Criteria for the determination of the stereochemistry of steroidal indolizidines

Abstract

E/F-Indolizidine steroids, which represent a structural unit of Solanum alkaloids, have been synthesized and used to evaluate criteria (IR—Bohlmann bands,1a-c —hydrogenbond,2a-e NMR,3a-c mass spectra,4 kinetic studies of quaternization with methyl iodide,5a,b oxidation with mercuric acetate6) for the determination of the stereochemistry of these systems. It was found that the most reliable method is the measurement of the rate constants of quaternization of the bridgehead nitrogen with methyliodide.