Synthesis, spectral characterization and bioassay of 3,3'-(1,4-phenylene)-bis[2-alkoxycarbonyl-alkyl)-2-thio-benzoxa-phosphinines].

Synthesis of 3,3'-(1,4-phenylene)-bis[2-alkoxycarbonyl-alkyl)-2-thio-benzoxaphos-phinines] (3a-j) were accomplished via two step process. It involves the prior preparation of monochloride intermediate (2) and its subsequent reaction with the amino acid esters in dry tetrahydrofuran-toluene in the presence of triethylamine at reflux temperature. These compounds were characterized by IR, 1H, 13C, 31P NMR and were found to exhibit potent in vitro antioxidant activity.