摘要：

2-Substituted 1-tosyl-3,4,4-trimethylimidazolidines prepared by the addition of anions to 1-tosyl-3,4,4-trimethyl-2-imidazolinium iodide 1, react with tryptamine in the presence of acetic acid to give 1-substituted β-carboline derivatives. The salt 1 reacts with anions of 2-[2-(1,3-dithianyl)]benzoates 4a-c to give the corresponding imidazolidines 5a, 5b and 5c, respectively. These transfer the substituted fragment to tryptamine to give pentacyclic products corresponding to the yohimbane skeleton. The product from 5c yields, after reduction of both the amide and the dithiane function, the precursor of epi- and allo-yohimbanes.

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