Diethyl {(4-methoxy­phen­yl)[5-(4-nitro­phen­yl)-1,3,4-thia­diazol-2-ylamino]meth­yl}phospho­nate

The title compound, C(20)H(23)N(4)O(6)PS, was synthesized by the reaction of N-(4-methoxy­benzyl­idene)-5-(4-nitro­phen­yl)-1,3,4-thia­diazol-2-amine and diethyl phosphite. The thia­diazole and nitro-substituted phenyl rings in the mol­ecule are approximately coplanar, the dihedral angle being 5.3 (2)°. The dihedral angle formed by the mean plane through all non-H atoms of both the thia­diazole and the nitro-substituted phenyl ring with the plane of the meth­oxy-substituted phenyl ring is 48.9 (2)°. In the crystal structure, mol­ecules form centrosymmetric dimers as a result of N—H⋯O bonds involving amine H and phosphine oxide O atoms.