The complete configuration of sedridine and of pelletierine

Abstract

Abstract (+)‐Sedridine from Sedum acre L. is shown to be (2S)‐1‐[(2′S)‐2′‐piperidyl]‐propan‐2‐ol. Oxidation of unnatural (‐)‐sedridine yielded D ‐pipecolic acid, from which follows the absolute configuration of the piperidine asymmetric centre. Oxidation of unnatural (+)‐pelletierine sulfate gave L ‐pipecolic acid. This also confirms a previous deduction of the absolute configuration of (‐)‐pelletierine from Punica granatum L.; this is R‐1‐(2‐piperidyl)propan‐2‐one. Racemic sedridine and allosedridine were condensed with p ‐substituted benzaldehydes to 1‐(4‐substituted‐phenyl)‐3‐methylhexahydro‐1 H ,3 H ‐pyrido‐[1,2‐c]oxazines. The relative configurations followed from conformational analysis and proton magnetic resonance spectra: sedridine is threoid and allosedridine is erythroid .