An Improved Method for ¹⁴C-Labeling of L-DOPS, a Norepinephrine Precursor Amino Acid

Abstract

(2S, 3R) -2-Amino-3- (3, 4-dihydroxyphenyl) -3-hydroxypropionic acid (L-DOPS) (1) was efficiently labeled with carbon-14 at the 3-position of the propionic acid moiety for use in mammalian metabolic studies. The synthesis was achieved according to the scheme illustrated in Fig. 2. Condensation of 3, 4-bis (benzyloxy) [carbonyl-¹⁴C] -benzaldehyde (7) with the optically active 5-oxazolidinone (8) gave the optically active alcohol (9) . Catalytic hydrogenation of 9 under acidic condition afforded 1. The overall yield of 1 was 74% from 7.