(2E)-2-(1,3-Benzothiazol-2-yl)-3-(dimethylamino)prop-2-enenitrile

The molecular conformation of title compound, C12H11N3S, is almost planar [maximum deviation = 0.063 (2) Å]; an intramolecular C—H⋯N hydrogen bond is noted. In the crystal, molecules interact with each other via π–π stacking interactions between thiazole rings [centroid–centroid distance = 3.7475 (9) Å] and methyl-H⋯π(C6) interactions, forming columns along the a axis.


Comment
It is well known that the thiazolyl group is of great importance in biological systems. In recent years, there has been considerable interest in the synthesis of substituted benzothiazolyl compounds due to their pharmacological properties such as anti-fungal (Selvam et al., 2011;Sanja & Cvetkovic, 2011), anti-viral (Alang et al., 2010;Pal et al., 2011), antibacterial (Sharma et al., 2010;El-Shaaer et al., 1997), analgesic (Gupta & Raat, 2010), anti-tumour (Hutchinson et al., 2002) and anti-tuberculosis (Gong et al., 2004;Hutchinson et al., 2003) activities. Moreover, such compounds have been also found to have a potent local anaesthetic activity (Geronikaki & Theophilidis, 1992;Vicini et al., 1990). Antiinflammatory, analgesic, and anti-pyretic activities for some thiazolyl and benzothiazolyl derivatives are also known (Das et al., 2003;Klose et al., 1983;Satsangi et al., 1983). Based on the above and following to our ongoing studies in synthesis of bio-active heterocyclic compounds the title compound has been prepared as a precursor for further study.
As shown in Fig. 1, title compound (I) has an almost planar conformation for non-hydrogen atoms with a maximum deviation of -0.063 (2) Å for C6.

Experimental
A mixture of 1,3-benzothiazol-2-ylacetnitrile (174 mg, 1 mmol) and dimethylformamide-dimethylacetal (119 mg, 1 mmol) were taken in acetic acid (10 ml). The reaction mixture was refluxed and monitored by TLC until completion after 8 h. The reaction mixture was allowed to cool at ambient temperature and poured into ice water. The solid product was collected by filtration and recrystallized from ethanol to afford the title compound in 88% yield. Single crystals suitable for X-ray analysis were grown up on slow evaporation of ethanolic solution of the title compound at room temperature over three days. M.pt: 441-443 K.

Refinement
All H-atoms were refined using a riding model with C-H = 0.93 Å and U iso =1.2 eq (C) for aromatic-H atoms, and C-H = 0.96 Å and U iso = 1.5U eq (C) for methyl-H atoms.

Figure 2
The molecular packing of the title compound viewing along the a axis. All H atoms are omitted for clarity. Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses 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 observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs 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.