in the presence of t-butylamine, a secondary amine or a tertiary amine: (1) a glutamic acid alkyl ester represented by general Formula (1): where R 1 represents an alkyl group, with (2) a ketone represented by general Formula (2): where R 2 represents a hydrogen atom, R 3 represents a lower alkanoyl group or a benzoyl group, and R 2 and R 3 may form a cycloalkanone ring in combination with the vicinal carbon atom; (b) reacting the step (a) reaction product represented by general Formula (3): where R 1 , R 2 and R 3 are the same as defined above, with ethylamine; and then (c) heating the step (b) reaction product in the presence of ethylamine or reacting the step (b) reaction product with a fatty acid; wherein the method does not comprise production of metal salts or purification steps to remove metal salts, and theanine is produced in yields of from 61 to 91%.