A novel and expedient approach to new heterocycles containing benzothiophene, benzothieno[2,3-d] pyrimidine and coumarin moieties

In order to obtain potent protein-tyrosine kinase inhibitors, a novel and versatile method for synthesis of heterocyclic compounds 4a-d and 5a-c comprising 2-imino-2H-1-benzopyran, tetrahydrobenzo[b]thiophene, and carboxamide/1H-benzimidazole fragments has been developed. This method was based on the reactions of 2-imino-2H-1-benzopyrans 1a,b and 2 with 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophenes 3a-c in glacial acetic acid. Furthermore, new heterocycles 8a,b with tetrahydrobenzo[4,5]thieno[2,3-d] pyrimidine and coumarin moieties have been synthesized via a rearrangement of the corresponding 2-(tetrahydrobenzo[b]thien-2-yl)imino-2H-1-benzopyran-3-carboxamides 4a,b. (C) 1999 Elsevier Science Ltd. All rights reserved.