organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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2,6-Di­chloro-7-iso­propyl-7H-purine

aDepartment of Chemistry, Faculty of Technology, Tomas Bata University in Zlin, Nám. T. G. Masaryka 275, Zlín, 762 72, Czech Republic, and bDepartment of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, Brno-Bohunice, 625 00, Czech Republic
*Correspondence e-mail: rvicha@ft.utb.cz

(Received 16 April 2012; accepted 26 April 2012; online 2 May 2012)

In the title mol­ecule, C8H8Cl2N4, the essentially planar imidazole and pyrimidine rings [maximum deviations of 0.0030 (15) and 0.0111 (15) Å, respectively] make a dihedral angle of 1.32 (8)°. In the crystal, the fused-ring systems are stacked approximately parallel to the bc plane, with a centroid–centroid distance between inversion-related pyrimidine rings of 3.5189 (9) Å.

Related literature

For the synthesis, see: Oumata et al. (2008[Oumata, M., Bettayeb, K., Ferandin, Y., Demange, L., Lopez-Giral, A., Goddard, M.-L., Myrianthopoulos, V., Mikros, E., Flajolet, M., Greengard, P., Meijer, L. & Galons, H. (2008). J. Med. Chem. 51, 5229-5242.]). For biological activity of some purine derivatives, see: Legraverend & Grierson (2006[Legraverend, M. & Grierson, D. S. (2006). Bioorg. Med. Chem. 14, 3987-4006.]). For the selective synthesis of N7-substituted purines, see: Kotek et al. (2010[Kotek, V., Chudíková, N., Tobrman, T. & Dvořák, D. (2010). Org. Lett. 12, 5724-5727.]). For related structures, see: Rouchal et al. (2009a[Rouchal, M., Nečas, M., Carvalho, F. P. de & Vícha, R. (2009a). Acta Cryst. E65, o298-o299.],b[Rouchal, M., Nečas, M. & Vícha, R. (2009b). Acta Cryst. E65, o1268.], 2010[Rouchal, M., Nečas, M. & Vícha, R. (2010). Acta Cryst. E66, o1016.]).

[Scheme 1]

Experimental

Crystal data
  • C8H8Cl2N4

  • Mr = 231.08

  • Triclinic, [P \overline 1]

  • a = 7.0146 (5) Å

  • b = 8.2862 (6) Å

  • c = 8.9686 (7) Å

  • α = 70.499 (7)°

  • β = 83.820 (6)°

  • γ = 74.204 (6)°

  • V = 472.75 (7) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.65 mm−1

  • T = 120 K

  • 0.40 × 0.40 × 0.20 mm

Data collection
  • Oxford Diffraction Xcalibur Sapphire2 diffractometer

  • Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis RED and CrysAlis CCD. Oxford Diffraction Ltd, Yarnton, England.]) Tmin = 0.933, Tmax = 1.000

  • 2825 measured reflections

  • 1656 independent reflections

  • 1419 reflections with I > 2σ(I)

  • Rint = 0.011

Refinement
  • R[F2 > 2σ(F2)] = 0.023

  • wR(F2) = 0.061

  • S = 1.05

  • 1656 reflections

  • 129 parameters

  • H-atom parameters constrained

  • Δρmax = 0.26 e Å−3

  • Δρmin = −0.24 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis RED and CrysAlis CCD. Oxford Diffraction Ltd, Yarnton, England.]); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2009[Oxford Diffraction (2009). CrysAlis RED and CrysAlis CCD. Oxford Diffraction Ltd, Yarnton, England.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Purines represent a class of compounds with wide range of biological activities. The most of biologically active purines are di-, tri- or tetrasubstituted, usually on the C(2), C(6), C(8) and/or N(9) centers. Moreover, interesting biological properties were also described for some N7-substituted purines (Legraverend & Grierson, 2006). Owing to the relatively small portions of N7 isomer originating within the direct alkylation of purine bases, the selective synthesis of N7-substituted purines was recently described (Kotek et al., 2010). The title molecule was isolated as a side product forming during the synthesis of novel 2,6,9-trisubstituted purine series.

