1-(2-Furoyl)-3-(2-methoxy-4-nitrophenyl)thiourea

The asymmetric unit of the title compound, C13H11N3O5S, contains two independent molecules, which are linked by a pair of intermolecular N—H⋯S hydrogen bonds, forming an R 2 2(8) ring motif. The central thiourea core forms dihedral angles of 3.02 (12) and 14.00 (10)° with the essentially planar furoyl groups [maximum deviations = 0.030 (2) and 0.057 (2) Å] in the two molecules and dihedral angles of 2.43 (13) and 8.03 (12)° with the benzene rings. The dihedral angles between the furoyl and benzene rings in the two molecules are 3.97 (10) and 5.98 (9)°. The trans–cis geometry of the thiourea group is stabilized by three intramolecular N—H⋯O hydrogen bonds involving carbonyl and methoxy O atoms with the H atom of the cis-thioamide group and between furan O atom and the other thioamide H atom. There is also a weak intramolecular C—H⋯S interaction in each molecule.

The asymmetric unit of the title compound, C 13 H 11 N 3 O 5 S, contains two independent molecules, which are linked by a pair of intermolecular N-HÁ Á ÁS hydrogen bonds, forming an R 2 2 (8) ring motif. The central thiourea core forms dihedral angles of 3.02 (12) and 14.00 (10) with the essentially planar furoyl groups [maximum deviations = 0.030 (2) and 0.057 (2) Å ] in the two molecules and dihedral angles of 2.43 (13) and 8.03 (12) with the benzene rings. The dihedral angles between the furoyl and benzene rings in the two molecules are 3.97 (10) and 5.98 (9) . The trans-cis geometry of the thiourea group is stabilized by three intramolecular N-HÁ Á ÁO hydrogen bonds involving carbonyl and methoxy O atoms with the H atom of the cis-thioamide group and between furan O atom and the other thioamide H atom. There is also a weak intramolecular C-HÁ Á ÁS interaction in each molecule.

Comment
There is a growing interest in the synthesis of new substituted thiourea derivatives owing to their diverse applicability in the pharmaceutical industry, material science and analytical chemistry. The hydrogen-bonding ability of the thiourea moiety has extensively been used in construction of anion receptors (Doyle & Jacobsen, 2007;Gale et al., 2008;Svetlana 2007). Further, aroyl thioureas have been successfully used in environmental control, as ionophores in ion-selective electrodes (Wilson et al.,2010;Pérez et al., 2008). Recently, these compounds have been employed successfully as catalysts in the palladium-catalyzed Suzuki and Heck reactions Dai et al., 2004). In view of the above and in continuation of our work on thiourea derivatives (Singh et al., 2012a,b,c), the crystal structure of 1-(2furoyl)-3-(2-methoxy-4-nitrophenyl)thiourea has been determined (Fig.1).

Experimental
A solution of 2-furoyl chloride (0.01 mol) in anhydrous acetone (80 ml) was added drop wise to a suspension of ammonium thiocyanate (0.01 mol) in anhydrous acetone (50 ml) and the reaction mixture was heated to reflux for 50 minutes. After cooling to room temperature, a solution of 2-methoxy-4-nitroaniline (0.01 mol) in dry acetone (25 ml) was added slowly and the resulting mixture refluxed for 2 h. The reaction mixture was poured into five times its volume of cold water, upon which the thiourea precipitated. The resulting solid product was crystallized from dimethyl sulphoxide yielding light yellow X-ray quality single crystals. Yield: 82%; M.P.: 451-453 K. Anal. Calc. for C 13 H 11 N 3 O 5 S (%): C,

Refinement
All H atoms were placed in calculated positions and refined using a riding-model approximation with C-H = 0.95-0.98 Å, N-H = 0.88 Å and U iso (H) = 1.2 U eq (C,N) or 1.5 U eq (C methyl ).

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.