Benzo-fused nitrogen heterocycles by tandem processes involving nucleophilic aromatic substitution (SNAr) reactions

ORGN 498

Richard A. Bunce, rab@okstate.edu and Takahiro Nago. Department of Chemistry, Oklahoma State University, 107 Physical Sciences 1, Stillwater, OK 74078-3071
Benzo-fused nitrogen heterocycles have been prepared by tandem SN2-SNAr, SNAr-reductive amination and SNAr-Michael addition reactions. Analysis of molecular models suggests that the transition states for six-membered ring closures are optimum, and these are observed to give the best results. Five- and seven-membered ring formations are more difficult and give lower yields with more side reactions. Development of these cyclizations should permit access to products with novel substitution patterns, including several experimental drugs. The poster will present the synthesis of the cyclization substrates, the ring closure results, an analysis of the transition states and a mechanistic rationale for the formation of the products.