Synthesis of ß-tropolone and fused heterocycle derivatives by acid-catalyzed and photoreactions of o-quinones with quinolines and benzimidazoles

Abstract

The condensation of 3,5-di-(tert-butyl)-1,2-benzoquinone 1 with 2-methylquinolines 2 proceeding on refluxing o-xylene solutions of the components in the presence of catalytic amounts of p-toluenesulfonic acid gives rise to previously unknown β-tropolones 3. In the case of quinolines 2 containing amino or nitro groups in position 4, the reaction with quinone 8 also leads to the formation of derivatives of a novel heterocyclic system of 2-azabicyclo[3.