Chemistry of condensed thiophenes. III. Acetylation of triphenyleno [1,12-bcd]thiophene

Friedel-Crafts reaction of triphenyleno1,12-bcd]thiophene (2) by means of aluminum chloride, nitrobenzene, and a limited excess of acetyl chloride yielded 3-acetyl-2 (78%) and 3,5-diacetyl-2 (7%). Use of a large excess of acetyl chloride gave yields of 42% and 22%, respectively. Wolff-Kishner reduction of the acetyl compounds produced 3-ethyl-2 (15%) and 3,5-diethyl-2 (8%). Structures were assigned largely on the basis of ¹H nmr and ultraviolet absorption spectra of the products.