Pregabalin → Pregabalin Impurity 25

Participants

Reaction Steps

In Synthesis 1989, 953 a synthesis of rac.-Pregabalin, starting from (E)-5-methyl-hex-2-enoic acid ethyl ester, which was converted with nitromethane into 5-methyl-3-nitromethyl-hexanoic acid ethyl ester, has been reported. Subsequent catalytic hydrogenation followed by saponification leads to rac.-Pregabalin. Recently an enzymatic hydrolysis of this racemic nitro ester was carried out (Tetrahedron Asymmetry 2008, 19, 945). With enzyme Novozyme 435 enantiomerically enriched (S)-5-methyl-3-nitromethyl-hexanoic acid could be obtained in a good selectivity if the conversion was stopped at 30%.

Provenance & Evidence