2-Chloro-9-isopropyl-N,N-dimethyl-9H-purin-6-amine

In the title compound, C10H14ClN5, the imidazole and pyrimidine rings are essentially planar [maximum deviation = 0.0013 (14) and 0.0207 (13) Å, respectively]. In the crystal, the molecules are linked by weak C—H⋯N interactions into chains parallel to the c axis and the crystal packing is stabilized by additional weak C—H⋯N and C—H⋯Cl interactions.

In the title compound, C 10 H 14 ClN 5 , the imidazole and pyrimidine rings are essentially planar [maximum deviation = 0.0013 (14) and 0.0207 (13) Å , respectively]. In the crystal, the molecules are linked by weak C-HÁ Á ÁN interactions into chains parallel to the c axis and the crystal packing is stabilized by additional weak C-HÁ Á ÁN and C-HÁ Á ÁCl interactions.
The financial support of this work by the Czech Ministry of Education, project No. MSM 7088352101 is gratefully acknowledged.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: PK2238).

Comment
The heterocyclic system, imidazo [4,5-d]pyrimidine, commonly known as purine, was first named by Emil Fisher at the turn of the 19 th century. A large number of variously substituted purines exhibit a wide range of biological activities (Legraverend & Grierson, 2006). They act as interferon inducers, adenosine receptor ligands, inhibitors of microtubule assembly, protein kinases, sulfotransferases and phosphodiesterases. The title molecule was prepared as a part of our research into the synthesis of novel trisubstituted purines.

Experimental
The title compound was prepared according to a slightly modified literature procedure (Fiorini & Abel, 1998). 2,6-Dichloro-9-(propan-2-yl)-9H-purine (0.87 mmol, 196 mg) and methylamine hydrochloride (0.91 mmol, 61.5 mg) were dissolved in a mixture of DMF (2.5 ml) and N-ethyl-N-isopropylpropan-2-amine (1.74 mmol, 225 mg). The resulting solution was stirred at 90 °C for 2 hours. Subsequently, the mixture was diluted with water and extracted with diethyl ether. Combined organic layers were washed twice with brine and dried over Na 2 SO 4 . Crude product consisting of two compounds with relative abundances of 43% and 57% according to GC were obtained after evaporation of the solvent in vacuum. The products were identified as N-methyl and N,N-dimethyl derivatives. Column chromatography (silica gel; petroleum ether/ethyl acetate, v/v, 1/1) yielded the latter as a colourless crystalline powder (105 mg, 54%, mp 418-422 K). The crystal used for data collection was grown by spontaneous evaporation from deuterochloroform at room temperature.
supplementary materials sup-2 Figures   Fig. 1. An ellipsoid plot (50% probability) of the asymmetric unit. Hydrogen atoms are represented as arbitrary spheres.
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq