1,2-Bis(1,3-benzothiazol-2-yl)benzene

The title compound, C20H12N2S2, was prepared by the reaction of o-phthalic acid and 2-aminothiophenol under microwave irradation. The phenyl ring, A, and the benzothiazolyl rings, B and C, are planar; the dihedral angles are A/B = 19.9 (11), A/C = 87.8 (3) and B/C = 84.4 (4)°. Weak intermolecular C—H⋯N hydrogen bonds link the molecule, forming zigzag chains parallel to the c axis.

The title compound, C 20 H 12 N 2 S 2 , was prepared by the reaction of o-phthalic acid and 2-aminothiophenol under microwave irradation. The phenyl ring, A, and the benzothiazolyl rings, B and C, are planar; the dihedral angles are A/B = 19.9 (11), A/C = 87.8 (3) and B/C = 84.4 (4) . Weak intermolecular C-HÁ Á ÁN hydrogen bonds link the molecule, forming zigzag chains parallel to the c axis.

Comment
Benzothiazole are remarkable heterocyclic ring systems. They have been found to exhibit a wide spectrum of biological activities. They have shown antitumor,antimalarial,and fungicide activity. They are also an important class of industrial chemicals. Many kinds of 2-substituted benzothiazoles are utilized as vulcanization accelators in the manufacture of rubber,as fluorescent brightening agents in textile dyeing,and in the leather industry (Chakraborti et al.,2004;Seijas et al.,2007). There are numerous synthetic methods to produce 2-arylbenzothiazoles. The most important ones include the reaction of o-aminothiophenols with benzoic acids or their derivatives (Chakraborti et al.,2004;Seijas et al.,2007). Microwave-assisted organic synthesis (MAOS) is a powerful technique that is being used more and more to accelerate thermal organic reactions (Kappe & Stadler, 2005). We are focusing on Microwave-assisted synthesis of new products of bisbenzothiazole. We here report the crystal structure of the title compound (I).

Refinement
All H atoms were positioned geometrically, with C-H = 0.96 and 0.97 Å for methyl and methylene H atoms, and constrained to ride on their parent atoms, with U iso (H) = xU eq (C), where x= 1.5 for methyl H and x = 1.2 for methylene H atoms.
supplementary materials sup-2 Figures   Fig. 1. A view of the molecular structure of (I) with the atom-numbering scheme. Ellipsoids are drawn at the 50% probability level. H atoms are represented as small spheres of arbitrary radii.

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 > σ(F 2 ) is used only for calculating Rfactors(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.