3-Acetyl-1-(4-methylphenyl)thiourea

The asymmetric unit of the title compound, C10H12N2OS, contains two independent molecules. In both molecules, the conformations of the two N—H bonds are anti to each other. Furthermore, the conformations of the amide C=S bonds and the C=O bonds are anti to each other. The dihedral angles between the benzene ring and the side chain are 52.8 (1) and 68.0 (1)° in the two independent molecules. An intramolecular N—H⋯O hydrogen bond occurs in both independent molecules. In the crystal, molecules are linked into infinite chains along the a axis through a series of N—H⋯O and N—H⋯S hydrogen bonds.

The asymmetric unit of the structure contains two independent molecules. The conformations of the two N-H bonds in the side chain are anti to each other and one of them is anti to the C═S in the urea segments and the other is syn, in both the molecules, similar to the anti conformation observed in 3-acetyl-1-(2-methylphenyl)thiourea (Shahwar et al., 2012) Further, the conformations of the amide C═S and the C═O are anti to each other.
The amide oxygen and one of the NH hydrogen atoms exhibit both intra-and inter-molecular bifurcated hydrogen bonding. In the structure, series of N-H···O and N-H···S intermolecular hydrogen bonds pack the molecules into infinite chains (Table 1, Fig.2).

Experimental
3-Acetyl-1-(4-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 4-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.
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 = 0.93 Å and methyl C-H = 0.96 Å. 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 supplementary materials sup-2 Acta Cryst. (2012). E68, o2128 parent atom. In one of the two crystallographically independent molecules the H atoms of both methyl groups are disordered and were refined using a split model.   Molecular packing of the title compound with hydrogen bonding shown as dashed lines.

3-Acetyl-1-(4-methylphenyl)thiourea
Crystal data C 10 H 12 N 2 OS M r = 208.28 Triclinic, P1 Hall symbol: -P 1 a = 9.1623 (8)   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.