New approaches for the synthesis of thiophene derivatives with anti-tumor activities.

The reaction of either cyclohexanone or cyclopentanone with cyanoacetylhydrazine and elemental sulfur gave the 2-aminocycloalkeno[b]thiophene derivatives 3a and 3b, respectively. The latter compounds reacted with either aromatic benzaldehydes or active methylene reagents to give the Schiff's bases 5a-d and the pyrazole derivatives 7a-d and 9a-d, respectively. On the other hand, the reaction of 3-oxo-N-p-tolylbutanamide (10) with either of malononitrile or ethyl cyanoacetate gave the thiophene derivatives 13a and 13b, respectively. Compounds 13a,b were subjected to a series of heterocyclization reactions to give heterocyclic derivatives. Their cytotoxicity against the three human tumor cells lines, namely breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and CNS cancer (SF-268) together against the normal human cell line namely the normal fibroblast cells WI 38 were measured.