Selective Acylation of Amines by S-Acyl Se-Phenyl Selenosulfides

Abstract

Acylation of amino groups under mild conditions is important in the synthesis of alkaloids and amino glycosides. We found that S-acyl Se-phenyl selenosulfides (SSe-phenyl (selenothioperoxy)carboxylates) [1] which could be easily prepared from thiocarboxylic acid and N-(phenylseleno)phthalimide, served as the active acylating agent. Reaction of an amine with the selenosulfide [1] gave rather poor yield of the amide, but we examined various additives for this reaction and found the addition of mercury(II) acetate remarkably increased the yield. Thus, primary amines such as benzylamine, pyrrolidine as a secondary amine, and amines with a hydroxyl group such as 2-aminoethanol can be readily acylated at ambient temperature. Diamines such as putrescine and cadaverine, and spermidine were dibenzoylated. Maytenine was synthesized from spermidine and S-cinnamoyl Se-phenyl selenosulfide. Selenosulfides [1] have been found to be effective acylating agents which can react with various amines under mild conditions to give the corresponding amides.