Synthesis and anticancer evaluation of novel isoxazole/pyrazole derivatives

The key intermediate 3-amino-5-methylisoxazole (1) was allowed to react with phthalic anhydride and/or maleic anhydride under different conditions to produce different isoxazole products. Schiff bases 9a–c obtained via the reaction of 1 with different aldehydes were condensed with thioglycolic acid to afford the corresponding thiazolidin-4-one derivatives 10a, b. Furthermore, condensation of the Schiff bases 9a, c with various secondary amines produced the corresponding 5-substituted pyrazole derivatives 11a–d, respectively. The anticancer activity of some of the newly synthesized compounds was evaluated against Panc-1 and Caco-2 cell lines using doxorubicin as a standard drug. Most of the tested derivatives exhibited high cytotoxic potency against Panc-1 carcinoma cell lines, but moderate to weak activity was obtained against Caco-2 cell lines.