Thermal functionalisation of nitrogen substituents: formation of dihydropyrrol-3-ones, quinolin-4-ones, and enaminoenaminones by gas-phase hydrogen transfer reactions

Abstract

Pyrolysis of the aminomethylene Meldrum's acid derivatives (5-aminomethylene-2,2-dimethyl-1,3-dioxane-4,6-dione)(1), (7), (11), and (12) causes hydrogen transfer reactions which result in specific functionalisation of the amino substituent: tertiary amino substrates give 1,2-dihydropyrrol-3-ones (60%) by ring closure, while secondary amino substrates give quinolin-4-ones (90%) or enaminoenaminones (90%).