Potassium Hydroxide → Pregabalin

Participants

Reaction Steps

150 g of (S)-5-methyl-3-nitromethyl-hexanoic acid ethyl ester (VIII, R1=ethyl; assay: 97.2%) were suspended in 300 mL of H2O. KOH (90.1.g, assay 86.1%, 2.05 eq.) was added. The initially turbid reaction mixture became clear which indicated that the reaction was nearly completed. After complete conversion (as determined by HPLC) the reaction mixture was transferred to a hydrogenation reactor. 90.0 g of an aqueous slurry of Raney Nickel were added. At a hydrogen pressure of 12 bar and a temperature of 45° C. the mixture was stirred until complete conversion was detected by HPLC giving 88.0 g of pregabalin in an aqueous solution.

Provenance & Evidence