2-Benzopyrylium salts containing thiophene substituents in positions 1 and 3

2-Benzopyrylium salts containing heterocyclic substituents have not previously been known. In order to obtain 2-benzopyrylium salts containing thiophene substituents in position 3, we have studied the acylation of 3,4-dimethoxybenzyl 2-thienyl ketone (I), which was obtained with a yield of 36% by the acylation of thiophene (at 75° C) with homoveratric acid in the presence of polyphosphoric acid (PPA). Compound I forms yellow crystals with mp 74–75° C (from benzene), bp 220° C (6mm). Found %: C 63.40; H 5.38; S 13.55. C₁₁H₁₃O₃S. Calculated %: C 64.12; H 5.34; S13.21.Translated from Khimiya Geterotsiklicheskikh Soedinenii.Vol. 6, No. 7, pp. 1003–1004, July, 1970.