Ethyl 4-(3-chlorophenyl)-3,6-dihydroxy-6-methyl-2-(2-pyridyl)-4,5,6,7-tetrahydroindazole-5-carboxylate

In the title compound, C22H22ClN3O4, the cyclohexane ring adopts a twisted half-chair conformation. The molecule is stabilized by an intramolecular O—H⋯N interaction, generating an S(6) motif. The crystal packing is stabilized by intermolecular O—H⋯N and C—H⋯O interactions.

In the title compound, C 22 H 22 ClN 3 O 4 , the cyclohexane ring adopts a twisted half-chair conformation. The molecule is stabilized by an intramolecular O-HÁ Á ÁN interaction, generating an S(6) motif. The crystal packing is stabilized by intermolecular O-HÁ Á ÁN and C-HÁ Á ÁO interactions.

Comment
In azole family, tetrahydroindazoles (cycloalkane derivatives of pyrazoles) are having much importance for their effective biological potencies (Connolly et al., 1997). Our current research work is focused on the stereospecific synthesis of 1(H) and various N-substituted tetrahydroindazoles by taking cyclic β keto esters as an effective synthons, and exploring their stereochemistry. Recently, we have described complete structural elucidation and conformation of a series of N(2)-pyridyl tetrahydroindazoles (Amirthaganesan et al., 2008). One and two dimensional NMR investigations strongly proved that all the compounds obtained as a single isomer where cyclohexane ring adopts slightly distorted chair conformation and pyridyl moiety favored at N(2) position in the azole ring. We report here the X-ray crystal structure of the title compound.
The sum of the bond angles at N2 (359.9 (3)°) indicates the sp 2 hybridization. Atoms O4 and Cl1 lie in the plane of the rings to which they are attached with the deviation of 0.002 (2) and -0.004 (1) Å, respectively. The pyridine (or pyridyl) ring, attached at N(2) position of the pyrazole ring, is parallel to the pyrazole ring with the dihedral angle of 8.0 (1)°.
The molecule is stabilized by strong O-H···N intramolecular interaction, wherein, atom O4 acts as donor to N3 generating S(6) motif. The crystal packing is stabilized by O-H···N and C-H···O intermolecular interactions. Atoms C11 and C16 act as donors to O3 and O4, respectively, each generating chain of C(8), which in turn generates R 4 4 (28) graph set along ab plane. Atom O3 acts as donor to N1 at (-x,-y,-z+1) generating a centrosymmetric dimer of R 2 2 (12) graph set.

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.