{2-[(1,3-Benzothiazol-2-yl)methoxy]-5-fluorophenyl}(4-chlorophenyl)methanone

The asymmetric unit of the title compound, C21H13ClFNO2S, contains two independent molecules with similar conformations. In the molecules, the thiazole ring is essentially planar [maximum atomic deviations = 0.014 (4) and 0.023 (5) Å] and is oriented with respect to the fluorophenyl ring and chlorophenyl rings at 9.96 (18) and 70.39 (18)° in one molecule and at 7.50 (18) and 68.43 (18)° in the other; the dihedral angles between the fluorophenyl and chlorophenyl rings are 64.9 (2) and 64.6 (2)°, respectively. Intermolecular C—H⋯O and C—H⋯F hydrogen bonds stabilize the three-dimensional supramolecular architecture. Weak C—H⋯π and π–π interactions [centroid–centroid distance = 3.877 (3) Å] lead to a criss-cross molecular packing along the c axis.

Substituted benzothiazole derivatives exhibit various pharmacological properties such as analgesic, antimicrobial, antidepressant, antitumor, antihypertensive, anthelmintic, and herbicidal activity (Kelarev et al., 2003). Thus the biological features of new benzothiazole derivatives is of great scientific interest (Telvekar et al., 2012;Saeed et al., 2010;Rana et al., 2007). Several crystal structures of the benzothiazoles have been reported (Nayak et al., 2013;Venugopala et al., 2012). Here, we report the single-crystal structure of the title compound.

Experimental
To a solution of (2-chloromethyl)benzo[d]thiazole (1 mmol) and (4-chlorophenyl)(5-fluoro-2-hydroxyphenyl)methanone (1 mmol) in dry THF, dry potassium carbonate (1 mmol) was added and stirred at room temperature. The reaction mixture was added and the reaction mixture was stirred at room temperature for 14 h. The reaction mixture was concentrated to remove the solvent, diluted with ethyl acetate, washed with water, brine solution and dried over anhydrous sodium sulfate. The organic layer was concentrated to yield a residue which was purified by column chromatography using ethyl acetate and n-hexane as eluent (7:3, Rf = 0.70) to afford the product in 78% as a white solid (m. p. 419 (2) K). Suitable crystals for single-crystal X-ray study were obtained from acetone solvent using slow evaporation technique at room temperature.

Refinement
All H atoms were positioned geometrically and refined using a riding model with U iso (H)= 1.2 U eq (C).  (Nardelli, 1995).

Figure 1
Molecular structure shows the atom labelling scheme with displacement ellipsoids for non-H atoms at 30% probability level, hydrogen atoms are arbitrary circle.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.