In the title compound, C 24 H 24 N 2 O 6 , the mean planes of the pyran rings (A and B) are inclined to one another by 69.2 (1) , while the aromatic ring (D) of the chromene ring system makes dihedral angles of 63.42 (11) and 66.81 (12) with the pyrimidine (C) and benzene (E) rings, respectively. Pyran ring A has an halfchair conformation, while pyran ring B has an envelope conformation, with the spiro C atom as the flap. In the crystal, molecules are linked by C-HÁ Á ÁO hydrogen bonds, forming a supramolecular three-dimensional network. There are also a number of C-HÁ Á Á interactions present. Structure descriptionChromenes are used in the fields of medicine, cosmetics and as fluorescent dyes. 2-Oxo-2H-chromenes are efficient fluorophores characterized by good emission quantum yields and are used as materials for lasers in organic light-emitting devices, non-linear optical chromeophores and fluorescent labels (Sreenivasa et al

The asymmetric unit of the title compound, C17H10Cl4O, consists of one independent molecule and two molecules each located on twofold symmetry axes through the central C=O bond such that they each contribute half a molecule each to the asymmetric unit. The dihedral angles between the rings in the three molecules are 73.1 (3), 65.3 (3) and 75.4 (3)°. In the crystal, molecules are linked through C—H...O hydrogen bonds, generating undulated molecular sheets lying parallel to (110).

In the title compound, C41H41N3O9·2.25H2O, the cyclohexanol ring adopts a chair conformation. The cyclohexanol ring makes dihedral angles of 87.89 (7) and 75.53 (8)° with the mean planes of the trimethoxyphenyl rings and dihedral angles of 84.18 (8), 85.07 (7) and 82.03 (8)° with the pyridine rings. In the crystal, the packing is stabilized by C—H...O, O—H...O and O—H...N hydrogen bonds involving water molecules and methoxy O atoms, resulting in a supramolecular network. One of the methoxy groups is disordered over two sets of sites with occupancy factors of 0.63 (3) and 0.37 (3).