5-Amino-3-methyl-1,2-oxazole-4-carbonitrile.

In the title compound, C(5)H(5)N(3)O, the isoxazole ring is essentially planar, with a maximum deviation of 0.007 (1) Šfrom the least-squares plane. The N atom of the amine group exhibits sp(2) character (sum of bond angles around this atom = 358°). In the crystal, mol-ecules are aggregated by two kinds of N-H⋯N hydrogen bonds into fused R(2) (2)(12) and R(6) (6)(26) rings, forming a slightly puckered two-dimensional array lying parallel to (101).

N,N'-Dibenzyl-N''-(2,4-difluoro-benzo-yl)-N,N'-dimethyl-phospho-ric triamide.

In the title mol-ecule, C(23)H(24)F(2)N(3)O(2)P, the P atom is in a distorted tetra-hedral P(=O)(N)(N)(2) environment, with the bond angles around the P atom in the range 106.78 (11)-114.10 (13)°. The phosphoryl and carbonyl groups, which are separated by an N atom, adopt an anti orientation relative to each other. In the C(=O)NHP(=O) fragment, the P-N bond is longer [1.683 (2) Å] and the O-P-N angle is smaller [106.78 (11)°] than the other P-N bonds [1.613 (2) and 1.632 (2) Å] and O-P-N bond angles [114.10 (13) and 110.83 (12)°], respectively. The N atoms have sp(2) character. In the crystal, pairs of P=O⋯H-N hydrogen bonds form inversion dimers with R(2) (2)(8) ring motifs.

N,N'-Dibenzyl-N,N'-dimethyl-N''-(2-phenyl-acet-yl)phospho-ric triamide.

The P atom in the title mol-ecule, C(24)H(28)N(3)O(2)P, is in a distorted tetra-hedral P(=O)(N)(N)(2) environment. The phosphoryl group and the NH unit adopt a syn orientation with respect to each other and the N atoms have sp(2) character. The P-N bonds in the P(O)[N(CH(3))(CH(2)C(6)H(5))](2) unit are shorter than the P-N bond in the C(=O)NHP(=O) fragment. An intra-molecular C-H⋯O hydrogen bond occurs. In the crystal, pairs of P=O⋯H-N hydrogen bonds form centrosymmetric dimers. C-H⋯O contacts are also observed. Four C atoms of two benzene rings are disordered over two alternative sites with an occupancy ratio of 0.523 (12):0.427 (12).

N,N'-Dicyclo-hexyl-N''-(3-fluoro-benzo-yl)-N,N'-dimethyl-phospho-ric triamide.

In the title compound, C(21)H(33)FN(3)O(2)P, the P atom has a distorted tetra-hedral environment and the N atoms display geometries consistent with a model of sp(2) hybridization (with bond-angle sums for the tertiary N atoms of 357.8 and 358.7°). The phosphoryl and carbonyl groups are anti with respect to each other. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R(2) (2)(8) loops.

N-(3-Fluoro-benzo-yl)-N',N''-bis-(4-methyl-phen-yl)phospho-ric triamide.

In the title compound, C(21)H(21)FN(3)O(2)P, the NH and P(=O) groups of the C(=O)NHP(=O) fragment are in a syn arrangement with respect to each other, as are the two amide H atoms of the two CH(3)-4-C(6)H(4)-NH moieties. In the crystal, mol-ecules are linked through N-H⋯O(=P) and N-H⋯O(=C) hydrogen bonds, forming R(2) (2)(8) and R(2) (2)(12) rings, which are arranged in chains parallel to [010].