Abstract: | Oxodihydrocyclopentathiophenacetic acids 4 , 5 and 6 were synthesized from suitable 2- or 3-formylthiophenes. Reactivity of the carbonyl group or the carboxylic group of these bicyclic systems was investigated. The Beckmann rearrangement of methyl 6-oximino4,5-dihydro-6H-cyclopentab]thiophen-4-acetate 12 is an interesting route to methyl 7-oxo-4,5,6,7-tetrahydrothieno2,3-c]pyridin-4-acetate ( 13 ). |