3,5-Dichloro-6-methyl­pyridin-2-amine

Fun, H.-K.; Kia, R.; Maity, A.C.; Maity, S.; Goswami, S.

doi:10.1107/S1600536808041366

organic compounds

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ISSN: 2056-9890

Volume 65| Part 1| January 2009| Page o97

doi:10.1107/S1600536808041366

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3,5-Dichloro-6-methylpyridin-2-amine

Hoong-Kun Fun,^a ^* Reza Kia,^a Annada C. Maity,^b Sibaprasad Maity ^b and Shyamaprosad Goswami ^b

^aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^bDepartment of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711 103, India
^*Correspondence e-mail: hkfun@usm.my

(Received 5 December 2008; accepted 7 December 2008; online 13 December 2008)

In the title compound, C₆H₆Cl₂N₂, intramolecular N–H⋯Cl and C—H⋯Cl contacts generate five-membered rings, producing S(5) ring motifs. Pairs of intermolecular N—H⋯N hydrogen bonds link neighbouring molecules into dimers with R²₂(8) ring motifs. In the crystal structure, these dimers are connected by N—H⋯Cl interactions and are packed into columns.

Related literature

For details of hydrogen-bond motifs, see: Bernstein et al. (1995 ). For related literature and applications see, for example: Goswami & Maity (2007 ); Taylor et al. (1989 ); Taylor & Ray (1988 ); Beer et al. (1993 ); Goswami et al. (2000 , 2005 ); Fun et al. (2008 ).

Experimental

Crystal data

C₆H₆Cl₂N₂
M_r = 177.03
Monoclinic, P 2₁ /n
a = 12.7670 (3) Å
b = 3.8037 (1) Å
c = 15.4129 (3) Å
β = 104.990 (1)°
V = 723.01 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.81 mm⁻¹
T = 100.0 (1) K
0.45 × 0.31 × 0.28 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.711, T_max = 0.803
26531 measured reflections
3795 independent reflections
3485 reflections with I > 2˘I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.024
wR(F²) = 0.071
S = 1.11
3795 reflections
115 parameters
All H-atom parameters refined
Δρ_max = 0.61 e Å⁻³
Δρ_min = −0.42 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2N1⋯N1ⁱ	0.869 (15)	2.168 (15)	3.0320 (9)	172.8 (13)
N2—H1N1⋯Cl2	0.828 (14)	2.603 (14)	3.0156 (7)	112.3 (12)
C6—H6A⋯Cl1	1.02 (2)	2.67 (2)	3.1318 (9)	108.0 (14)
N2—H1N1⋯Cl2ⁱⁱ	0.828 (14)	2.900 (14)	3.6758 (7)	156.9 (13)
Symmetry code: (i) -x+1, -y+1, -z.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808041366/tk2343sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808041366/tk2343Isup2.hkl

checkCIF report

Comment top

The halogen substituted π-depleted heteroaromatics (e.g. pterin, quinoxaline, naphthyridine, or pyridine derivatives) are important intermediates in modern organic chemistry (Goswami & Maity 2007; Taylor et al. 1989; Taylor & Ray 1988; Beer et al. 1993), e.g. they are used as precursors for pharmacologically active compounds. These are also versatile compounds in manifold synthesis of artificial receptors for molecular recognition (Goswami et al. 2000, 2005; Fun et al. 2008).

In the title compound (I), Fig. 1, intramolecular N–H···Cl and C—H···Cl contacts generate five-membered rings, producing S(5) ring motifs (Bernstein et al., 1995). Pairs of intermolecular N—H···N hydrogen bonds link molecules into dimers with a R²₂(8) ring motif (Table 1). In the crystal structure, these dimers are connected by N—H···Cl interactions and are packed into columns along the b axis, Fig. 2.

Related literature top

For details of hydrogen-bond motifs, see: Bernstein et al. (1995). For related literature and applications see, for example: Goswami & Maity (2007); Taylor et al. (1989); Taylor & Ray (1988); Beer et al. (1993); Goswami et al. (2000, 2005); Fun et al. (2008).

Experimental top

Phosphorus oxychloride (POCl₃) (15 ml) was added to 2-amino-6-methylpyridine (2 g, 0.019 mmol) and the mixture was refluxed at 383 K for 16 h. Excess POCl₃ was distilled off. The solid residue was neutralized using KOH solution in an ice bath and a saturated NaHCO₃ solution was added. The solid residue was filtered off, extracted with CHCl₃, the solution was dried over anhydrous Na₂SO₄ and then concentrated under vacuum. The crude product was purified by column chromatography using silica gel with 20% ethyl acetate in petroleum ether as eluant to afford (I) (2.14 g, 65%) as a colourless crystalline solid, mp. 404–407 K.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Figures top

	Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids and the atomic numbering. Dashed lines show intramolecular hydrogen bonds.
	Fig. 2. The crystal packing for (I), showing dimers with R²₂(8) motifs and stacking of the dimers into columns along the b-axis. Intermolecular interactions are drawn as dashed lines.

