Synthesis of Novel bis-Phosphonate Derivatives by Pudovik Reaction

Synthesis of novel bis-(3-methyl-5-nitro-2-oxo-2,3-dihydro-2λ ⁵benzo1,3,2]oxazaphosphol-2yl)substituted aryl methanes was accomplished by Pudovik reaction. Addition of equimolar quantities of 2-methylamino-4-nitro phenol (1) and ethanol to PCl₃ afforded cyclic condensation product. On reaction with respective aldehydes followed by treatment with phosphorus(III) monochloride of 1, and on subsequent reaction at reflux temperature, this rearranged from P(III) to P(V) state. Their structures were determined by IR, ¹H NMR, ¹³C NMR, ³¹P NMR, and mass spectral data.