Cleavage of the methylenedioxy group with sodium methoxide in dimethyl sulfoxide.

Abstract

The methylenedioxy ring in piperonal (1) and its 6-substituted derivatives (5, 6, 9, and 10) was opened by heating with sodium methoxide in dimethyl sulfoxide to give the phenolic products, isovanillin (4) and its 6-substituted derivatives (7, 8, 11, and 12), respectively. Similarly, the nitro compounds (16 and 19) gave phenolic products (17 and 20, respectively) by this method. However, the ring in the compounds having methyl (compound 21), carboxyl (compound 22), methoxycarbonyl (compound 23), and amide (compound 24) groups instead of the formyl group in 1 could not be opened by this method.