Benzo[b] thiophene derivatives XVII. Electrophilic substitution of 4‐hydroxybenzo[b] thiophene derivatives

Abstract

A variety of eleclrophilic substitution reactions have been carried out on 4‐methoxybenzo[b]‐thiophene (IIIa) and 4‐benzoyloxybenzo[b ] thiophene (IVa). Substitution occurs in the 7‐position of IIIa and, with the exception of bromination, in the 7‐position of IVa. Bromination of IVa occurs in the 3‐position. Bromination of 4‐hydroxybenzo[b] thiophene (IIa) occurs in the 5‐position. The nmr spectra of eleven disubstituted benzo[b] thiophenes have been tabulated.