RACEMIZATION OF OPTICALLY ACTIVE ALPHA-HYDROXY-BETA-AMINO ACID ESTER

• Main Authors: MIYAZAWA YOSHINOBU, KOSHIGOE TAICHI, SATO HISAO
• Format: Patent
• Language: English
• Published: 02.02.1993
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; APPARATUS THEREFOR; CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; GENERAL METHODS OF ORGANIC CHEMISTRY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; METALLURGY; ORGANIC CHEMISTRY; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE

PURPOSE:To racemize in high selectivity alpha-position and beta-position of unnecessary antipode of optically active alpha-hydroxy-beta-amino acid ester useful as a raw material for a medicine such as bestatin of an anticancer agent or renin inhibitor of an antihypertensive agent. CONSTITUTION:An optically active alpha-hydroxy-beta-amino acid ester being protected its amino group, e.g. optically active substance expressed by formula I (R is 1-8C hydrocarbon group; R and R are protecting groups; R is ester residue; * represents R or S) is oxidized to afford corresponding optically active alpha-oxo-beta-amino acid ester, e.g. an optically active substance expressed by formula II. Then the substance expressed by formula II is racemized and then alpha-oxo group thereof is reduced to return the oxo group to alpha-hydroxyl group. Thereby a racemic body of alpha-hydroxy-beta-amino acid ester, e.g. a compound expressed by formula III (relative configuration in 2 position and 3 position is threo configuration) is obtained in high selectivity. Furthermore, when the above-mentioned compound is subjected to optical resolution, necessary optically active substance is obtained and when unnecessary optical isomer obtained in this time is subjected to racemization and optical resolution according to the above- mentioned method, the unnecessary isomer can be converted into the necessary optically active substance.