Synthesis and antimicrobial activity of 2-(substituted)-3-(6-methyl-2-pyridyl)-3,4-dihydro-2H-1,3,25-benzoxazaphosphinin-2-ones, thiones and selones

2-(substituted)-3-(6-methyl-2-pyridyl)-3,4-dihydro-2H-1,3,2e5-benzoxazaphosphinin- 2-ones (5a-d) were synthesized by reaction of 2-{[(6-methyl-2- pyridyl) amino]methyl} phenol (1)with various aryl phosphorodichloridates (4) in the presence of triethylamine at 45-50°C. The title compounds (5e-h) were synthesized via an intermediate monochloride route. The compounds (8a-f) have been synthesized in two steps by the condensation of (1) with dichlorophenyl phosphine/ethyldichlro phosphite followed by reactionwith hydrogen peroxide, sulfur and selenium respectively.