An orthorhombic polymorph of 2-(1,3-benzothiazol-2-yl)-6-ethoxyphenol

In the title molecule, C15H13NO2S, an intramolecular O—H⋯N hydrogen bond forms an S(6) ring motif. The benzothiazole ring system and the benzene ring form a dihedral angle of 8.9 (3) Å. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds, forming chains along the b axis. In addition, π–π interactions [centroid–centroid distances = 3.772 (4) and 3.879 (4) Å] are observed.

In the title molecule, C 15 H 13 NO 2 S, an intramolecular O-HÁ Á ÁN hydrogen bond forms an S(6) ring motif. The benzothiazole ring system and the benzene ring form a dihedral angle of 8.9 (3) Å . In the crystal, molecules are linked by weak C-HÁ Á ÁO hydrogen bonds, forming chains along the b axis. In addition,interactions [centroid-centroid distances = 3.772 (4) and 3.879 (4) Å ] are observed.

Experimental
The title compound was synthesized by adding 3-ethoxysalicylaldehyde (2 mmol) to a solution of 2-aminothiophenol (2mmol) in ethanol (30 ml). The mixture was refluxed with stirring for half an hour. The resultant solution was filtered.
Light-yellow prismatic single crystals of the title compound suitable for X-ray structure determination were recrystallized from ethanol by slow evaporation of the solvent at room temperature over several days.

Refinement
The O-bound H atom was located in a difference Fourier map and constrained to refine on the parent atom with U iso (H) = 1.5U eq (O). The other H-atoms were included in calculated positions and treated as riding atoms: C-H = 0.93, 0.97 and 0.96 Å for CH, CH 2 and CH 3 H-atoms, respectively, with U iso (H) = k × U eq (C), k = 1.2 for CH, CH 2 and 1.5 for CH 3 .

2-(1,3-Benzothiazol-2-yl)-6-ethoxyphenol
Crystal data C 15 H 13 NO 2 S M r = 271.32 Orthorhombic, P2 1 2 1 2 1 Hall symbol: P 2ac 2ab a = 4.8728 (10)  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.19 e Å −3 Δρ min = −0.30 e Å −3 Absolute structure: Flack (1983), 874 Friedel pairs Flack parameter: −0.1 (2) Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.