Synthesis of regioisomeric pyrido[c]azocanones from azaindanone derivatives

Article abstract of DOI:10.1002/ejoc.201301736

A ring enlargement reaction with methylamine gave new pyrido[2,3-c]-, pyrido[3,4-c]- and pyrido[3,2-c]azocanone derivatives from cyclic β-oxo esters with a cyclopentapyridine skeleton and a 1,4-diketone moiety. The starting materials for this ring transformation were either prepared from halogenopyridine carboxylates by Heck reaction and subsequent hydrogenation, or (halogenomethyl)pyridine carboxylates were submitted to S_N reaction with diethyl malonate. Both routes were completed by Dieckmann condensation to build the cyclic β-oxo ester structure and alkylation with phenacylbromide to install the 1,4-diketone motif. Copyright