Nature produces a number of piperidines having a long side chain. Among these compounds, the structure of carpaine being a dimeric 'lactone21 of carparnic acid (I) was completely elucidated as late as 1964. Since then, a number of related polyfunctional piperidine alkaloids such as cassinez, carnavalines, prosopine and prosopinine”'containing a Cl;-side chain as contrasted with the C8-side chain of carpaine have been isolated from ...