Synthesis and crystal structure of 2-phosphonoalkyl-1, 2-benzisoselenazol-3(2H)-ones and their antitumor activities

The title compounds were synthesized in good yields by the condensation reaction of diphenyl α-aminoalkylphosphonates with 2-(chloroseleno)-benzoyl chloride. Their structures were confirmed by spectroscopic methods and microanalyses. The X-ray analyses showed that the selenium-containing fused ring has a planar structure and that, by the molecular packing of the unit cells, two adjacent molecules are symmetrically linked to each other through Se(1c) ... O=P(1) bonding interactions with an intermolecular Se(1c) ... O distance of 2.797 Å. The results of bioassay indicated that some of these compounds possess potent antitumor activities against some human carcinoma cells in vitro.