Synthesis and anticancer activity of isatin-based pyrazolines and thiazolidines conjugates

The synthesis and antitumor activity screening of novel isatin based conjugates with thiazolidine and pyrazoline moieties were performed. Reaction of 3,5-diaryl-4,5-dihydropyrazoles with chloroacetyl chloride yielded starting 2-chloro-1-(3,5-diaryl-4,5-dihydropyrazol-1-yl)-ethanones which were utilized in alkylation of isatin and 5-bromoisatin. Thus, corresponding 1-[2-(3,5-diaryl-4,5-dihydropyrazol-1-yl)-2-oxoethyl]-1H-indole-2,3-diones (1a-1d) have been obtained. The compounds 1a-1d have been used in Knoevenagel condensation with 4-thiazolidinones for obtaining a series of 5-ylidenederivatives 2a-2f and 3a-3d. The synthesized compounds were tested for their anticancer activity in NCI60 cell lines. Among the tested compounds, 5-bromo-1-{2-[5-(4-chlorophenyl)-3-(4-methoxyphenyl)-4,5-dihydropyrazol-1-yl] -2-oxoethyl}-1H-indole-2,3-dione (1d) was found to be the most active candidate with selective influence on leukemia subpanel tumor cell lines with GI ₅₀ values range of 0.69-3.35 μM. Hybrid compounds were synthesized by linking the main structural unit of the isatin ring system with the pyrazoline and 4-thiazolidinone and their in-vitro antitumor activity was examined.