Synthesis process of theancine

Abstract

The invention discloses a method for synthesizing theanine, which involves reacting phthalic anhydride and excess L-glutamic acid at 120-180°C to generate phthalyl L-glutamic acid, which is then reacted with Acetic acid azeotropes for 3-20 minutes to form phthalyl L-glutamic anhydride, which is directly reacted with the ethylamine aqueous solution at room temperature to form phthalyl L-theanine. Add the hydrazine hydrate solution and leave it for two days. After removing the protecting group, L-theanine is obtained. This synthesis method has the advantages of low raw material prices, low production costs, fast reaction speed, high selectivity, and high yields, generally exceeding 50%.

Description

1. Technical field [0001] The invention relates to a synthesis method of theanine, belonging to the field of chemical synthesis. 2. Technical Background [0002] Theanine (L-theanine) is a unique component in tea, and is the free amino acid with the highest content in tea. It has a variety of medicinal and edible functions. Its structural formula is: CH 3 CH 2 NHCOCH 2 CH 2 CH(NH 2 )COOH. According to current literature reports, the chemical synthesis of theanine can be simply summarized into the following three synthetic routes: [0003] The first route: pyroglutamic acid (pyrrolidone acid) method, that is, the reaction of pyroglutamic acid and ethylamine to generate theanine. As early as 1942, Israeli Liechtenstein first used ethylamine and pyrrolidone acid to react in aqueous solution to obtain theanine in the laboratory. In 1951, the Japanese Hashizubin improved the synthesis method, that is, using L-pyrrolidone acid and pure ethylamine to react at low temperature...

AI Technical Summary

Problems solved by technology

Japanese A.Setsuko et al. (Japanese Patent 278848, 2001) protect the α-amino group of glutamic acid with the Z group (benzyloxyformyl), and mix it with the hydrochloride of ethylamine and triethylamine / sodium carbonate after forming an anhydride Then add it to dimethyl sulfoxide to synthesize N-substituted theanine, remove the protecting group Z group (benzyloxyformyl) by catalytic hydrogenation, and obtain theanine, but the price of the reagent used for the presence of benzyloxyformyl Expensive, the lack of organic solvents such as dimethyl sulfoxide and triethylamine for the reaction restricts its industrialization, poor selectivity, low yield, generally not higher than 30%

[0006] So far, the method of using phthaloyl group as the protective group of glutamic acid α-amino to synthesize L-theanine has not been reported in the literature. We have adopted this method to synthesize L-theanine at a lower production cost