Synthesis and properties of novel α-phosphoryl(thio)ureido alkanephosphonate derivatives

Two series of novel α-phosphoryl(thio)ureido alkanephosphonate derivatives (5,6) have been synthesized by a convenient, multistep route involving the addition reaction of phosphoryl isothiocyanides with α-aminoalkanephosphonates and a homogeneous desulphurisation utilizing Ag⁺-H₂O system as key steps. The carbodiimide intermediate 8 in the conversion of compounds 5 into 6 was trapped to afford regioselectively the corresponding imino-ether 9 instead of its isomer 10. All the compounds prepared were confirmed by ¹H NMR, IR, MS, ³¹P NMR and elemental analysis. Preliminary bioassays indicate that compounds 5 and 6 have potent antiphytoviral activities against the tobacco mosaic virus (TMV). In addition, some of 5 possess selective herbicidal activities and some of 5 and 6 exhibit good fungicidal activities against wheat leaf rust and cucumber grey blight.