The asymmetric unit of the title compound consists of a single purine molecule (Fig. 1). Both imidazole and pyrimidine rings are essentially planar with maximum deviations from the best plane being 0.0030 (15) Å for C4 (imidazole ring) and 0.0111 (15) Å for C3 (pyrimidine ring). The dihedral angle between the two rings is 1.32 (8)°. In the crystal packing (Fig .2), molecules are stacked parallel to the bc-plane. The distance between purine ring atoms (-x, 1 - y, -z) and best plane of adjacent purine ring (x, y, z) varies from -3.4111 (15) Å for N4 to -3.3728 (15) Å for C3. We have already published the structures of some related compounds (Rouchal et al., 2009a,b; Rouchal et al., 2010).

Related literature top

For the synthesis, see: Oumata et al. (2008). For biological activity of some purine derivatives, see: Legraverend & Grierson (2006). For the selective synthesis of N7-substituted purines, see: Kotek et al. (2010). For related structures, see: Rouchal et al. (2009a,b, 2010).

Experimental top

The title compound was prepared following modified literature procedure (Oumata et al., 2008). To a well stirred solution of 2,6-dichloro-9H-purine (4.5 g, 23.8 mmol) in DMSO (50 cm3), potassium carbonate (9.9 g, 71.4 mmol) and 2-iodopropane (11.9 cm3, 119.0 mmol) were added. The reaction mixture was stirred at 288–291K for 8 h. After that, the mixture was diluted with water (50 cm3) and extracted with ether (7 × 15 cm3). Collected organic layers were washed with brine (2 × 10 cm3), dried over sodium sulfate and evaporated in vacuo. Both N7 and N9 isomers were separated from the crude material using column chromatography (silicagel; petroleum ether/ethyl acetate, 1/1, v/v). 2,6-Dichloro-7-isopropyl-7H-purine was obtained as a pale yellow crystalline powder (mp 425–427 K) in minor fraction. The crystal used for data collection was grown by spontaneous evaporation from deuterochloroform at room temperature.

