Synthesis and Spectroscopic Investigation of 4-Methylphenyl Esters of Dimethyl Phosphoramidochloridic Acid and Dimethyl Phosphoramidofluoridic Acid

Synthesis of 4-methylphenyl esters of N,N-dimethyl phosphoramidochloridic acid (1) and N,N-dimethyl phosphoramidofluoridic acid (2) is reported. 18-Crown-6 with potassium fluoride was found an effective reagent for the conversion of 1 to 2. These compounds were characterized by using 1H, 31P NMR, infrared and mass spectroscopic data. Analysis of the 1H NMR spectrum of ester 1 gives a long-range 31P-1H spin spin coupling (7 J P-H = 1.2 Hz). A possible explanation for this unusual seven-bond coupling is discussed. In this study, a reasonable correlation between 31P chemical shifts and P=O vibration frequencies is suggested.