Synthesis of new pyrrolo[3,4-b]- and [3,4-c]pyridin(on)es and related 1,7-naphthyridinones and 2,7-naphthyridines via intramolecular Diels-Alder reactions of 2(1H)-pyrazinones

2(1H)-pyrazinones 7, 10 or 12 with in 6-position a 2-propynylaminomethyl or 3-butynylaminomethyl side chain undergo intramolecular Diels-Alder reactions providing cycloadducts which can he isolated or functionalised in some cases. By further thermolysis of these compounds either pyrrolo-[3,4-b]pyridinones 15/16 and/or pyrrolo[3,4-c]pyridines 17/18 or 1.7-naphthyridinones 25 and/or 2,7-naphthyridines 26 can be generated. Loss of either cyanide or isocyanate from the respective adducts is shown to be dependent on their substitution pattern. Copyright (C) 1996 Elsevier Science Ltd