6-Chloro-N 4,N 4-dimethyl­pyrimidine-2,4-diamine

Yuan-Yuan Pang; Kai Yu; Bin Sun; Dian-Shun Guo

doi:10.1107/S1600536812013517

. 2012 Apr 4;68(Pt 5):o1294–o1295. doi: 10.1107/S1600536812013517

6-Chloro-N ⁴,N ⁴-dimethylpyrimidine-2,4-diamine

Yuan-Yuan Pang ^a, Kai Yu ^a, Bin Sun ^a, Dian-Shun Guo ^a,^*

PMCID: PMC3344442 PMID: 22590204

Abstract

The asymmetric unit of the title compound, C₆H₉ClN₄, contains four independent molecules (A, B, C and D). Their main difference is the torsion angles, ranging from 1.6 (5) to 5.9 (5)°, between the methyl group and the pyrimidine plane. A pair of intermolecular N—H⋯N hydrogen bonds link molecules A and C into a twisted dimer with a dihedral angle of 32.9 (1)° between the two pyrimidine rings, creating an R ₂ ²(8) motif. In the packing, each two molecules of B, C and D form centrosymmetric dimers through two intermolecular N—H⋯N hydrogen bonds, locally creating R ₂ ²(8) motifs. The dimers of C and D are alternately bridged by A into an infinite zigzag strip, locally creating two different R ₂ ²(8) motifs with dihedral angles of 32.9 (1) and 63.4 (1)° between the pyrimidine rings. Finally, these strips together with the dimers of B associate into a complicated three-dimensional framework.

Related literature

For background to pyrimidine derivatives, see: Ligthart et al. (2005 ▶); Rabie et al. (2007 ▶); Goswami et al.(2008 ▶); Sherrington & Taskinen (2001 ▶). For similar structures, see: Cetina et al. (2005 ▶); Fun et al. (2006 ▶); Li et al. (2008 ▶); Ebenezer & Muthiah (2010 ▶); Cheng et al. (2011 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₆H₉ClN₄
M _r = 172.62
Triclinic,
a = 7.9438 (19) Å
b = 14.225 (3) Å
c = 14.895 (3) Å
α = 100.114 (3)°
β = 94.421 (4)°
γ = 100.524 (4)°
V = 1618.7 (7) Å³
Z = 8
Mo Kα radiation
μ = 0.41 mm⁻¹
T = 298 K
0.21 × 0.18 × 0.16 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1999 ▶) T _min = 0.919, T _max = 0.937
8239 measured reflections
5619 independent reflections
3769 reflections with I > 2σ(I)
R _int = 0.029

Refinement

R[F ² > 2σ(F ²)] = 0.058
wR(F ²) = 0.136
S = 0.97
5619 reflections
405 parameters
H-atom parameters constrained
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT (Bruker, 1999 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812013517/zq2159sup1.cif

e-68-o1294-sup1.cif^{(26.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812013517/zq2159Isup2.hkl

e-68-o1294-Isup2.hkl^{(275.1KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812013517/zq2159Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N11—H11B⋯N1	0.87	2.48	3.310 (4)	161
N3—H3A⋯N9	0.86	2.41	3.264 (4)	168
N16—H16B⋯N15ⁱ	0.87	2.17	3.038 (4)	174
N11—H11A⋯N10ⁱⁱ	0.87	2.21	3.086 (4)	174
N7—H7B⋯N5ⁱⁱⁱ	0.88	2.19	3.064 (3)	178
N3—H3B⋯N6^iv	0.89	2.35	3.230 (4)	169
N7—H7A⋯N2^iv	0.87	2.33	3.136 (3)	155

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

Financial support from the National Natural Science Foundation of China (grant No. 20572064) and the Natural Science Foundation of Shandong Province (grant No. ZR2010BM022) is gratefully acknowledged.

supplementary crystallographic information

Comment

Functionalized pyrimidines play a major role in molecular recognition and supramolecular chemistry because of their potential ability to form stable hydrogen-bonded chains via their stereochemically associated amino groups and annular N atoms (Sherrington et al., 2001; Ligthart et al., 2005; Rabie et al., 2007; Goswami et al., 2008; Cheng et al., 2011). Lots of substituted 2-aminopyrimidine compounds have been elucidated (Fun et al., 2006; Li et al., 2008; Ebenezer et al., 2010; Cheng et al., 2011). We report here the crystal structure of a related organic compound, 6-chloro-N⁴,N⁴-dimethylpyrimidine-2,4-diamine.

The title compound, C₆H₉ClN₄, contains four crystallographically independent molecules (Fig. 1), A, B, C and D, in the asymmetric unit, among which A and C are connected into a twisted dimer by two intermolecular N3—H3A···N9 and N11—H11B···N1 hydrogen bonds (Table 1), with a dihedral angle of 32.9 (1)° between the two pyrimidine rings. The bond lengths and angles of all molecules are similar except for the torsion angles between the methyl groups and the pyrimidine rings, ranging from 1.6 (5) to 5.9 (5)°.

In the packing of the title compound, each inversion-related two molecules of B, C and D form a centrosymmetric dimer through two intermolecular N—H···N hydrogen bonds (Table 1), locally creating an R₂²(8) motif (Bernstein et al., 1995). For example, in the dimer of D (Fig. 2), hydrogen bonds arise from atoms N7—H7B at (x, y, z) and (-x + 1, -y + 1, -z), which act as hydrogen-bond donors, respectively, to atoms N5 at (-x + 1, -y + 1, -z) and (x, y, z). The dimers of C and D are alternately arranged and bridged by the molecule A, creating an infinite zigzag strip (Cetina et al., 2005) (Fig. 3). In such a strip, the amino group of each molecule acts as a dual donor in N—H···N hydrogen bonds, while the pyrimidine ring serves as a dual acceptor. Interestingly, two different R₂²(8) motifs are formed with dihedral angles of 32.9 (1) and 63.4 (1)° between two adjacent pyrimidine rings. Finally, these strips together with the dimers of B are packed into a complicated three dimensional framework.

Experimental

2-Amino-4,6-dichloropyrimidine (0.082 g, 0.5 mmol) and K₂CO₃ (0.276 g, 2 mmol) were dissolved in DMF (2 ml) and H₂O (2 ml), the mixture was heated at 343 K for 0.5 h and then cooled to room temperature. The resulting mixture was extracted with ethyl acetate. The organic layer was separated and washed with brine, then dried over anhydrous MgSO₄. Removal of the solvent under reduced pressure gave the title compound as a yellow solid (yield 85%). Single crystals suitable for X-ray diffraction analysis were obtained by liquid–liquid diffusion from hexane and CH₂Cl₂ at 298 K.