Refinement top

All carbon bound H atoms were placed at calculated positions and were refined as riding with their Uiso set to either 1.2Ueq or 1.5Ueq (methyl) of the respective carrier atoms; in addition, the methyl H atoms were allowed to rotate about the C—C bond.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2009); cell refinement: CrysAlis CCD (Oxford Diffraction, 2009); data reduction: CrysAlis RED (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure with 50% probability ellipsoids. H-atoms are shown as small spheres at arbitrary radii.
[Figure 2] Fig. 2. Molecules of title compound stacked along the a-axis. H-atoms have been omitted for clarity.
2,6-Dichloro-7-isopropyl-7H-purine top
Crystal data top
C8H8Cl2N4Z = 2
Mr = 231.08F(000) = 236
Triclinic, P1Dx = 1.623 Mg m3
Hall symbol: -P 1Melting point: 426 K
a = 7.0146 (5) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.2862 (6) ÅCell parameters from 2034 reflections
c = 8.9686 (7) Åθ = 3.0–27.7°
α = 70.499 (7)°µ = 0.65 mm1
β = 83.820 (6)°T = 120 K
γ = 74.204 (6)°Block, colourless
V = 472.75 (7) Å30.40 × 0.40 × 0.20 mm
Data collection top
Oxford Diffraction Xcalibur Sapphire2
diffractometer
1656 independent reflections
Radiation source: Enhance (Mo) X-ray Source1419 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.011
Detector resolution: 8.4353 pixels mm-1θmax = 25.0°, θmin = 3.5°
ω scanh = 88
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2009)
k = 99
Tmin = 0.933, Tmax = 1.000l = 1010
2825 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.023Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.061H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0323P)2 + 0.0416P]
where P = (Fo2 + 2Fc2)/3
1656 reflections(Δ/σ)max < 0.001
129 parametersΔρmax = 0.26 e Å3
0 restraintsΔρmin = 0.24 e Å3
Crystal data top
C8H8Cl2N4γ = 74.204 (6)°
Mr = 231.08V = 472.75 (7) Å3
Triclinic, P1Z = 2
a = 7.0146 (5) ÅMo Kα radiation
b = 8.2862 (6) ŵ = 0.65 mm1
c = 8.9686 (7) ÅT = 120 K
α = 70.499 (7)°0.40 × 0.40 × 0.20 mm
β = 83.820 (6)°
Data collection top
Oxford Diffraction Xcalibur Sapphire2
diffractometer
1656 independent reflections
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction, 2009)
1419 reflections with I > 2σ(I)
Tmin = 0.933, Tmax = 1.000Rint = 0.011
2825 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0230 restraints
wR(F2) = 0.061H-atom parameters constrained
S = 1.05Δρmax = 0.26 e Å3
1656 reflectionsΔρmin = 0.24 e Å3
129 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 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 (Å2) top
xyzUiso*/Ueq
Cl10.22677 (6)0.42378 (6)0.21906 (5)0.02126 (13)
Cl20.31193 (6)0.39565 (5)0.35468 (5)0.02020 (13)
N10.2261 (2)0.71202 (18)0.16073 (15)0.0172 (3)
N20.26395 (19)0.44137 (17)0.05831 (15)0.0160 (3)
N30.27132 (19)0.83054 (17)0.17303 (15)0.0150 (3)
N40.2361 (2)0.96725 (18)0.09060 (15)0.0175 (3)
C10.2390 (2)0.5421 (2)0.09346 (19)0.0160 (4)
C20.2758 (2)0.5246 (2)0.15927 (18)0.0153 (4)
C30.2616 (2)0.7041 (2)0.10815 (18)0.0139 (3)
C40.2541 (2)0.9822 (2)0.04869 (19)0.0177 (4)
H40.25491.09140.06130.021*
C50.2397 (2)0.7924 (2)0.05616 (18)0.0153 (4)
C60.2741 (2)0.8107 (2)0.34377 (18)0.0165 (4)
H60.36830.69520.39720.020*
C70.3474 (3)0.9569 (2)0.3651 (2)0.0245 (4)
H7A0.47650.95890.31150.037*
H7B0.36080.93580.47820.037*
H7C0.25251.07080.31950.037*
C80.0694 (2)0.8061 (2)0.41748 (19)0.0203 (4)
H8A0.02530.91860.36700.030*
H8B0.07330.78790.53100.030*
H8C0.02820.70900.40200.030*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0217 (2)0.0247 (2)0.0217 (2)0.00501 (18)0.00236 (17)0.01289 (18)
Cl20.0284 (3)0.0158 (2)0.0155 (2)0.00685 (18)0.00177 (17)0.00235 (17)
N10.0152 (7)0.0196 (8)0.0164 (7)0.0033 (6)0.0005 (6)0.0062 (6)
N20.0136 (7)0.0170 (8)0.0182 (7)0.0040 (6)0.0006 (6)0.0064 (6)
N30.0158 (7)0.0140 (7)0.0155 (7)0.0047 (6)0.0004 (6)0.0041 (6)
N40.0188 (8)0.0152 (8)0.0177 (7)0.0045 (6)0.0003 (6)0.0038 (6)
C10.0109 (8)0.0211 (9)0.0188 (8)0.0034 (7)0.0003 (7)0.0105 (7)
C20.0109 (8)0.0182 (9)0.0152 (8)0.0035 (7)0.0004 (6)0.0036 (7)
C30.0094 (8)0.0166 (9)0.0162 (8)0.0030 (7)0.0005 (6)0.0062 (7)
C40.0161 (9)0.0137 (8)0.0220 (9)0.0045 (7)0.0003 (7)0.0038 (7)
C50.0103 (8)0.0184 (9)0.0162 (8)0.0030 (7)0.0005 (6)0.0050 (7)
C60.0185 (9)0.0166 (9)0.0145 (8)0.0036 (7)0.0017 (7)0.0053 (7)
C70.0301 (11)0.0255 (10)0.0230 (9)0.0119 (8)0.0007 (8)0.0104 (8)
C80.0227 (10)0.0233 (10)0.0159 (8)0.0066 (8)0.0016 (7)0.0077 (7)
Geometric parameters (Å, º) top
Cl1—C11.7437 (16)C3—C51.414 (2)
Cl2—C21.7249 (16)C4—H40.9500
N1—C11.315 (2)C6—C71.511 (2)
N1—C51.343 (2)C6—C81.519 (2)
N2—C21.3289 (19)C6—H61.0000
N2—C11.339 (2)C7—H7A0.9800
N3—C41.360 (2)C7—H7B0.9800
N3—C31.3770 (19)C7—H7C0.9800
N3—C61.486 (2)C8—H8A0.9800
N4—C41.318 (2)C8—H8B0.9800
N4—C51.371 (2)C8—H8C0.9800
C2—C31.381 (2)
C1—N1—C5112.46 (14)N4—C5—C3110.38 (14)
C2—N2—C1115.85 (14)N3—C6—C7110.35 (13)
C4—N3—C3105.08 (13)N3—C6—C8109.77 (12)
C4—N3—C6127.26 (14)C7—C6—C8112.12 (14)
C3—N3—C6127.25 (13)N3—C6—H6108.2
C4—N4—C5103.55 (13)C7—C6—H6108.2
N1—C1—N2130.38 (15)C8—C6—H6108.2
N1—C1—Cl1116.32 (12)C6—C7—H7A109.5
N2—C1—Cl1113.29 (12)C6—C7—H7B109.5
N2—C2—C3121.08 (14)H7A—C7—H7B109.5
N2—C2—Cl2116.30 (12)C6—C7—H7C109.5
C3—C2—Cl2122.62 (13)H7A—C7—H7C109.5
N3—C3—C2137.57 (15)H7B—C7—H7C109.5
N3—C3—C5105.65 (13)C6—C8—H8A109.5
C2—C3—C5116.70 (15)C6—C8—H8B109.5
N4—C4—N3115.34 (15)H8A—C8—H8B109.5
N4—C4—H4122.3C6—C8—H8C109.5
N3—C4—H4122.3H8A—C8—H8C109.5
N1—C5—N4126.13 (14)H8B—C8—H8C109.5
N1—C5—C3123.49 (15)

