Benzo[B]thiophene derivatives XXIV. Oxidation of o-dihydroxybenzo[b]thiophene methyl ethers

The attempted oxidative demethylation of a series of o-dihydroxybenzob]thiophene methyl ethers with cerium (IV), argentic oxide, periodale and thallate usually led to intractable mixtures. However, in one ease, use of ceric ammonium nitrate resulted in nitration of the benzob]-thiophene ring. In another example, treatment with aqueous periodate or thallate resulted in oxidative hydroxylation of benzob]thiophene.