1-(3,5-Dimethyl-1H-pyrazol-1-yl)-3-phenylisoquinoline

The molecular conformation of the title compound, C20H17N3, is stabilized by an intramolecular C—H⋯N interaction. The crystal structure shows intermolecular C—H⋯π interactions. The dihedral angle between the isoquinoline unit and the phenyl ring is 11.42 (1)° whereas the isoquinoline unit and the pendent dimethyl pryrazole unit form a dihedral angle of 50.1 (4)°. Furthermore, the angle between the mean plane of the phenyl ring and the dimethyl pyrazole unit is 47.3 (6)°.


Comment
Isoquinolines are an integral part of many naturally occurring fused heterocycles and find applications in synthetic and pharmaceutical chemistry (Kametani et al., 1968). 3-substituted isoquinolines are of potent use in medicine, (Chao et al., 1999) and in general, hydrazine derivatives can be used as medicaments (Broadhurst et al., 2001). Choudhury et al. (2002Choudhury et al. ( , 2006 reported crystal structures of substituted isoquinolines while Hathwar et al. (2008) report the crystal structure of an isoquinolinyl diselenide. Similarly, compounds containing the pyrazole motif are being developed in a wide range of therapeutic areas including CNS, metabolic diseases and endocrine functions, and oncology (Elguero et al., 2002). A number of pyrazole-containing compounds have been successfully commercialized, such as the blockbuster drugs Viagra, Celebrex, and Acomplia. In view of the diverse applications of this class of compounds, we report here the crystal structure of isoquinoline pyrazole, namely 1-(2,5-dimethyl-1H-pyrrol-1-yl)-3-phenylisoquinoline.
Although there are no intermolecular C-H···N hydrogen bonds, the molecules are linked by C-H···π interactions.
In the absence of strong hydrogen-bond donors in (I), the crystal packing is controlled by the involvement of weak C-H..pi intermolecular interactions.

Experimental
The 3-phenylisoquinolinehydrazine, and the 1, 3-diketones namely acetylacetone, were taken in ethanol (1:1 ratio) and refluxed under nitrogen overnight. Then the reaction mass was quenched with water, extracted with ethylacetate, washed, dried, concentrated and purified by column chromatography to get titlted compound, (I). Single crystals of the title compound were obtained via recrystalization from a dichloromethane solution

Refinement
All the H atoms in (I) were positioned geometrically and refined using a riding model with C-H bond lenghts of 0.93 Å and 0.97 Å for aromatic and for methylene H atoms respectively and U iso (H) = 1.2U eq (C) for all carbon bound H atoms. Fig. 1. ORTEP diagram of the asymmetric unit of (I) with 50% probability displacement ellipsoids.

Figures
supplementary materials sup-2  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.