PROCESS FOR PRODUCING ASPARTAME DERIVATIVE, CRYSTALS THEREOF, NOVEL PRODUCTION INTERMEDIATES THEREFOR AND PROCESS FOR PRODUCING THE INTERMEDIATE

摘要

3-(3-Hydroxy-4-methoxyphenyl)-3-methylbutyl aldehyde is produced by a reaction whereby the carboxyl group in 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyric acid, which can be obtained by reacting a 2-halogenoanisole with 3-methylcrotonic acid and converting the halogen atom in the thus produced 3-(3-halogeno-4-methoxyphenyl)-3-methylbutyric acid into a hydroxyl group, is converted into a formyl group. By a reductive alkylation reaction with aspartame, this aldehyde derivative can be easily and efficiently converted on an industrial scale into N-[N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-L- alpha -aspartyl]-L-phenylalanine 1-methyl ester which is useful as a sweetener having a high degree of sweetness. Thus, the aldehyde derivative is highly excellent as an intermediate for the production of the sweetener.