Process for the production of thiophenes from alpha-methylene ketones in the single-stage process and new ortho-fused thiophenes produced by means of the process

Described is a novel process which can be carried out as a single-stage synthesis for the production of substituted and/or b,d- ortho-fused thiophenes. Serving as starting compounds and α-methylene ketones which are reacted in an preferably alcoholic solvent with bromine whereafter the formed intermediate product after separation from the solvent is reacted directly with a sulphurising agent. Preferably under reflux conditions in a suitable solvent to form the end product. In this way also hitherto unknown ortho-fused thiophene compounds are synthesized more especially those with 5 or 9 rings condensed with one another.