Furazans and furazan oxides. Part II. Preparation and tautomerism of some acyl furoxans; examples of steric hindrance to conformational mobility in alicyclic six-membered rings

Abstract

The dihydrobenzofurazan-4-one 1-oxides (10a)–(15a) are converted almost completely into the isomeric 3-oxides (10b)–(15b), respectively, on heating. Rate and equilibrium constants for the reaction have been determined. Some chemical transformations of the ketones are described. The dihalogeno-ketones (13) and (14)(a and b) display broadened n.m.r. signals at room temperature, due to slow equilibration between the ‘half-chair’ conformers.