Studies on the configurational stability of 3-(2-piperidyl)indoles

The cyclization of pure all-cis 3-(2-piperidyl)indole was carried out to examine epimerization reactions at the C-2 and C-4 positions of the piperidine ring. Specifically, the piperidine-4-carboxylic acids obtained from the saponification of the 3-(2-piperidyl)indoles were reesterified with excess diazomethane. The results revealed that epimerization occurs at the C-2 position of the piperidine during alkaline hydrolysis of the ester.