Condensation of 1,2,5-trimethyl-4-piperidone with p-diethynlbenzene

Abstract

A mixture of stereoisomeric diacetylenic piperidols was obtained by the reaction of 1,2,5-trimethyl-4-piperidone with p-diethynylbenzene in liquid ammonia in the presence of sodium amide. Each of the two pure alcohol and glycol geometrical isomers were isolated by chromatography with columns filled with aluminum oxide. Assumptions relative to the three-dimensional structure of the synthesized compounds are expressed on the basis of the principles of conformational analysis, the chromatographic data, and a study of the IR and NMR spectra. Saturated piperidols were obtained by catalytic hydrogenation on a Raney nickel catalyst.