Jul-Aug 1982 Monomethyl Isomers of Benzo[o]naphtho[l,2-c/]thiophene 873 were readily prepared from o- and /»-methylbenzenethiol via the method of Tilak (5). However, in the case of m-methylbenzenethiol, this reaction gave a mixture of 4-methyl- and 6-methylbenzo[6]thiophene -2-carbox- aldehyde (34 and 35). When this mixture was allowed to react with 30 in a similar manner, a mixture of two styryl compounds, 4-methyl- and 6-methyl-2-styrylbenzo[6]thio- ...