Thiophen derivatives. Part XXII. Preparation of naphtho[2′,3′:4,5]-thieno[3,2-b][1]benzothiophen and some methyl homologues
Abstract
The Friedel–Crafts condensation of thieno[3,2-b][1]benzothiophen with some mono- and di-methyl homologues of benzoyl chloride, and of thieno[3,2-b][1]benzcthiophen-2-carbonyl chloride with m- and p-xylene, afforded a series of ketones which underwent Elbs pyrolysis to furnish naphtho[2′,3′:4,5]thieno[3,2-b][1]benzothiophen and three of its methyl homologues.