Comments on a novel synthesis of diethyl 1-aminoarylmethylphosphonates on the surface of alumina

Contrary to the literature statement we found that aromatic aldehydes react with diethyl phosphite and hexamethyldisilazane to give 1-(trimethylsilyloxy)-1-arylmethylphosphonates and not 1-amino-1-arylmethylphosphonate derivatives. Therefore, for preparation of diethyl N-arylidene-1-amino-1-arylmethylphosphonate, we recommend the direct reaction of hydrobenzamides with diethyl phosphite, instead of aromatic aldehydes, hexamethyldisilazane and alumina as catalyst on solid phase, as has been described previously (Sardarian, A. R.; Kaboudin, B. Tetrahedron Lett. 1997, 38, 2543–2546).