2-{[3-Methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl]methylsulfanyl}-1H-benzimidazole monohydrate: a monoclinic polymorph

The title compound, C16H14F3N3OS·H2O, which had been previously characterized in the space group P-1 [Ren et al. (2011 ▶). Acta Cryst. E67, o270], has now been crystallized from 1-propanol in the monoclinic form in the space group P21/c. While the triclinic form is a Z′ = 2 crystal, the new monoclinic polymorph includes one main molecule and one water lattice molecule in the asymmetric unit. In the crystal, the water molecule is sandwiched between neighboring main molecules and behaves as both donor and acceptor in O—H⋯N and N—H⋯O hydrogen bonds with the imidazole N atoms. This pattern of chains parallel to [100] further interacts via O—H⋯N(pyridine) contacts.

The title compound, C 16 H 14 F 3 N 3 OSÁH 2 O, which had been previously characterized in the space group P1 [Ren et al. (2011). Acta Cryst. E67, o270], has now been crystallized from 1-propanol in the monoclinic form in the space group P2 1 /c. While the triclinic form is a Z 0 = 2 crystal, the new monoclinic polymorph includes one main molecule and one water lattice molecule in the asymmetric unit. In the crystal, the water molecule is sandwiched between neighboring main molecules and behaves as both donor and acceptor in O-HÁ Á ÁN and N-HÁ Á ÁO hydrogen bonds with the imidazole N atoms. This pattern of chains parallel to [100] further interacts via O-HÁ Á ÁN(pyridine) contacts.   Table 1 Hydrogen-bond geometry (Å , ). Symmetry codes: (i) Àx þ 1; Ày þ 1; Àz þ 1; (ii) Àx; Ày þ 1; Àz þ 1.

Related literature
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL. The title compound is the critical reaction intermediate for the synthesis of lansoprazole (Del Rio et al., 2007;Reddy et al., 2008), and its analogs, used as drugs for their anti-ulcer effects (Iwahi et al., 1991). Recently, the compound was successfully crystallized from 1-propanol, and the crystal structure is reported here. A first polymorph was X-ray  (Fig. 2). The water molecule could thus be considered to be a hydrogen-bond bridge, which provides stability to the crystal lattice. The hydrogen bond characteristics and geometric parameters are given in Table 1.
The geometry of the main molecule is close to that reported for analog systems (Hakim Al-arique et al., 2010;Swamy & Ravikumar, 2007).

Experimental
The raw material was kindly provided by Shanghai Enran Sci-Tech Investment Management Co., Ltd. The compound was dissolved in 1-propanol and suitable crystals were obtained by slow evaporation at room temperature over a period of one week.

Refinement
Water H atoms were initially located in a difference map and then fixed in their as-found positions, while all other H atoms were constrained to an ideal geometry with C-H distances of 0.93 Å (aromatic CH), 0.96 Å (methyl CH 3 ), 0.97 Å (methylene CH 2 ) and N-H distance of 0.86 Å (imidazolic NH). Isotropic displacement parameters for H atoms were calculated as U iso (H) = xU eq (carrier atom) with x = 1.5 (H 2 O and methyl group) or x = 1.2 (other H atoms).

Computing details
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97  The content of the asymmetric unit of the title hydrate with displacement ellipsoids drawn at the 30% probability level. H atoms have been omitted for clarity.

Figure 2
A packing diagram of the title compound. Supramolecular chains are running in the [100] direction, and dashed bonds indicate secondary hydrogen bonds connecting the chains in the crystal.