N-(4,6-Dimethylpyrimidin-2-yl)-1,3-benzothiazol-2-amine

In the title compound, C13H12N4S, an amino N atom is connected to a 1,3-benzothiazole fused-ring system and a dimethyl-substituted pyrimidine ring, these components being aligned [interplanar dihedral angle = 1.9 (1)°]. The secondary amino N atom forms an intermolecular N—H⋯N hydrogen bond to an N atom of the fused ring of an adjacent molecule, generating a centrosymmetric cyclic hydrogen-bonded dimer [graph set R 2 2(8)].

In the title compound, C 13 H 12 N 4 S, an amino N atom is connected to a 1,3-benzothiazole fused-ring system and a dimethyl-substituted pyrimidine ring, these components being aligned [interplanar dihedral angle = 1.9 (1) ]. The secondary amino N atom forms an intermolecular N-HÁ Á ÁN hydrogen bond to an N atom of the fused ring of an adjacent molecule, generating a centrosymmetric cyclic hydrogen-bonded dimer [graph set R 2 2 (8)].
The use of the EPSRC X-ray crystallographic facilities at the University of Southampton, England, is gratefully acknowledged. We thank Manchester Metropolitan University, Sohag University and the University of Malaya for supporting this study.

Comment
In an earlier study, we reported the structure of N-(4,6-dimethylpyrimidin-2-yl)-1H-benzimidazol-2-amine (Mohamed et al., 2011). The benzimidazole portion of that molecule was replaced by a benzothiazole unit in the present study, giving the title compound C 13 H 12 N 4 S (Scheme I). In this molecule, an amino N atom is connected to a benzothiazole fused-ring system and a dimethyl-substituted pyrimidine ring, these being aligned [inter-ring dihedral angle, 1.9 (1)°] (Fig. 1). The amino N atom forms an intermolecular N-H···N hydrogen bond to the N atom of the fused-ring of an adjacent molecule (Table 1) to generate a centrosymmetric cyclic hydrogen-bonded dimer [graph set R</i<> 2 2 (8) (Etter et al., 1990)].
Experimental 2-(1,3-Benzothiazol-2-yl)guanidine (0.05 mol) was heated in acetylacetone solution (0.10 mol, approx. 10 ml) in the presence of a few drops of acetic acid at 473 K for 1 h. The mixture was cooled and the product was collected and recrystalized from ethanol to give the title compound (m.p. 513 K) in 85% yield.

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H, 0.95 to 0.98 Å) and were included in the refinement in the riding model approximation, with U iso (H) set to 1.2 to 1.5U eq (C). The amino H-atom was located in a difference Fourier map, and was freely refined. The reflections (-1 2 3) and (0 1 2) were omitted because to bad agreement. Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of C 13 H 12 N 4 S at the 70% probability level. Hydrogen atoms are drawn as spheres of arbitrary radius.