3-(6-Methyl-2-pyrid-yl)-2-phen-oxy-3,4-dihydro-1,3,2-benzoxaza-phosphirine 2-oxide.

In the title compound, C(19)H(17)N(2)O(3)P, the six-membered 1,3,2-oxaza-phospho-rine ring adopts a twist-boat conformation with the phosphoryl O atom in an equatorial position. The P=O(oxide) bond length is 1.457 (1) Šand the average value of the P-O distances is 1.588 Å. The crystal structure is stabilized by C-H⋯O and C-H⋯π inter-actions.

Diethyl [(4-bromo-phen-yl)(5-chloro-2-hydroxy-anilino)meth-yl]phospho-nate.

In the title compound, C(17)H(20)BrClNO(4)P, inter-molecular C-H⋯O and N-H⋯O hydrogen bonds form centrosymmetric R(2) (2)(10) dimers linked through O-H⋯O inter-molecular hydrogen bonds, which form centrosymmetric R(2) (2)(16) dimers. All these hydrogen bonds form chains along [010]. In addition, the crystal structure is stabilized by weak C-H⋯Br hydrogen bonds. The very weak intramolecular N-H⋯O interaction forms a five-membered ring.

2,4,8,10,13-Penta-methyl-6-phenyl-13,14-dihydro-12H-6λ-dibenzo[d,i][1,3,7,2]dioxaza-phosphecin-6-thione.

In the title compound, C(25)H(28)NO(2)PS, the cyclo-decene ring exhibits a crown conformation. The two dimethyl-benzene rings which are fused symmetrically on either side of the ten-membered ring, make dihedral angles of 20.2 (1) and 18.0 (1)°. The phenyl ring substituted at P is perpendicular to the heterocyclic ring, making a dihedral angle of 88.4 (1)°. The crystal structure is stabilized by very weak intra-molecular C-H⋯O hydrogen bonding.