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-methylbutylaldehyde is produced by subjecting 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyric acid to a reaction for converting a carboxyl group into a formyl group, whereby the carboxyl group in the butyric acid derivative is converted to a formyl group. Such 3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyric acid can be obtained by reacting 2-halogenoanisole with 3-methylcrotonic acid to produce 3-(3-halogeno-4-methoxyphenyl)-3-methylbutyric acid, and converting the halogen atom in the thus produced butyric acid derivative into a hydroxyl group. N-ÄN-Ä3-(3-hydroxy-4-methoxyphenyl)-3-methylbutylÜ-L- alpha -aspartylÜ-L-phenylalanine 1-methyl ester useful as a sweetener having a high degree of sweetness can be easily and efficiently derived on an industrial scale from the thus obtained aldehyde derivative in the reductive alkylation reaction with aspartame. Therefore, the aldehyde derivative is highly excellent as an intermediate for the production of the sweetener.