6-Isopropyl-5-methoxy-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one

In the title compound, C14H15N5O2, the whole molecule apart from the terminal C atoms of the isopropyl group is located on a crystallographic mirror plane. An intramolecular C—H⋯N hydrogen-bonding interaction may stabilize the molecular conformation. The crystal packing features weak slipped π–π interactions between the pyrimidine and the phenyl rings of symmetry-related molecules [centroid–centroid distance = 3.746 (1)Å, slippage of 1.574 Å].

In the title compound, C 14 H 15 N 5 O 2 , the whole molecule apart from the terminal C atoms of the isopropyl group is located on a crystallographic mirror plane. An intramolecular C-HÁ Á ÁN hydrogen-bonding interaction may stabilize the molecular conformation. The crystal packing features weak slippedinteractions between the pyrimidine and the phenyl rings of symmetry-related molecules [centroid-centroid distance = 3.746 (1)Å , slippage of 1.574 Å ].
In recent years, Zhao's group succeeded in synthesizing the derivatives of 8-azaguanine via aza-Wittig reaction of betaethoxycarbonyl iminophosphorane with aromatic isocyanates (Zhao, Xie et al., 2005). As a continuation of the quest for new biologically active derivatives of 8-azaguanine, the title compound, (I), was obtained from beta-ethoxycarbonyl iminophosphorane with aliphatic isocyanate, and structurally characterized.
In the title compound, C 14 H 15 N 5 O 2 , the whole molecule but the terminal C atoms of the isopropyl group is located in a mirror plane and is then perfectly planar (Fig. 1). The bond lengths and angles in the triazolopyrimidinone moiety are in good agreement with those observed for closely related structures (Zhao, Hu et al., 2005;Zhao, Wang & Ding, 2005). the triazolopyrimidine ring system is perfectly coplanar (Chen & Shi, 2006;Ferguson et al., 1998;Li et al., 2004;Maldonado et al., 2006;Wang et al., 2006;Xiao & Shi, 2007;Zeng et al., 2009).
The molecules are packed along the b axis with weak slippest π-π interaction between the pyrimidin and the phenyl rings of symmetry related molecules (Centroid to centroid distance= 3.746 (1)Å, interplanar distance= 3.399 Å with a slippage of 1.574 Å).

Experimental
To the solution of carbodiimide prepared according to Zeng et al. (2006) in a mixed solvent (CH 2 Cl 2 /MeOH,1:4 v/v, 15 ml) was added a fresh prepared solution of Na/MeOH (0.1 g/2 ml). After stirring the reaction mixture for 6 h, the solvent was removed under reduced pressure and the residue was recrystallized from EtOH to give the title compound (I) in 89% yield (m.p. 471 K). Elemental analysis: calculated for C 14 H 15 N 5 O 2 : C, 58.94; H, 5.30; N, 24.55%. Found: C, 57.62; H, 5.72; N, 24.01%. Crystals suitable for X-ray diffraction study were obtained by recrystallization from hexane and dichloromethane (1:3 v/v) at room temperature.

Refinement
All H atoms attached to C atoms and N atom were fixed geometrically and treated as riding with C-H = 0.98 Å (methine), 0.96 Å (methyl) or 0.93 Å (aromatic) with U iso (H) = 1.2U eq (C) or U iso (H) = 1.5U eq (C methyl ).

Special details
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 , convention-