4,6-Dimethyl-2-p-tolyl­pyrimidine

Abstract

The mol­ecule of the title compound, C₁₃H₁₄N₂, is located on a crystallographic mirror plane. The aromatic rings make a dihedral angle of 3.4 (2)°. The H atoms of the methyl groups on the benzene ring are disordered over two positions; their site-occupation factors were fixed at 0.5. In the crystal, inter­molecular C—H⋯π contacts form infinite chains perpendicular to the b axis.

Related literature

The title compound was derived from the reaction of p-tolylmercutic chlorides and 4,6-dimethyl-2-iodopyrimidine. For general background to the use of organomercury compounds in cross-coupling reactions, see: Beletskaya et al. (2001 ▶); Braga et al. (2004 ▶). For a related structure, see: Santoni et al. (2008 ▶). For the synthesis, see: Xu et al. (2009a ▶,b ▶).

Experimental

Crystal data

• C₁₃H₁₄N₂

• M _r = 198.26

• Orthorhombic,

• a = 7.2086 (10) Å

• b = 12.4668 (18) Å

• c = 12.4335 (18) Å

• V = 1117.4 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.07 mm⁻¹

• T = 296 K

• 0.35 × 0.25 × 0.22 mm

Data collection

• Bruker SMART APEX CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.976, T _max = 0.985

• 7934 measured reflections

• 1089 independent reflections

• 777 reflections with I > 2σ(I)

• R _int = 0.025

Refinement

• R[F ² > 2σ(F ²)] = 0.042

• wR(F ²) = 0.131

• S = 1.06

• 1089 reflections

• 78 parameters

• H-atom parameters constrained

• Δρ_max = 0.19 e Å⁻³

• Δρ_min = −0.14 e Å⁻³

Data collection: SMART (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); 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: SHELXL97 and PLATON (Spek, 2009 ▶).

Supplementary Material

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
C8—H8⋯Cg1i	0.93	2.79	3.638 (2)	152

Symmetry code: (i) . Cg1 is the centroid of the pyrimidine ring.

supplementary crystallographic information

Comment

The organomercury compounds have a number of notable advantages over other organometallic compounds commonly used in cross-coupling reactions, including higher selectivity of reactions, extra stability and easy availability by a direct mercuration (Beletskaya et al., 2001; Braga et al., 2004). We have recently reported ferrocene-heterocycles were obtained from the coupling reaction(Xu et al., 2009a,b). Here we report the crystal structure of the title compound, derived from the reaction of p-tolylmercutic chlorides and 4,6-dimethyl-2-iodopyrimidine.

Due to the molecular mirror symmetry m of the title compound (Fig.1), and coincidence with the crystallographic mirror plane m (space group Pnma),the atoms C1, C2, C5, C8, H8 are half occupied and the H atoms of the methyl groups in the benzene ring are disordered over two positions; their site-occupation factors were fixed at 0.5. The aromatic rings have very small angles between their planes (dihedral angle is 3.4 (2)°) due to the absence of H—H repulsion (Santoni et al., 2008). Fig.2 shows that in the crystal there exist intermolecular C—H···π interactions (Table 1, Cg1 is the centroid of the pyrimidine ring).

Experimental

The title compound was obtained from the coupling reaction of p-tolylmercutic chlorides and 4,6-dimethyl-2-iodopyrimidine as described in literature (Xu et al., 2009b) and recrystallized from ethanol at room temperature to give the desired crystals suitable for single-crystal X-ray diffraction.

Refinement

H atoms attached to C atoms of the title compound were placed in geometrically idealized positions and treated as riding with C—H distances constrained to 0.93–0.96 Å, and with U_iso(H)=1.2–1.5U_eq(C).

Figures

Fig. 1.

The molecular structure of the title compound with displacement ellipsoids at the 30% probability level, the disordered H atoms are omitted (Symmetry code A: -x + 2, -y, -z).

Fig. 2.

Partial view of the crystal packing showing the formation of the infinite chain of molecules formed by the C—H···π interactions.

Crystal data

C13H14N2	Dx = 1.179 Mg m−3
Mr = 198.26	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnma	Cell parameters from 1634 reflections
a = 7.2086 (10) Å	θ = 2.3–23.3°
b = 12.4668 (18) Å	µ = 0.07 mm−1
c = 12.4335 (18) Å	T = 296 K
V = 1117.4 (3) Å3	Block, colourless
Z = 4	0.35 × 0.25 × 0.22 mm
F(000) = 424

Data collection

Bruker SMART APEX CCD area-detector diffractometer	1089 independent reflections
Radiation source: fine-focus sealed tube	777 reflections with I > 2σ(I)
graphite	Rint = 0.025
phi and ω scans	θmax = 25.5°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→8
Tmin = 0.976, Tmax = 0.985	k = −15→15
7934 measured reflections	l = −15→14

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.131	H-atom parameters constrained
S = 1.06	w = 1/[σ2(Fo2) + (0.0557P)2 + 0.291P] where P = (Fo2 + 2Fc2)/3
1089 reflections	(Δ/σ)max < 0.001
78 parameters	Δρmax = 0.19 e Å−3
0 restraints	Δρmin = −0.14 e Å−3

