Synthesis of pyrrolo[1,2-c]imidazol-5-one, pyrrolo[1,2-a]imidazol-5-one and pyrrolo[1,2-b]pyrazol-6-one (three isomeric azapyrrolizinones), by pyrolysis of Meldrum's acid derivatives
Abstract
Reaction of Meldrum's acid with the imidazole- and pyrazole-carbaldehydes (9)–(11) gave the condensation products (6), (7a), and (8) which were pyrolysed in the gas phase to give the title azaanalogues (2)–(4) of pyrrolizin-3-one (1), as air-sensitive yellow solids.