1,2,3,4-Tetrahydro-1,5-naphthyridines and related heterocyclic scaffolds: Exploration of suitable chemistry for library development.

The chemistry of 1,2,3,4-tetrahydro-1,5-naphthyridines and 2,3,4,5-tetrahydro-1H-pyrido[3,2-b]azepines has been explored with the goal of discovering reactions at N1 suitable for library development. Epoxide openings, palladium-catalyzed N-arylations, DEPBT-promoted acylations, and urea formation through the reaction with isocyanates were all successful. The epoxide opening chemistry using homochiral epichlorohydrin, with epoxide reclosure and a second nucleophilic opening led to the preparation of a small 24-membered library.