Stereochemistry as a Determinant of the Anti-Leukemic Potency of Halopyridyl and Thiazolyl Thiourea Compounds

Chiral derivatives of two cyclohexylethyl halopyridyl thiourea compounds (HI-509 and HI-510), two α -methyl benzyl halopyridyl compounds (HI-511 and HI-512), and a cyclohexyl ethyl thiazolyl thiourea compound (HI-513) were synthesized and evaluated for their anti-cancer activity. Preliminary screening indicated that the (S)- isomers displayed improved activity in comparison with (R)- enantiomers to inhibit tubulin polymerization and activate caspase- 3. In accordance with these results, the thiourea derivatives displayed potent anti-cancer activity against human B-lineage (Nalm-6) and T-lineage (Molt-3) acute lymphoblastic leukemia cell lines. Based on the results we conclude that the anti-leukemic activity of these compounds also depends on their chirality.