3-Hydroxypyrroles and 1H-Pyrrol-3(2H)-ones. Part 2. Scope and Limitations of the Synthesis of Pyrrol-3-ones by Pyrolysis of Aminomethylene Meldrum's Acid Derivatives.

Article abstract of DOI:10.1039/P19880000863

Flash vacuum pyrolysis of N,N-disubstituted aminomethylene Meldrum's acid derivatives provides a route to 4,5-unsubstituted 1H-pyrrol-3(2H)-ones by a hydrogen-transfer-cyclisation sequence.Alkyl and aryl 1-substituted, 1,2-disubstituted, and 1,2,2-trisubstituted pyrrolones can be obtained.In competitive cases, there is little selectivity between hydrogen transfer from primary, secondary, or tertiary sites, although benzyl hydrogen atoms proved particularly reactive, giving a general synthesis of 2-phenyl-1H-pyrrol-3(2H)-ones.