Synthesis, Structural Elucidation, and In Vitro Antitumor Activities of Some Pyrazolopyrimidines and Schiff Bases Derived from 5-Amino-3-(arylamino)-1H-pyrazole-4-carboxamides

The reaction of 5-amino-3-(arylamino)-1H-pyrazole-4-carboxamides 1a,b with acetylacetone 2 and arylidenemalononitriles 5a–c yielded the pyrazolo[1,5-a]-pyrimidine derivatives 4a,b and 7a–f respectively. On the other hand, Schiff bases 9a,b and 12a–j were obtained upon treatment of carboxamides 1a,b with isatin 8 and some selected aldehydes 11a–e. The newly synthesized compounds were characterized by analytical and spectroscopic data. Representative examples of the synthesized products 4a,b, 7e, 7f, 9b, 12b–f, 12h, and 12j were screened for their in vitro antitumor activities against different human cancer cell lines and the structure-activity relationship (SAR) was discussed.