An efficient route to 5-iodo-1-methylimidazole: synthesis of xestomanzamine A

Abstract

An efficient and practical route to C-5 functionalized N-methylated imidazoles is reported. 5-Iodo-1-methylimidazole was synthesized in four steps from imidazole, with complete regiospecificity, in 73% overall yield. The synthesis of xestomanzamine A, a marine natural product isolated in 1995 from an Okinawan sponge of Xestospongia sp., has been achieved using 5-iodo-1-methylimidazole in a modified Grignard reaction with a β-carboline ester moiety, in an overall yield of 59% based upon imidazole and 53% based upon tryptamine.Key words: xestomanzamine A, 5-iodo-1-methylimidazole, methyl β-carboline-1-carboxylate.