Abstract
Some novel pyrazoline derivatives bearing thiazole and thiophene moieties have been efficiently synthesized and characterized. The synthetic approach involves condensation of 5-acetylthiazole
1
with 2-formyl thiophene
2
followed by heterocyclization of the produced chalcone
3
with hydrazine and thiosemicarbazide under different conditions to give selectively 1-substituted-3-(thiazol-5-yl)-5-(thiophen-2-yl)pyrazolines
4
–
6
and
8
in high yields. Heterocyclization of 1-thicarbomylpyrazoline
8
with 3-chloro-2,4-pentanedione, phenacyl bromide and hydrazonoyl bromides in boiling ethanol and TEA results in the respective 1-(thiazol-2-yl)-3-(thiazol-5-yl)-5-(thiophen-2-yl)pyrazolines
11
,
12
, and
14a
–
14f
. Anticancer activity of the novel 1,3,5-trisubstituted pyrazolines has been evaluated, against breast (MCF-7), liver (HepG2), and colon (HCT-116) cancer cell lines, as well as epithelial (REP1) normal cell line. Among the synthesized pyrazolines, compounds
8
,
14a
, and
14f
demonstrate the highest anticancer activity with IC
50
values of 1.83, 5.47, and 11.43 µM, respectively, and presenting no evidence of human toxicity.