6-Chloro-3-phenethyl-2-thioxo-2,3-dihydroquinazolin-4(1H)-one

The asymmetric unit of the title quinazolinone compound, C16H13ClN2OS, consists of two crystallographically independent molecules, A and B. The dihedral angles between the quinazoline and benzene rings are 16.88 (6) and 32.34 (6)° for molecules A and B, respectively. In the crystal structure, molecules A and B are linked by two bifurcated intermolecular N—H⋯S and C—H⋯S hydrogen bonds. Pairs of molecules are further linked by C—H⋯O and C—H⋯Cl hydrogen bonds into a chain aligned approximately along [110].

The asymmetric unit of the title quinazolinone compound, C 16 H 13 ClN 2 OS, consists of two crystallographically independent molecules, A and B. The dihedral angles between the quinazoline and benzene rings are 16.88 (6) and 32.34 (6) for molecules A and B, respectively. In the crystal structure, molecules A and B are linked by two bifurcated intermolecular N-HÁ Á ÁS and C-HÁ Á ÁS hydrogen bonds. Pairs of molecules are further linked by C-HÁ Á ÁO and C-HÁ Á ÁCl hydrogen bonds into a chain aligned approximately along [110].
The asymmetric unit of the title quinazolinone compound, (I), consists of two crystallographically independent molecules, A & B (Fig. 1). The quinazoline rings are essentially planar with maximum derivations of 0.034 (1) Å for atom N1A, and 0.049 (1) Å for atom C8B. The dihedral angles between the quinazoline and benzene rings are 16.88 (6) and 32.34 (6)°f or molecules A and B, respectively.

Experimental
The title compound (I) was synthesized according to a modification of the method of Butler & Partridge (1959). Equimolar amounts of 2-amino-5-chlorobenzoic acid and 2-phenylethyl isothiocyanate in acetic acid (6 ml) were mixed and stirred under reflux at 423 K for 90 min. The solid that formed was the pure thiol (yield 76.7 %) which produced colourless crystals upon recrystallization from 99.5% ethanol.

Refinement
The H2NA and H2NB atoms were located from difference Fourier map and refined freely. The remaining H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 or 0.97 Å. and with U iso (H) = 1.2 U eq (C). Fig. 1. The molecular structure of (I) with displacement ellipsoids at the 50% probability level for non-H atoms. supplementary materials sup-3

Figures
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 Rfactors(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.