One Pot Synthesis of α-Aminophosphonates Containing Bromo and 3,4,5-Trimethoxybenzyl Groups under Solvent-free Conditions

Abstract: New α-aminophosphonates were synthesized by the Kabachnik-Fields reactionof 3,4,5-trimethoxybenzaldehyde (TMB) with p- or m-bromoaniline and a dialkylphosphite under solvent-free conditions. TMB was prepared from gallic acid via a fourstep synthetic sequence involving etherification, esterification, hydrazidation andpotassium ferricyanide oxidation. The structures of all synthesized compounds wereconfirmed by elemental analysis, IR, ¹H-, ¹³C- and ³¹P-NMR spectral data. Compound 7gwas also characterized by X-ray crystallography. A half-leaf method was used todetermine the in vivo curative efficacy of the eight title products against tobacco mosaicvirus (TMV). It was found that compounds 7g and 7h possess good in vivo curativeeffects against TMV.