Synthesis, resolution and absolute configuration of a tolperisone metabolite

1-(4'-Hydroxymethyl-phenyl)-2-methyl-3-(piperidine-1-yl)-propane-1-one M2, a metabolite of tolperisone, was synthesised in a solvent-free Mannich reac tion. The optical resolution was carried out by diastereoisomeric salt form ation and separation, for which three resolving agents ((2R,3R)-O,O'-dibenz oyl tartaric acid, (2R,3R)-O,O'-di-p-toluoyl tartaric acid and (R)-2-hydrox y-4-(2-methoxyphenyl)-5.5-dimethyl-1,3,2-dioxaphosphorinane-2-oxide (anicyp hos)) were found. The absolute configuration of M2 was determined by the si ngle-crystal X-ray diffraction method. (C) 2001 Elsevier Science Ltd. All r ights reserved.