Modern Friedel-Crafts chemistry. Part 32. Facile synthesis of some new fused heteropolycycles via direct intramolecular Friedel-Crafts cyclialkylations of suitable heteroarylalkanols

Abstract

This study provides expedient methods for the synthesis of some novel fused heteropolycycles. Thus, a variety of fused di-, tri- and tetracyclic nitrogen and nitrogen-sulfur heteropolycycles 8, 9, 11-15 were smoothly synthesized by Friedel-Crafts intramolecular alkylations of heteroarylalkanols 1-7 in the presence of both Brönsted (PPA and PTSA) and Lewis (AlCl 3/CH3NO2) acid catalysts. The precursor alkanols were readily prepared by reaction of the corresponding carboxylic acid esters with methylmagnesium iodide. The structures of the compounds are established using both spectral and analytical data. A plausible carbocation mechanism is proposed to account for the results. © ARKAT USA, Inc.