Ethyl 4-(3-ethyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-4-yl)benzoate

In the title compound, C13H15N3O3, the dihedral angle between the two aromatic ring is 51.06 (1)°. In the crystal, molecules are connected by pairs of N—H⋯O hydrogen bonds into centrosymmetric dimers.

In the title compound, C 13 H 15 N 3 O 3 , the dihedral angle between the two aromatic ring is 51.06 (1) . In the crystal, molecules are connected by pairs of N-HÁ Á ÁO hydrogen bonds into centrosymmetric dimers.

Crystal data
Furthermore, It was reported that compounds having triazole moieties such as Vorozole, Anastrozole and Letrozole appear to be very effective aromatase inhibitors very useful for preventing breast cancer.

Experimental
Ethyl 2-(1-ethoxypropylidene)hydrazinecarboxylate (10 mmol) and ethyl 4-amino benzoate (10 mmol) was mixed without solvent and heated at 433-443°K for 2 h. The formed solid products were separated by filtration, purified by crystallization twice from ethanol, washed with Et 2 O ether and dried in a vacuum. m p: 446°K.

Refinement
The H atoms of the phenyl ring were positioned geometrically and refined using a riding model with C-H = 0.93 Å and U(H)=1.2U eq (C). The remaining H atoms were freely refined. Fig. 1. A view of the title compound with the atom-numbering scheme and 50% probability displacement ellipsoids.

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 , 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.