4-(4-Chlorophenyl)-6-hydroxy-5-(2-thienylcarbonyl)-6-(trifluoromethyl)-3,4,5,6-tetrahydropyrimidin-2(1H)-one monohydrate

The asymmetric unit of the title compound, C16H12ClF3N2O3S·H2O, contains two crystallographically independent organic molecules and two water molecules. The organic species are linked by an intermolecular O—H⋯O hydrogen bond, while the water molecules are connected to them through intermolecular O—H⋯N hydrogen bonds. The thiophene and phenyl rings are oriented at dihedral angles of 62.35 (4) in the first independent molecule and 60.74 (5)° in the second, while the pyrimidine rings adopt twisted conformations in both molecules. Intramolecular N—H⋯F interactions result in the formation of two five-membered rings having envelope conformations. In the crystal structure, further intermolecular O—H⋯O and N—H⋯O hydrogen bonds link the molecules into chains.

The asymmetric unit of the title compound, C 16 H 12 ClF 3 -N 2 O 3 SÁH 2 O, contains two crystallographically independent organic molecules and two water molecules. The organic species are linked by an intermolecular O-HÁ Á ÁO hydrogen bond, while the water molecules are connected to them through intermolecular O-HÁ Á ÁN hydrogen bonds. The thiophene and phenyl rings are oriented at dihedral angles of 62.35 (4) in the first independent molecule and 60.74 (5) in the second, while the pyrimidine rings adopt twisted conformations in both molecules. Intramolecular N-HÁ Á ÁF interactions result in the formation of two five-membered rings having envelope conformations. In the crystal structure, further intermolecular O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds link the molecules into chains.

S1. Comment
In recent years, several modified and improved procedures for one-pot synthesis of dihydropyrimidine-2(1H)-ones have been reported (Paraskar et al., 2003;Peng & Deng, 2001). However, in spite of their potential utility, many of these methods suffer from drawback like longer reaction times, unsatisfactory yields and cumbersome product isolation procedures. We report herein the synthesis and crystal structure of the title compound.
The asymmetric unit of the title compound contains two crystallographically independent molecules and two water molecules ( Fig. 1 ), in which the bond lengths (Allen et al., 1987) and angles are within normal ranges. Rings A (S1/C1-  (Table 1) link the two molecules, while the water molecules are connected to them through the intramolecular N-H···O hydrogen bonds (Table 1).
In the crystal structure, intermolecular O-H···O and N-H···O hydrogen bonds (Table 1) link the molecules into chains ( Fig. 2), in which they may be effective in the stabilization of the structure.

S3. Refinement
H atoms of water molecules and OH groups were located in difference Fourier map and refined isotropically. The remaining H atoms were positioned geometrically with N-H = 0.86 Å (for NH) and C-H = 0.93 and 0.98 Å, for aromatic and methine H atoms, respectively, and constrained to ride on their parent atoms, with U iso (H) = 1.2U eq (C,N).  The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.  A partial packing diagram of the title compound viewed down the a axis. Hydrogen bonds are shown as dashed lines.