A simple and catalyst free one pot access to the pyrazolone fused 2,8-dioxabicyclo[3.3.1]nonanes

Abstract

Synthesis of a series of novel aryl and heteroaryl fused 2,8-dioxabicyclo[3.3.1]nonanes (<bold>3</bold>) was accomplished by one pot, catalyst free reaction of 2-hydroxy chalcones (<bold>1</bold>) with 3-trifluoromethyl substituted pyrazolones (<bold>2</bold>) in xylene at reflux temperature. The role of –CF₃ in formation of <bold>3</bold> was confirmed by comparing with 3-methyl pyrazolones.