PREPARATION OF L-DOPA

• Main Author: KRUBINER A,US
• Format: Patent
• Language: English
• Published: 22.05.1973
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; BUILDING; BUILDING MATERIALS; CHEMISTRY; FIXED CONSTRUCTIONS; HETEROCYCLIC COMPOUNDS; HUMAN NECESSITIES; HYGIENE; MEDICAL OR VETERINARY SCIENCE; METALLURGY; ORGANIC CHEMISTRY; PREPARATIONS FOR MEDICAL, DENTAL, OR TOILET PURPOSES; STRUCTURAL ELEMENTS

1292975 Preparation of L-Dopa and novel intermediates F HOFFMANN-LA ROCHE & CO 16 Dec 1969 [27 Dec 1968] 61248/69 Heading C2C L - 3 - (3,4 - Dihydroxyphenyl) - alanine is prepared by treating a racemate of formula wherein R1 and R2 individually represent a hydroxy, lower alkoxy, acyloxy or phenyl- (lower alkoxy) group or R1 and R2 together represent a lower alkylenedioxy group and R3 represents an acyl group, with an optically active resolving agent of the general formula R4(R5)CHNH 2 , wherein R4 represents a phenyl or naphthyl group or a substituted derivative thereof, and R5 represents a lower alkyl group, to form the corresponding diastereomeric salts, separating these salts, converting the salts of the L-antipode into L-3-(3,4-dihydroxyphenyl) -alanine and, if desired, racemizing the D-antipode and leading the racemate back into the process, where lower denotes groups containing 1 to 7 C atoms. The L-isomers of the salts of Formula III: wherein R1 to R5 are as above and the free L- acids of formulµ wherein R'1 and R'2 are C 1-7 alkoxy or R'1 and R'2 together represent a methylenedioxy group, and R"1 and R''2 are each OH, C 1-7 alkoxy, phenyl (C 1-7 )-alkoxy or acyloxy, are claimed as novel compounds.