Selective nucleophilic replacement of the benzylsulfanyl group in 2,4‐disulfanyl‐substituted thieno[2,3‐d]pyrimidin‐6‐carboxylic acid derivatives by secondary amines

Thieno2,3‐d]pyrimidines with benzylsulfanyl and allylsulfanyl group in the presence of other alkylsul‐fanyl substituents react selectively under mild conditions with secondary amines under replacement of the benzyl or allyl residue whereas the other substituents remain intact. This enables the synthesis of different basic substituted derivatives with potentially biologically activity.