Experimental details

Crystal data
Chemical formulaC8H8Cl2N4
Mr231.08
Crystal system, space groupTriclinic, P1
Temperature (K)120
a, b, c (Å)7.0146 (5), 8.2862 (6), 8.9686 (7)
α, β, γ (°)70.499 (7), 83.820 (6), 74.204 (6)
V3)472.75 (7)
Z2
Radiation typeMo Kα
µ (mm1)0.65
Crystal size (mm)0.40 × 0.40 × 0.20
Data collection
DiffractometerOxford Diffraction Xcalibur Sapphire2
diffractometer
Absorption correctionMulti-scan
(CrysAlis RED; Oxford Diffraction, 2009)
Tmin, Tmax0.933, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
2825, 1656, 1419
Rint0.011
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.023, 0.061, 1.05
No. of reflections1656
No. of parameters129
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.26, 0.24

Computer programs: CrysAlis CCD (Oxford Diffraction, 2009), CrysAlis RED (Oxford Diffraction, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2008).

 

Acknowledgements

The financial support of this work by the Inter­nal Founding Agency of Tomas Bata University in Zlin (project No. IGA/FT/2012/016) is gratefully acknowledged.

References

First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationKotek, V., Chudíková, N., Tobrman, T. & Dvořák, D. (2010). Org. Lett. 12, 5724–5727.  Web of Science CrossRef CAS PubMed Google Scholar
First citationLegraverend, M. & Grierson, D. S. (2006). Bioorg. Med. Chem. 14, 3987–4006.  Web of Science CrossRef PubMed CAS Google Scholar
First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationOumata, M., Bettayeb, K., Ferandin, Y., Demange, L., Lopez-Giral, A., Goddard, M.-L., Myrianthopoulos, V., Mikros, E., Flajolet, M., Greengard, P., Meijer, L. & Galons, H. (2008). J. Med. Chem. 51, 5229–5242.  Web of Science CrossRef PubMed CAS Google Scholar
First citationOxford Diffraction (2009). CrysAlis RED and CrysAlis CCD. Oxford Diffraction Ltd, Yarnton, England.  Google Scholar
First citationRouchal, M., Nečas, M., Carvalho, F. P. de & Vícha, R. (2009a). Acta Cryst. E65, o298–o299.  Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
First citationRouchal, M., Nečas, M. & Vícha, R. (2009b). Acta Cryst. E65, o1268.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationRouchal, M., Nečas, M. & Vícha, R. (2010). Acta Cryst. E66, o1016.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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