Synthesis, X-ray crystallographic analysis, and antitumor activity of N-(benzothiazole-2-yl)-1-(fluorophenyl)-O,O-dialkyl-α-aminophosphonates

α-Aminophosphonates containing benzothiazole and fluorine moiety, 4a–4m, were synthesized by Mannich-type addition in ionic liquid media with high yield and short reaction time. Their structures were established by IR, 1H NMR, 13C NMR, and elemental analysis. The X-ray crystallographic data of compounds 4j and 4m were provided. The newly synthesized compounds were evaluated for their anticancer activities against PC3, A431, A375, and Bcap37 cells in vitro by the MTT method. Compound 4c is highly effective against PC3 cells and moderate to A431 cells. Hence, further study is necessary to find out the potential antitumor activities.