3,5-Dichloro-6-methylpyridin-2-amine top

Crystal data top

C₆H₆Cl₂N₂	F(000) = 360
M_r = 177.03	D_x = 1.626 Mg m⁻³
Monoclinic, P2₁/n	Melting point: 404 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 12.7670 (3) Å	Cell parameters from 9896 reflections
b = 3.8037 (1) Å	θ = 2.4–40.3°
c = 15.4129 (3) Å	µ = 0.81 mm⁻¹
β = 104.990 (1)°	T = 100 K
V = 723.01 (3) Å³	Block, colourless
Z = 4	0.45 × 0.31 × 0.28 mm

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	3795 independent reflections
Radiation source: fine-focus sealed tube	3485 reflections with I > 2˘I)
Graphite monochromator	R_int = 0.026
ϕ and ω scans	θ_max = 37.5°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −21→21
T_min = 0.711, T_max = 0.803	k = −6→6
26531 measured reflections	l = −26→26

Refinement top

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)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.071	All H-atom parameters refined
S = 1.11	w = 1/[σ²(F_o²) + (0.037P)² + 0.1631P] where P = (F_o² + 2F_c²)/3
3795 reflections	(Δ/σ)_max = 0.001
115 parameters	Δρ_max = 0.61 e Å⁻³
0 restraints	Δρ_min = −0.42 e Å⁻³

Crystal data top

C₆H₆Cl₂N₂	V = 723.01 (3) Å³
M_r = 177.03	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 12.7670 (3) Å	µ = 0.81 mm⁻¹
b = 3.8037 (1) Å	T = 100 K
c = 15.4129 (3) Å	0.45 × 0.31 × 0.28 mm
β = 104.990 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	3795 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	3485 reflections with I > 2˘I)
T_min = 0.711, T_max = 0.803	R_int = 0.026
26531 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.024	0 restraints
wR(F²) = 0.071	All H-atom parameters refined
S = 1.11	Δρ_max = 0.61 e Å⁻³
3795 reflections	Δρ_min = −0.42 e Å⁻³
115 parameters

Special details top

Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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 > σ(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

	x	y	z	U_iso*/U_eq
Cl1	0.116608 (15)	0.89761 (5)	0.117299 (12)	0.01973 (5)
Cl2	0.150078 (13)	0.32687 (5)	−0.194719 (10)	0.01603 (4)
N1	0.36956 (5)	0.65340 (16)	0.02268 (4)	0.01455 (9)
N2	0.38950 (5)	0.41291 (19)	−0.10983 (4)	0.01738 (11)
H2N1	0.4571 (12)	0.379 (4)	−0.0819 (9)	0.027 (3)*
H1N1	0.3607 (11)	0.284 (4)	−0.1526 (9)	0.025 (3)*
C1	0.32310 (5)	0.51854 (18)	−0.05855 (4)	0.01322 (10)
C2	0.20904 (5)	0.49965 (17)	−0.08923 (4)	0.01321 (10)
C3	0.14544 (5)	0.61633 (18)	−0.03563 (4)	0.01465 (10)
H3	0.0672 (10)	0.605 (3)	−0.0583 (8)	0.022 (3)*
C4	0.19660 (5)	0.75331 (18)	0.04856 (4)	0.01450 (10)
C5	0.30903 (5)	0.77194 (18)	0.07629 (4)	0.01437 (10)
C6	0.37037 (7)	0.9165 (2)	0.16549 (5)	0.02130 (13)
H6C	0.4268 (13)	1.055 (5)	0.1579 (11)	0.041 (4)*
H6B	0.4079 (16)	0.744 (5)	0.2083 (12)	0.061 (5)*
H6A	0.3222 (16)	1.071 (6)	0.1929 (13)	0.065 (6)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.02170 (8)	0.02155 (8)	0.01862 (8)	0.00364 (6)	0.01006 (6)	−0.00108 (5)
Cl2	0.01665 (7)	0.01786 (7)	0.01167 (7)	−0.00132 (5)	0.00022 (5)	−0.00081 (5)
N1	0.0143 (2)	0.0174 (2)	0.0113 (2)	−0.00002 (17)	0.00219 (17)	−0.00112 (17)
N2	0.0146 (2)	0.0247 (3)	0.0127 (2)	0.00163 (19)	0.00317 (18)	−0.00292 (19)
C1	0.0136 (2)	0.0146 (2)	0.0110 (2)	0.00045 (18)	0.00251 (18)	0.00056 (18)
C2	0.0140 (2)	0.0139 (2)	0.0108 (2)	−0.00021 (18)	0.00163 (17)	0.00039 (18)
C3	0.0143 (2)	0.0153 (2)	0.0142 (2)	0.00085 (19)	0.00352 (19)	0.0011 (2)
C4	0.0168 (2)	0.0140 (2)	0.0137 (2)	0.0020 (2)	0.00586 (19)	0.00056 (19)
C5	0.0172 (2)	0.0141 (2)	0.0117 (2)	0.00022 (19)	0.00350 (19)	−0.00028 (19)
C6	0.0264 (3)	0.0224 (3)	0.0135 (3)	−0.0011 (3)	0.0023 (2)	−0.0044 (2)

