Diastereoselective Synthesis of New Dialkylphosphorylhydrazones

Abstract

A series of 22 dialkylphosphorylydrazones (dialkyl ester, N′-[(1E)-(R1 phenyl)methylene]-phosphorohydrazidic acid), 20 of them new, along with three new N,N′-bis (diisobutylphosphorylthioamide)diamines (bis-[diisobutyl ester), N-thioxomethylene]-, diamine)phosphora-midic acid, were prepared and characterized by IR, 1H NMR, 13C NMR, 31P NMR, and mass spectrometry. The analysis of 1H NMR, 13C NMR, 31P NMR, and NOE spectra confirmed the observation of the single diastereoisomer E in the synthesis of dialkylphosphorylydrazones. The results of a molecular modeling study performed in order to investigate the mechanism of the synthesis of dialkylphosphorylydrazones are in agreement with the experimental results, i.e., the favored formation of diastereoisomer E over Z.