Syntheses of heterocyclic compounds. Part XXXIII. Preparation and reactions of 4-(2-dialkylaminophenyl)azetidin-2-ones

Abstract

2-Dialkylaminobenzylideneanilines and various acid chlorides in presence of triethylamine were used to obtain the novel title compounds. Those β-lactams with an α-chloro-substituent underwent intramolecular cyclisation involving the dialkylamino-group with expulsion of the chlorine atom to give β-lactams bearing a fused indolinium system. Thermolysis of these fused β-lactams afforded various N-alkylindoles (with elimination of phenyl iso-cyanate). Aspects of stereochemistry, substituent effect, and alkaline or acidic hydrolysis of the fused β-lactams which lead to novel indole derivatives are described.