N-(5-Nitro-1,3-thiazol-2-yl)-4-(trifluoromethyl)benzamide

There are two independent and conformationally dissimilar molecules (A and B) in the asymmetric unit of the title compound, C11H6F3N3O3S; the dihedral angles between the benzene and thiazole rings are 33.8 (2)° in A and 59.7 (2)° in B. The similarity of the C—N bond lengths in the amide group [1.379 (5) and 1.358 (5) Å for A, and 1.365 (5) and 1.363 (5) Å for B] indicates the presence of conjugation between the two rings. In the crystal, molecules are linked by N—H⋯N hydrogen bonds, forming chains extending along [010]; weak N—H⋯Oamide interactions are also present in the structure.

There are two independent and conformationally dissimilar molecules (A and B) in the asymmetric unit of the title compound, C 11 H 6 F 3 N 3 O 3 S; the dihedral angles between the benzene and thiazole rings are 33.8 (2) in A and 59.7 (2) in B. The similarity of the C-N bond lengths in the amide group [1.379 (5) and 1.358 (5) Å for A, and 1.365 (5) and 1.363 (5) Å for B] indicates the presence of conjugation between the two rings. In the crystal, molecules are linked by N-HÁ Á ÁN hydrogen bonds, forming chains extending along [010]; weak N-HÁ Á ÁO amide interactions are also present in the structure.

N-(5-Nitro-1,3-thiazol-2-yl)-4-(trifluoromethyl)benzamide
Xi-Wang Liu, Han Zhang, Ya-Jun Yang, Jian-Yong Li and Ji-Yu Zhang Comment Parasitic and bacterial infections represnt a significant cause of morbidity and mortality worldwide (Fox & Saravolatz, 2005). Nitazoxanide is a novel antiparasitic compound developed for both human and animal use and is the parent compound of a class of drugs named thiazolides. Recently, a number of thiazolides were synthesized and their biological activities were also evaluated (Gargala et al., 2010);Stachulski et al., 2011). The title compound C 11 H 6 F 3 N 3 O 3 S is a new thiazolide which displays higher antibacterial activity than nitazoxanide (Ballard et al., 2011) and the crystal structure is reported herein.
In this structure, there are two independent and conformationally dissimilar molecules in the asymmetric unit ( Fig. 1) [dihedral angles between the benzene and thiazole rings: 33.8 (2) and 59.7 (2)°]. In the crystal, the molecules are linked by intermolecular N-H···N hydrogen bonds (Table 2), giving one-dimensional chains extending along [010]. Also present in the structure are intra-and intermolecular N-H···O amide interactions within the chains.
The similarity of the C-N bond lengths [N1-C8, 1.379 (5) Å and N1-C9, 1.358 (5) Å] in the amide group indicates the presence of conjugation between the two rings, which confirms the hypothetical mechanism with thiazolides that the amin anion may interact with the target PFOR enzyme.

Experimental
To a solution of 5-nitrothiazol-2-amine (1 mmol) in distilled pyridine was added a equimolar amount of 4-trifluorobenzoyl chloride with stirring. After the addition was complete, the reaction mixture was allowed to stand overnight. The reaction was judged complete by TLC analysis. The crude product that separated on dilution was filtered, washed with 10% sodium bicarbonate solution, then several times with water. The dry solid was purified by chromatography to give the pure title compound and crystals suitable for single crystal X-ray analysis were obtained by recrystallization from methanol.

Refinement
The positions of all H atoms were determined geometrically and refined using a riding model with C-H = 0.93 Å and N -H = 0.86 Å and with U iso (H) = 1.2U eq (C, N).  The molecular conformation and atom numbering scheme for the two independent molecules in the asymmetric unit of title compound, with displacement ellipsoids drawn at the 30% probability level.

N-(5-Nitro-1,3-thiazol-2-yl)-4-(trifluoromethyl)benzamide
Crystal data  Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 > σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 0.2871 (