5-Anilino-3-benzylsulfanyl-6-(3-chloroanilino)-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one

In the title compound, C30H23ClN6OS, the benzyl, the 3-chloroanilino, the phenyl and the anilino groups form dihedral angles of 85.95 (6), 29.63 (7), 28.55 (1) and 87.48 (6)°, respectively, with the pyrazolo[3,4-d]pyrimidine unit [maximum deviation = 0.052 (2) Å]. An intramolecular N—H⋯N hydrogen bond occurs. The crystal structure features N—H⋯O hydrogen bonds.

We gratefully acknowledge the service provided by the X-ray facility at the Department of Chemistry and Chemical Engineering, Hengyang Normal University. Financial support of this work by the National Science Foundation (No. 11175080) and by the Natural Science Fund of Hunan Province (No. 10 J J6025) is gratefully acknowledged.
The molecule and packing diagrams of the title compound were shown in Figure 1 and 2, respectively. As shown in Fig.1, the N1=C1 and N3=C4 bonds are 1.318 (3) and 1.304 (3) Å, respectively, slightly shorter than the normal C=N bond (1.329 and 1.336 Å; Allen et al., 1987) but close to 1.314 (3) and 1.302 (3) Å in our previous report (Wang et al., 2004), and the C2=C3 distance is 1.388 (3) Å, longer than the typical C=C(1.384 Å; Allen et al., 1987). In the molecule, the N-C bonds are remarkably shorter than the normal N-C single bond(1.469 Å) and longer than the C=N double bond.
The packing was stabilized by the intermolecular N-H···O hydrogen bond.

Experimental
To a solution of iminophosphorane (2 mmol) in dry dichloromethane (20 ml) aryl isocyanate(2 mmol) was added under nitrogen atmosphere at room temperature. After the reaction mixture was stirred for 1.5 h, 0.231 g (2.0 mmol) m-chlorophenyl isocyanate was added, and the resulting mixture was stirred for an additional 30 min. Then the solvent was removed under reduced pressure, and 25 ml anhydrous ethanol and 1.5 ml of sodium ethoxide (3 mol/L) in ethanol were added to the mixture. After 3 h of stirring at room temperature, the solution was concentrated under reduced pressure and successively cooled. The crude product was collected by filtration. After recrystallization from DMF/petroleum ether or column chromatography on silica gel, white crystals were obtained.

Refinement
H atoms were included in their idealized positions, with C-H = 0.96 Å, and refined using a riding model with U iso (H) = 1.2 U eq (C) for other H atoms.

Figure 2
Hydrogen bonding pattern found in the title compound   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.