A total of 53 N-benzoylated phenoxazines and phenothiazines, including their S-oxidized analogues, were synthesized and evaluated for antiproliferative activity, interaction with tubulin, and cell cycle effects. Potent inhibitors of multiple cancer cell lines emerged with the 10-(4-methoxybenzoyl)-10 H-phenoxazine-3-carbonitrile (33b, IC50 values in the range of 2– 15 nM) and the isovanillic analogue 33c. Seventeen compounds strongly inhibited tubulin ...
