Synthesis and anticancer potential of certain novel 2-oxo-N'-(2-oxoindolin-3-ylidene)-2H-chromene-3-carbohydrazides.

Treatment of ethyl 3-hydrazinyl-3-oxopropanoate (6) with indoline-2,3-dione derivatives 7a-g gave ethyl 3-oxo-3-(2-(2-oxoindolin-3-ylidene)hydrazinyl)propanoates 8a-g which were allowed to react with the appropriate salicyaldehyde 9a and/or 9b to furnish the chromene-based hydrazones 10a-i. Compounds 10a-i displayed a significant activity against HT-29 colon cancer cell line and a moderate activity against leukemia K562 cell line. Compound 10f emerged as the most active congener toward HT-29 colon cancer cell line with IC₅₀ = 7.98 ± 0.05 μM whereas compound 10c exhibited the best antiproliferative activity against leukemia K562 cell line with IC₅₀ = 9.44 ± 0.02 μM. Moreover, compound 1e showed 87.81 ± 7% inhibition of side population (SP) HT-29 colon cancer stem cells.