Design, synthesis, and preliminary pharmacological evaluation of 4-aminopiperidine derivatives as N-type calcium channel blockers active on pain and neuropathic pain
Several compounds with a 4-aminopiperidine scaffold decorated on both nitrogen atoms by alkyl or acyl moieties containing the structural motifs of verapamil and of flunarizine, as well as those that are more frequent in known N-type calcium channel antago
A scaleable route to the pure enantiomers of verapamil
A versatile route to single enantiomer verapamil from readily available raw materials is described. The key intermediate, 4-cyano-4-(3,4-dimethoxyphenyl)-5-methyl hexanoic acid (verapamilic acid), was resolved efficiently with α-methyl benzylamine. Stereochemical integrity at the quaternary carbon centre was preserved through subsequent steps to give either (R)-or (S)-verapamil in good overall yield. This sequence incorporated a selective borane-mediated reduction of a tertiary amide. Process scale-up to the pilot plant has been demonstrated successfully for the resolution step.
Bannister, Robin M.,Brookes, Michael H.,Evans, Graham R.,Katz, Ruth B.,Tyrrell, Nicholas D.
p. 467 - 472
(2013/08/07)
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