L-DOPA PROCESS

摘要

1351911 Derivatives and precursors for preparation of DOPA MONSANTO CO 7 March 1972 [8 March 1971] 10585/72 Heading C2C [Also in Division B1] 3-(31,41-Dihydroxyphenyl)-L-alanine is obtained by hydrolysis of the novel compound N- acetyl- - 3 - (41 - acetoxy - 31 - alkoxyphenyl)-L- alanine obtained by asymmetric hydrogenation ofα-acetamide-4-acetoxy-3-alkoxy-cinnamic acid and/or a salt thereof, e.g. using a co-ordination catalyst comprising iridium, ruthenium, osmium, palladium, platinum or rhodium and an optically active phosphine or arsine ligand. The D-isomer of N-acetyl-3(41-acetoxy-31-alkoxyphenyl)-4-alanine is obtained as a by-product. The novelα-acetamide-4-acetoxy-3-alkoxycinnamic acid is prepared by mild hydrolysis of 2- methyl - 4 - (41 - acetoxy - 31 - alkoxybenzyl) - 5- oxazolone obtained from 4-acetoxy-3-alkoxybenzaldehyde acetyl glycine and acetic anhydride.