A method has been developed for the efficient and inexpensive synthesis of several benzo-fused heterocycles important in drug chemistry.  Earlier methods to prepare these ring systems utilized expensive Lewis acid catalysts, extended reaction times and elaborate purification schemes, which resulted in loss of product.  We have found that ammonium chloride is superior to these catalysts and generates the desired products in 85-95% yields without requiring subsequent chromatography.  The presentation will illustrate the preparation of benzimidazoles, benzoxazoles and benzothiazoles.  Ammonium chloride will be compared with other catalysts reported in the literature and a mechanism will be presented.

New approach to benzo-fused five-membered heterocycles

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.