Isomerization of 2-seleno-1,3,2-diazaphospholidine derivatives

For the first time the isomerization of 1,3,2-diazaphospholidine-2-selenide derivatives in refluxing benzene in the presence of trace water was observed, and the structure of isomerized product was determined by X-ray diffraction, IR, ¹H NMR, ³¹P NMR, and elemental analysis. The mechanism of isomerization was also proposed. The isomerized phosphoroheterocycle (C₂₆H₃₈N₃O₅PSe, Mr = 582.52) is orthorhombic with space group Pbca, a = 17.1010(9) Å, b = 16.6404(9) Å, c = 20.7517(11) Å, V = 5905.3(5) ų, Z = 8, Dr = 1.310 g/cm³, λ = 0.71073 Å, μ (Mo Kα) = 1.363 mm^?1, F(000) = 2432. The structure was refined to R1 = 0.0482, wR2 = 0.1204 for 5214 unique reflections with I > 2σ(I). Intramolecular and intermolecular hydrogen bonds are observed in the crystal packing.