Methyl N-(dimethoxyphosphoryl)carbamate

In the title compound, CH3OC(O)NHP(O)(OCH3)2, the P atom has a slightly distorted tetrahedral configuration. The mixed imide moiety can be described as cisoid–transoid in which the two opposing dipoles (P=O and C=O) are oriented with a O=C⋯P=O torsion angle of 150.88(18)°. In the crystal, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers.

In the title compound, CH 3 OC(O)NHP(O)(OCH 3 ) 2 , the P atom has a slightly distorted tetrahedral configuration. The mixed imide moiety can be described as cisoid-transoid in which the two opposing dipoles (P O and C O) are oriented with a O CÁ Á ÁP O torsion angle of 150.88(18) . In the crystal, molecules are linked by pairs of N-HÁ Á ÁO hydrogen bonds, forming inversion dimers.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: GG2115).  (Sokolov et al. 2008). Many of these compounds also show biological activity (Amirkhanov et al. 1996, Rebrova et al. 1984, Tsibulskaya et al. 1956). This work reports the structure of methyl(dimethoxyphosphoryl)carbamate (I) (C 4 H 10 NO 5 P).
In the title compound (I), the phosphorus atom has a slightly distorted tetrahedral configuration. The average values of the angles OPN and OPO in the molecule are close to the tetrahedral, with the exception O3-P1-O4 and O1-P1-O4, which can be explained by interaction of nucleophilic carbonyl oxygen atom O2 with electrophilic phosphorus atom P1, corresponding distance less than the sum of the Van der Waals Radii 3.3 Å. There is repulsion between the oxygen atoms O2 and O4 distorting the tetrahedral environment of the phosphorus atom, the O···O distance is less than the sum of the Van der Waals radii 3.04 Å. Short O···O interactions have also been reported for dinitramide anion (Zhurova et al., 2002) and dimanganese decacarbonyl (Bianchi et al., 2000).
The O1 and O4 atoms are adjacent to it with deviations of 0.453 (3) Å and 0.582 (3) Å, respectively. The P=O bond has an angle of deviation from this plane of 23.4 (2)°.

Experimental
All chemicals were commercial products of reagent grade, used without further purification. Methyl(dimethoxyphosphoryl)carbamate (I) was prepared as in (Kirsanov et al. 1959). Single crystals of (I) were prepared by slow crystallization from benzene solution.

Refinement
The H atoms bonded to C and N were located in differnce Fourier maps but subsequently introduced in calculated positions and treated as riding on their parent atoms (C or N) with C-H = 0.98 Å with U iso (H) = 1.5 and N-H = 0.86 Å with U iso (H) = 1.2 U eq .

Figure 1
A view of the title compound showing the atom-numbering scheme and displacement ellipsoids drawn at the 30% probability level.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.