Synthesis of novel 5-(3-alkylquinolin-2-yl)-3-aryl isoxazole derivatives and their cytotoxic activity.

The propargyl alcohol on reaction with aldoxime and NaOCl in DCM gave exclusively (3-arylisoxazol-5-yl) methanol 1. The compound 1 was oxidized to an aldehyde 2 followed by reaction with aniline resulted in Schiff's base 3. The compounds 3 were further reacted with various aldehydes having α-hydrogen using molecular iodine as catalyst and which yielded 5-(3-alkylquinolin-2-yl)-3-aryl isoxazole derivatives 4. All the final compounds 4 were screened against four human cancer cell lines (A549, COLO 205, MDA-MB 231 and PC-3) and among these compounds 4n showed potent cytotoxicity against all the cell lines at IC50 values of <12 μM.