Special details

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 takeninto account individually in the estimation of e.s.d.'s in distances, anglesand torsion angles; correlations between e.s.d.'s in cell parameters are onlyused 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 andgoodness of fit S are based on F2, conventional R-factors R are basedon F, with F set to zero for negative F2. The threshold expression ofF2 > σ(F2) is used only for calculating R-factors(gt) etc. and isnot relevant to the choice of reflections for refinement. R-factors basedon 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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
C1	0.8988 (4)	0.2500	0.6728 (2)	0.0709 (8)
H1A	0.8781	0.2870	0.7394	0.106*	0.50
H1B	0.9952	0.2856	0.6332	0.106*	0.50
H1C	0.9355	0.1774	0.6874	0.106*	0.50
C2	0.7231 (3)	0.2500	0.60770 (17)	0.0499 (6)
C3	0.6383 (2)	0.34507 (13)	0.57708 (13)	0.0544 (5)
H3	0.6934	0.4100	0.5953	0.065*
C4	0.4741 (2)	0.34546 (12)	0.52012 (13)	0.0522 (5)
H4	0.4201	0.4105	0.5009	0.063*
C5	0.3884 (3)	0.2500	0.49107 (16)	0.0449 (5)
C6	0.2078 (3)	0.2500	0.43367 (17)	0.0468 (5)
C7	−0.0325 (2)	0.34504 (13)	0.36089 (13)	0.0529 (5)
C8	−0.1188 (3)	0.2500	0.33466 (18)	0.0549 (6)
H8	−0.2331	0.2500	0.3000	0.066*
C9	−0.1170 (3)	0.45227 (14)	0.33570 (16)	0.0732 (6)
H9A	−0.0974	0.5001	0.3951	0.110*
H9B	−0.2477	0.4438	0.3235	0.110*
H9C	−0.0598	0.4814	0.2724	0.110*
N1	0.13292 (18)	0.34589 (10)	0.41062 (10)	0.0509 (4)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0703 (17)	0.0703 (18)	0.0720 (17)	0.000	−0.0169 (14)	0.000
C2	0.0541 (14)	0.0531 (13)	0.0425 (11)	0.000	−0.0007 (10)	0.000
C3	0.0600 (11)	0.0446 (9)	0.0584 (10)	−0.0043 (8)	−0.0036 (8)	−0.0048 (7)
C4	0.0588 (10)	0.0390 (9)	0.0589 (10)	0.0022 (7)	−0.0028 (8)	0.0002 (7)
C5	0.0507 (12)	0.0407 (11)	0.0433 (11)	0.000	0.0027 (10)	0.000
C6	0.0545 (13)	0.0430 (12)	0.0428 (11)	0.000	0.0018 (10)	0.000
C7	0.0550 (10)	0.0541 (10)	0.0496 (9)	0.0045 (8)	0.0009 (7)	0.0034 (7)
C8	0.0510 (13)	0.0608 (15)	0.0528 (13)	0.000	−0.0047 (11)	0.000
C9	0.0702 (12)	0.0598 (12)	0.0896 (14)	0.0091 (10)	−0.0128 (10)	0.0094 (10)
N1	0.0546 (8)	0.0449 (8)	0.0532 (8)	0.0031 (6)	−0.0025 (6)	0.0021 (6)

Geometric parameters (Å, °)

C1—C2	1.503 (3)	C5—C6	1.485 (3)
C1—H1A	0.9600	C6—N1i	1.3426 (16)
C1—H1B	0.9600	C6—N1	1.3426 (16)
C1—H1C	0.9600	C7—N1	1.343 (2)
C2—C3i	1.387 (2)	C7—C8	1.378 (2)
C2—C3	1.387 (2)	C7—C9	1.502 (2)
C3—C4	1.380 (2)	C8—C7i	1.378 (2)
C3—H3	0.9300	C8—H8	0.9300
C4—C5	1.3885 (19)	C9—H9A	0.9600
C4—H4	0.9300	C9—H9B	0.9600
C5—C4i	1.3885 (19)	C9—H9C	0.9600
C2—C1—H1A	109.5	C4i—C5—C6	121.00 (11)
C2—C1—H1B	109.5	N1i—C6—N1	125.8 (2)
H1A—C1—H1B	109.5	N1i—C6—C5	117.07 (10)
C2—C1—H1C	109.5	N1—C6—C5	117.07 (10)
H1A—C1—H1C	109.5	N1—C7—C8	121.12 (16)
H1B—C1—H1C	109.5	N1—C7—C9	116.67 (15)
C3i—C2—C3	117.4 (2)	C8—C7—C9	122.20 (16)
C3i—C2—C1	121.28 (11)	C7—C8—C7i	118.7 (2)
C3—C2—C1	121.28 (11)	C7—C8—H8	120.7
C4—C3—C2	121.48 (16)	C7i—C8—H8	120.7
C4—C3—H3	119.3	C7—C9—H9A	109.5
C2—C3—H3	119.3	C7—C9—H9B	109.5
C3—C4—C5	120.81 (16)	H9A—C9—H9B	109.5
C3—C4—H4	119.6	C7—C9—H9C	109.5
C5—C4—H4	119.6	H9A—C9—H9C	109.5
C4—C5—C4i	118.0 (2)	H9B—C9—H9C	109.5
C4—C5—C6	121.00 (11)	C6—N1—C7	116.62 (15)
C3i—C2—C3—C4	1.2 (3)	C4i—C5—C6—N1	178.65 (17)
C1—C2—C3—C4	−178.02 (19)	N1—C7—C8—C7i	0.3 (3)
C2—C3—C4—C5	−0.3 (3)	C9—C7—C8—C7i	−179.77 (14)
C3—C4—C5—C4i	−0.7 (3)	N1i—C6—N1—C7	0.6 (3)
C3—C4—C5—C6	177.47 (16)	C5—C6—N1—C7	−178.53 (15)
C4—C5—C6—N1i	−178.65 (17)	C8—C7—N1—C6	−0.4 (3)
C4i—C5—C6—N1i	−0.6 (3)	C9—C7—N1—C6	179.62 (16)
C4—C5—C6—N1	0.6 (3)

Symmetry codes: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8···Cg1ii	0.93	2.79	3.638 (2)	152

Symmetry codes: (ii) −x−1, y+1/2, −z.