1-[5-Acetyl-4-(4-bromophenyl)-2,6-dimethyl-1,4-dihydropyridin-3-yl]ethanone monohydrate

The 1,4-dihydropyridine ring in the title hydrate, C17H18BrNO2·H2O, has a flattened-boat conformation, and the benzene ring is occupies a position orthogonal to this [dihedral angle: 82.19 (16)°]. In the crystal packing, supramolecular arrays mediated by N—H⋯Owater and Owater—H⋯Ocarbonyl hydrogen bonding are formed in the bc plane. A highly disordered solvent molecule is present within a molecular cavity defined by the organic and water molecules. Its contribution to the electron density was removed from the observed data in the final cycles of refinement and the formula, molecular weight and density are given without taking into account the contribution of the solvent molecule.

The 1,4-dihydropyridine ring in the title hydrate, C 17 H 18 BrNO 2 ÁH 2 O, has a flattened-boat conformation, and the benzene ring is occupies a position orthogonal to this [dihedral angle: 82.19 (16) ]. In the crystal packing, supramolecular arrays mediated by N-HÁ Á ÁO water and O water -HÁ Á ÁO carbonyl hydrogen bonding are formed in the bc plane. A highly disordered solvent molecule is present within a molecular cavity defined by the organic and water molecules. Its contribution to the electron density was removed from the observed data in the final cycles of refinement and the formula, molecular weight and density are given without taking into account the contribution of the solvent molecule.
VV is grateful to the DST-India for funding through the Young Scientist Scheme (Fast Track Proposal).
The aryl ring is orthogonal to the 1,4-dihydropyridine ring with a dihedral angle between their respective least-squares planes of 82.19 (16) °. The observed conformation in (I) is entirely consistent with those found for the two closely related aryl derivatives of (I), i.e. with PhNO 2 -3 (Rathore et al., (2009) and with PhOH-4, as the monohydrate (de Armas et al., 2000). The difference between the structures relate to the relative disposition of the acetyl groups. In each case, these are essentially co-planar with the 1,4-dihydropyridine ring and in the PhNO 2 -3 derivative (Rathore et al., (2009), both carbonyl atoms are orientated away from the amine group whereas in (I) and in PhOH-4 monohydrate (de Armas et al., 2000), one is orientated towards the amine group.
The crystal packing features N-H···O water and O water -H···O carbonyl hydrogen bonding, Table 1. These link the molecules into a layer in the bc plane, Fig. 2, with all the aryl rings being orientated to one side of the plane for each layer. Pairs of layers interdigitate to form sandwich structure, Fig. 3.
The remaining H were located from a difference map and refined with O-H = 0.840±0.001 (with H1w···H2w = 1.39±0.01) and N-H = 0.880±0.001, and with U iso (H) = nU eq (parent atom), with n = 1.5 for O and n = 1.2 for N. Unresolved disordered solvent was evident in the final cycles of the refinement. This was modelled with the SQUEEZE option in PLATON (Spek, 2009); the solvent cavity had volume 251 Å 3 . In the final cycles of refinement, this contribution to the electron density was removed from the observed data. The density, the F(000) value, the molecular weight, and the formula are given without taking into account the contribution of the solvent molecule(s). The structure factor programme detects differences in R values. These discrepancies arise as the structure factor checking program does not take into account the SQUEEZE procedure applied to the data, as explained in the refinement section, and appended at the end of the CIF. Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 35% probability level.