Dialkyl-N-alkoxy-N-(4-toluenesulfonyl)phosphoramidates: synthesis and structure

This study investigates the reaction between N-alkoxy-N-chloro-4-toluenesulfonamides and N-chloro-N-(methoxy)methanesulfonamide with trialkyl phosphites, resulting in the formation of dialkyl N-alkoxy-N-(4-toluenesulfonyl)phosphoroamidates and dialkyl N-methoxy-N-methanesulfonylphosphoroamidates, respectively. The resulting dialkyl N-alkoxy-N-(4-toluenesulfonyl)phosphoramidates and N-alkoxy-N-methanesulfonylphosphoramidates are identified as products of nucleophilic substitution at the amide nitrogen atom. The structures of these compounds have been confirmed by ¹H, ³¹P, and ¹³C NMR spectroscopy, mass spectrometry, and an XRD study. The XRD study of dimethyl N-methoxy-N-(4-toluenesulfonyl)phosphoroamidate and dimethyl N-ethoxy-N-(4-toluenesulfonyl)-phosphoroamidate reveals a pyramidal configuration at the amide nitrogen atom, along with the shortening of the N–O(Alk) bond and the elongation of the N–P and N–S bonds. In the asymmetric part of the unit cell, dimethyl N-ethoxy-N-(4-toluenesulfonyl)phosphoramidate exists in the form of two independent molecules that differ in the degree of pyramidality of the nitrogen atom and the lengths of its bonds.