Abstract
Diazotization of 2-aminothiophenes la-c with NaNO2/HCl gave the diazonium salts 2a-c which coupled with 3-iminobutanenitrile in ethanol/sodium acetate to achieve the corresponding hydrazones 3a-c. Compounds 3a-c achieved 3-aminopyrazoles 4a-c on refluxing with hydrazine hydrate in ethanol. Furthermore, compound 2a coupled with malononitrile in ethanol and in the presence of sodium acetate to give the hydrazonomalononitrile 5 which refluxed with hydrazine hydrate to give 3, 5-diaminopyrazole 6. Moreover, the intermediate 2b coupled with 1-phenyl-2-thiocyanatoethanone in ethanol/sodium acetate to afford the corresponding hydrazone 7 which reacted with malononitrile to give thiazole 8. On the other hand, compound 8 was prepared through coupling of 2b with thiazole 9. Condensation of 8 with hydrazine hydrate in ethanol gave diaminopyrazole 10. Most of the new synthesized compounds exhibited good antitumor activities.
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