Geometric parameters (Å, º) top

Cl1—C4	1.7396 (7)	C2—C3	1.3733 (9)
Cl2—C2	1.7346 (6)	C3—C4	1.3941 (9)
N1—C1	1.3409 (8)	C3—H3	0.970 (13)
N1—C5	1.3468 (9)	C4—C5	1.3894 (10)
N2—C1	1.3607 (9)	C5—C6	1.4996 (10)
N2—H2N1	0.869 (14)	C6—H6C	0.924 (17)
N2—H1N1	0.828 (14)	C6—H6B	0.96 (2)
C1—C2	1.4118 (9)	C6—H6A	1.02 (2)

C1—N1—C5	121.03 (6)	C5—C4—C3	120.23 (6)
C1—N2—H2N1	116.4 (9)	C5—C4—Cl1	121.27 (5)
C1—N2—H1N1	115.0 (9)	C3—C4—Cl1	118.50 (5)
H2N1—N2—H1N1	119.1 (13)	N1—C5—C4	120.35 (6)
N1—C1—N2	117.62 (6)	N1—C5—C6	116.03 (6)
N1—C1—C2	120.07 (6)	C4—C5—C6	123.62 (6)
N2—C1—C2	122.28 (6)	C5—C6—H6C	109.4 (10)
C3—C2—C1	120.08 (6)	C5—C6—H6B	115.3 (11)
C3—C2—Cl2	120.37 (5)	H6C—C6—H6B	102.0 (15)
C1—C2—Cl2	119.55 (5)	C5—C6—H6A	111.3 (11)
C2—C3—C4	118.24 (6)	H6C—C6—H6A	107.2 (15)
C2—C3—H3	118.9 (7)	H6B—C6—H6A	110.8 (14)
C4—C3—H3	122.8 (7)

C5—N1—C1—N2	178.27 (6)	C2—C3—C4—C5	0.46 (10)
C5—N1—C1—C2	0.13 (10)	C2—C3—C4—Cl1	−179.37 (5)
N1—C1—C2—C3	−0.61 (10)	C1—N1—C5—C4	0.64 (10)
N2—C1—C2—C3	−178.66 (7)	C1—N1—C5—C6	179.98 (6)
N1—C1—C2—Cl2	179.63 (5)	C3—C4—C5—N1	−0.94 (10)
N2—C1—C2—Cl2	1.58 (9)	Cl1—C4—C5—N1	178.89 (5)
C1—C2—C3—C4	0.29 (10)	C3—C4—C5—C6	179.77 (7)
Cl2—C2—C3—C4	−179.95 (5)	Cl1—C4—C5—C6	−0.40 (10)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N1···N1ⁱ	0.869 (15)	2.168 (15)	3.0320 (9)	172.8 (13)
N2—H1N1···Cl2	0.828 (14)	2.603 (14)	3.0156 (7)	112.3 (12)
C6—H6A···Cl1	1.02 (2)	2.67 (2)	3.1318 (9)	108.0 (14)
N2—H1N1···Cl2ⁱⁱ	0.828 (14)	2.900 (14)	3.6758 (7)	156.9 (13)

Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+1/2, y−1/2, −z−1/2.

Experimental details

Crystal data
Chemical formula	C₆H₆Cl₂N₂
M_r	177.03
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	100
a, b, c (Å)	12.7670 (3), 3.8037 (1), 15.4129 (3)
β (°)	104.990 (1)
V (Å³)	723.01 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.81
Crystal size (mm)	0.45 × 0.31 × 0.28

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.711, 0.803
No. of measured, independent and observed [I > 2˘I)] reflections	26531, 3795, 3485
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.857

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.024, 0.071, 1.11
No. of reflections	3795
No. of parameters	115
H-atom treatment	All H-atom parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.61, −0.42

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N1···N1ⁱ	0.869 (15)	2.168 (15)	3.0320 (9)	172.8 (13)
N2—H1N1···Cl2	0.828 (14)	2.603 (14)	3.0156 (7)	112.3 (12)
C6—H6A···Cl1	1.02 (2)	2.67 (2)	3.1318 (9)	108.0 (14)
N2—H1N1···Cl2ⁱⁱ	0.828 (14)	2.900 (14)	3.6758 (7)	156.9 (13)

Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+1/2, y−1/2, −z−1/2.

Acknowledgements

HKF and RK thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. RK thanks Universiti Sains Malaysia for a post-doctoral research fellowship. We thank the DST [SR/S1/OC-13/2005], Govt. of India, for financial support. ACM thanks the UGC, Govt. of India, for a fellowship. HKF also thanks Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

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