3-Acetyl-1-(3-methylphenyl)thiourea

In the crystal structure of the title compound, C10H12N2OS, the conformation of the two N—H bonds are anti to each other. The amide C=O and the C=S are are also anti to each other. The N—H bond adjacent to the benzene ring is syn to the m-methyl groups. The dihedral angle between the benzene ring and the side chain [mean plane of atoms C—C(O)N—C—N; maximum deviation 0.029 (2) Å] is 14.30 (7)°. There is an intramolecular N—H⋯O hydrogen bond generating an S(6) ring motif. In the crystal, the molecules are linked via N—H⋯) hydrogen bonds, forming chains propagating along [001]. The S atom is disordered and was refined using a split model [occupancy ratio 0.56 (4):0.44 (4)].

BTG thanks the University Grants Commission, Government of India, New Delhi, for a special grant under the UGC-BSR one-time grant to faculty.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RK2375).
The conformation of the two N-H bonds are anti to each other. The adjacent N-H bond is syn to the m-methyl group in the benzene ring, compared to the anti conformation observed between the N-H bond and the o-methyl group in the benzene ring in 3-acetyl-1-(2-methylphenyl)thiourea, I, (Shahwar et al., 2012). Furthermore, the conformation of the amide C═O and the C═S are anti to each other, similar to that observed in I.
The side chain is oriented itself with respect to the phenyl ring with the torsion angles of C2-C1-N1-C7 = -168.76 (14)° and C6-C1-N1-C7 = 14.71 (24)°. The dihedral angle between the phenyl ring and the side chain The amide oxygen exhibits a bifurcated hydrogen bonding by showing the simultaneous intra-and intermolecular hydrogen bonding generating S(6) and C(4) motifs. In the crystal of the title compound, the molecules are linked via N-H···S hydrogen bonds with an R 2 2 (12) motif and N-H···O hydrogen bonds with a C(4) motif into a layered structure ( Experimental 3-Acetyl-1-(3-methylphenyl)thiourea was synthesized by adding a solution of acetyl chloride (0.10 mol) in acetone (30 ml) dropwise to a suspension of ammonium thiocyanate (0.10 mol) in acetone (30 ml). The reaction mixture was refluxed for 30 min. After cooling to room temperature, a solution of 3-methylaniline (0.10 mol) in acetone (10 ml) was added and refluxed for 3 h. The reaction mixture was poured into acidified cold water. The precipitated title compound was recrystallized to constant melting point from acetonitrile. The purity of the compound was checked and characterized by its infrared spectrum. The characteristic absorptions observed are 3163.7 cm -1 , 1690.0 cm -1 , 1269.5 cm -1 and 693.3 cm -1 for the stretching bands of N-H, C═O, C-N and C═S, respectively.
Prism like yellow single crystals used in X-ray diffraction studies were grown in acetonitrile solution by slow evaporation of the solvent at room temperature.

Refinement
H atoms bonded to C were positioned with idealized geometry using a riding model with the aromatic C-H = 0.93Å, methyl C-H = 0.96Å. The amino H atoms were freely refined with the N-H distances restrained to 0.86 (2)Å. All H atoms were refined with isotropic displacement parameters set at 1.2 U eq (C-aromatic, N) and 1.5 U eq (C-methyl) of the The S atom is disordered and was refined using a split model. The corresponding s.o.f.'s were refined so that their sum was unity: 0.56 (4) and 0.44.

Special details
Experimental. CrysAlis RED (Oxford Diffraction, 2009) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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.