Substitution reactions of benzo[b]thiophen derivatives. Part VI. Reactions of 4-methoxybenzo[b]thiophen and its 3-methyl derivative

Abstract

The bromination, nitration, Vilsmeier–Haack formylation, and Friedel–Crafts acetylation reactions of 4-methoxy-benzo[b]thiophen and its 3-methyl derivative have beeen investigated. For 4-methoxybenzo[b]thiophene, these reactions gave the 7-substituted product, whereas for the 3-methyl derivative a mixture of the 2-(ca. 40%) and 7-substituted compounds (ca. 60%) was obtained in each case. For both compounds, dibromination and dinitration gave the 2,7-disubstituted derivative. The structures of the substitution products were determined by n.m.r. spectroscopy.