ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Claisen condensation of dimethyl 2,3-thiophenedicarboxylate with methyl acetate and acetonitrile

M. Struhárik and P. Hrnčiar

Department of Organic Chemistry, Faculty of Natural Sciences, Komenský University, CS-S42 15 Bratislava

Abstract: Claisen condensation of dimethyl 2,3-thiophenedicarboxylate with methyl acetate has been carried out. It was found that practically only the first step of the reaction proceeded on the carbon of the methoxycarbonyl group in the position 2 of the thiophene ring, while 4,5-dihydro-6H-cycIopenta[/?]thiophe- ne-4,6-dione (II) was formed only in a low yield. Higher yields of ß-diketone (II) were not achieved by changing the reaction conditions. Also the reaction with acetonitrile proceeded on the carbon of the methoxycarbonyl group in the position 2 of the thiophene ring and the cyclic product has not been isolated. The compounds obtained were characterized by their IR, 'H NMR, and n C NMR spectra.

Full paper in Portable Document Format: 393a391.pdf

Chemical Papers 39 (3) 391–400 (1985)