Synthesis and spectroscopic studies of 2‐(1,1‐dimethylhydrazono)propyl phosphonates

The synthesis of diethyl 2‐(1,1‐dimethylhydrazono)propyl phosphonate (1) and its 1‐benzoyl derivative (2) is described. The 1 H and 13 C NMR spectra of 1 and 2 have been completely assigned with the aid of two‐dimensional 1 H 13 C correlation NMR spectroscopy. Spectral data for ethyl α‐benzoyl‐β‐(1,1‐dimethylhydrazino)crotonate (5) were also obtained. The results show that 1 exists predominantly in the E ‐ and Z ‐isomeric forms in a ratio of ca 2:1, and 2 occurs almost exclusively in the E ‐form. Data for 5 indicate that this compound exists in the Z ‐ and E ‐forms in a ratio of ca 3:1.