1-Benzoyl-3-(naphthalen-1-yl)thiourea

In the title compound, C18H14N2OS, the dihedral angle between the mean planes of the 3-naphthyl and 1-benzoyl rings is 20.7 (1)°. The crystal packing is stabilized by weak N—H⋯S interactions. Intramolecular N—H⋯O and C—H⋯O hydrogen bonding is also observed.

In the title compound, C 18 H 14 N 2 OS, the dihedral angle between the mean planes of the 3-naphthyl and 1-benzoyl rings is 20.7 (1) . The crystal packing is stabilized by weak N-HÁ Á ÁS interactions. Intramolecular N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonding is also observed.
JPJ acknowledges the NSF-MRI program (grant NoÁCHE1039027) for funds to purchase the X-ray diffractometer.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FK2043).

Comment
Thioureas are the subject of significant interest because of their usefulness in medicinal chemistry due to their biological activity as fungicides (Saeed et al., 2010a), anticancer (Saeed et al., 2010b),herbicides, rodenticides and phenoloxidase enzymatic inhibitors (Maddani & Prabhu, 2010). Recently, thiourea derivatives have found use in organocatalysis (Jung & Kim, 2008). Amino-thiourea derivatives (Saeed et al., 2009) and their transition metal complexes are used as curing agents for epoxy resins (Saeed et al., 2011). Thioureas have a long history as a ligand in coordination chemistry and coordinate readily to a metal via sulfur and oxygen (Burrows et al., 1999). These hard and soft donor atoms provide a multitude of bonding possibilities (Henderson et al., 2002). Hydrogen bonding behavior of some thioureas have been investigated and it is found that intramolecular hydrogen bonds between the carbonyl oxygen and a nitrogen atom is common. The complexing capacity of thiourea derivatives has been reported (Schuster et al., 1990). Also, some acyl thioureas have been found to possess pesticidal activities and promote plant growth while others have been shown to have a notable positive effect on the germination of maize seeds and on the chlorophyll contents in seedling leaves (Che et al., 1999). With the simultaneous presence of S, N and O electron donors, the versalitility and behavior of acylthioureas as building blocks in polydentate ligands for metal ions have become a recent topic of interest. Substituted acylthiourea ligands might act as monodentate sulfur donors, bidentate oxygen and nitrogen donors. In continuation of our research program concerned with structural modification of biologically active thiourea derivatives and their transition metal complexes, we aim to incorporate the aliphatic and aromatic moieties in the substituted phenyl nucleus with thiourea functionality to obtain new functions in an attempt to improve the antimicrobial profile of these compounds. In view of the importance of thiourea derivatives, the crystal structure of the title compound, C 18 H 14 N 2 O S , (I), is reported.

Experimental
A solution of benzoyl chloride (0.01 mol) in anhydrous acetone (80 ml) and 3% tetrabutylammonium bromide (TBAB) as a phase-transfer catalyst (PTC) in anhydrous acetone was added dropwise to a suspension of dry ammonium thiocyanate (0.01 mol) in acetone (50 ml) and the reaction mixture was refluxed for 45 min. After cooling to room temperature, a solution of 1-naphthylamine (0.01 mol) in anhydrous acetone (25 ml) was added dropwise and the resulting mixture refluxed for 2.5 h. Hydrochloric acid (0.1 N, 300 ml) was added, and the solution was filtered. The solid product was washed with water and purified by re-crystallization from ethanol.   as those based on F, and R-factors based on ALL data will be even larger..