Compounds of the alpha-Prodine Type. V. Preparation of 1-Substituted Homologs and Analogs of 1-Benzoylethyl-4-Phenyl-4-Piperidinol and Their Esters. Reduction of Keto Esters to the Corresponding Hydroxy Esters.

摘要

The preparation and use of a number of Mannich bases and the corresponding methiodides for the synthesis of 1-substituted-4-phenyl-4-piperidinols and their ester hydrochlorides is described. Substituents in the 1-position included phenyl substituted benzoylethyl, 2-benzoylpropyl, 2-furoylethyl, 2-thenoylethyl, 2-(2-dibenzothenoyl), and 3-(2-thienyl)-2-propenyl groups. Monoesters were prepared by acylating the desired piperidinol with acyl halides of 2 to 4 carbon atoms; diesters were prepared by acylating 2 moles of the desired piperidinol with 1 mole of diacyl halide of up to 6 carbon atoms. An unusual diester was prepared by acylation of 1,4-bis(3-(4-pehnyl-4-hydroxy-1-piperidino)propionyl)benzene with 2 moles of a monoacyl halide. A successful, reliable method was developed for the catalytic reduction of keto ester hydrochlorides to the corresponding hydroxy ester hydrochlorides.