| abstract |
The present invention relates to a process for the preparation of thieno[3,2-c]pyridine or thieno[2,3-c]pyridine, comprising cyclizing a N-(3-thienyl)-methyl-N-[ 2,2-(OR)2]ethyl-para-toluene sulfonamide or a N-(2-thienyl)-methyl-N-[2,2-(OR)2]ethyl-para-toluene sulfonamide, respectively, in which R is lower alkyl or both R groups form together a 2- or 3-membered alkylene radical, by treatment with an acid in the presence of an inert organic solvent. |