6-Methoxy-3-methylbenzofurano-4,7-quinone; dimers of 3-methylbenzofurans; and tautomerism in 2-acetyl-3-hydroxy-5-methoxy-1,4-benzoquinone

Abstract

The synthesis of 6-methoxy-3-methylbenzofurano-4,7-quinone is described. Structures are deduced for the dimers, obtained in the preparation of 4,6,7-trimethoxy- and 4-hydroxy-6-methoxy-3-methylbenzofurans, and also for the trimer obtained in the cyclisation of 3,5-dimethoxyphenoxyacetone.

2-Acetyl-3-hydroxy-5-methoxy-1,4-benzoquinone, prepared in several ways, is shown by nuclear magnetic resonance spectroscopy to be in equilibrium with its 1,2-quinonoid tautomer in deuteriochloroform.