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Acta Crystallogr Sect E Struct Rep Online. 2009 December 1; 65(Pt 12): o3269.
Published online 2009 November 28. doi:  10.1107/S1600536809050739
PMCID: PMC2971865

2-Iodo-3-meth­oxy-6-methyl­pyridine

Abstract

The title compound, C7H8INO, which crystallizes with three independent mol­ecules in the asymmetric unit, was prepared by the reaction of 3-meth­oxy-6-methyl­pyridine with KI and I2 in tetra­hydro­furan solution. In the crystal structure, the three independent mol­ecules are arranged in a similar orientation with the three polar meth­oxy groups aligned on one side and the three non-polar methyl groups on the other side. The three mol­ecules, excluding methyl H atoms, are essentially planar, with r.m.s. deviations of 0.0141 (1), 0.0081 (1) and 0.0066 (2)Å. The three pyridine rings make dihedral angles of 58.09 (3) 66.64 (4) and 71.5 (3)°. The crystal structure features rather weak inter­molecular C—H(...)O hydrogen bonds, which link two mol­ecules into dimers, and short I(...)N contacts [4.046 (3) Å].

Related literature

For C—C bond formation reactions, see: Vlad & Horvath (2002 [triangle]). For related structures, see: Bunker et al. (2009 [triangle]); Tahir et al. (2009 [triangle]).

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Object name is e-65-o3269-scheme1.jpg

Experimental

Crystal data

  • C7H8INO
  • M r = 249.04
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o3269-efi1.jpg
  • a = 7.7974 (9) Å
  • b = 10.8302 (12) Å
  • c = 16.2898 (18) Å
  • α = 106.093 (1)°
  • β = 90.633 (1)°
  • γ = 103.636 (1)°
  • V = 1280.2 (2) Å3
  • Z = 6
  • Mo Kα radiation
  • μ = 3.69 mm−1
  • T = 296 K
  • 0.20 × 0.14 × 0.13 mm

Data collection

  • Bruker APEXII CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.526, T max = 0.646
  • 9886 measured reflections
  • 4737 independent reflections
  • 3719 reflections with I > 2σ(I)
  • R int = 0.026

Refinement

  • R[F 2 > 2σ(F 2)] = 0.029
  • wR(F 2) = 0.062
  • S = 1.01
  • 4737 reflections
  • 278 parameters
  • H-atom parameters constrained
  • Δρmax = 0.56 e Å−3
  • Δρmin = −0.68 e Å−3

Data collection: APEX2 (Bruker, 2004 [triangle]); cell refinement: SAINT (Bruker, 2004 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]) and DIAMOND (Brandenburg, 2006 [triangle]); software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809050739/bq2179sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809050739/bq2179Isup2.hkl

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

Acknowledgments

This work was supported by the Doctoral Foundation and Cultivatable Foundation (2008-PYJJ-011) of Luoyang Normal University.

supplementary crystallographic information

Comment

As is known, the Ullmann coupling reaction is an important C—C bond formation reaction. In this reaction, the halogen derivatives of aromatic compounds have been used as its reaction substrates (Vlad & Horvath. 2002). The reaction of 3-methoxy-6-methylpyridine with KI and I2 in the presence of NaHCO3 leads to iodo-substitution at position 2 of the pyridine ring with similar structure to the previous compound (Bunker et al. 2009), as shown by the X-ray study of the title compound (Fig. 1).

The asymmetric unit consists of three neutral C7H8INO molecules, in which the bond lengths and angles are within normal ranges (Bunker et al. 2009; Tahir et al. 2009). In the crystal structure, the three molecules are arranged in the similar orientation with the three polar methoxy groups aligning on one side and the three non-polar methyl groups siding on the other side. The pyridine ring 1 (C1-C5/N1) forms dihedral angles of 58.09 (3)° and 66.64 (4)°, respectively, with the pyridine ring 2 (C8-C12/N2) and the pyridine ring 3 (C15-19/N3). Rings 2 and 3 form a dihedral angle of 71.5 (3)°. Furthermore, the organic molecules, excluding methyl H atoms, are essentially planar, with r.m.s. deviations of 0.0141 (1), 0.0081 (1) and 0.0066 (2) Å. There are no strong halogen···halogen interactions in the structure, the shortest intermolecular I—I distances are 4.266 (2)Å. However, intermolecular C—H···O hydrogen bonds link the molecules into dimers, in which C14—H14B is donor and O2 is acceptor (Table 1, Fig. 2). This weak contacts may be effective in the stabilization of the structure.

Experimental

To a solution of 3-methoxy-6-methylpyridine (4.00 g, 30 mmol) in THF 30 ml was added 10 ml water containing 2.69 g NaHCO3 (32 mmol). The mixture was stirred for 30 minutes. Under ice bath, the resulting solution was added dropwise a solution of I2 (8.12 g, 32 mmol) and KI (5.31 g, 32 mmol) in water (75 ml). The mixture was then stirred 72 h at room temperature, and treated with 15° solution of sodium thiosulfate, then filtered. The resulting white solid was rinsed with ice water, and dried under vacuum to afford 2-iodo-3-methoxy-6-methylpyridine, 6.48 g, 89.7° yield. The crystalline compound was obtained through the slow volatilization of ethyl acetate containing the title compound.

Refinement

All H atoms were positioned geometrically and treated as riding, with C—H bond lengths constrained to 0.93 Å (aromatic CH), 0.96 Å (methyl CH3), and with Uĩso~(H) = 1.2Ueq(C) or 1.5Ueq(methyl).

Figures

Fig. 1.
View of (I) (three molecule in the asymmetric unit) with atom numbering scheme and 30% probability displacement ellipsoids for non-hydrogen atoms.
Fig. 2.
View of the dimers (C—H···O hydrogen bonds are indicated as broken lines).

Crystal data

C7H8INOZ = 6
Mr = 249.04F(000) = 708
Triclinic, P1Dx = 1.938 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.7974 (9) ÅCell parameters from 3296 reflections
b = 10.8302 (12) Åθ = 2.7–23.1°
c = 16.2898 (18) ŵ = 3.69 mm1
α = 106.093 (1)°T = 296 K
β = 90.633 (1)°Block, colorless
γ = 103.636 (1)°0.20 × 0.14 × 0.13 mm
V = 1280.2 (2) Å3

Data collection

Bruker APEXII CCD diffractometer4737 independent reflections
Radiation source: fine-focus sealed tube3719 reflections with I > 2σ(I)
graphiteRint = 0.026
phi and ω scansθmax = 25.5°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −9→9
Tmin = 0.526, Tmax = 0.646k = −12→13
9886 measured reflectionsl = −19→19

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.029H-atom parameters constrained
wR(F2) = 0.062w = 1/[σ2(Fo2) + (0.0183P)2 + 0.8733P] where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max = 0.001
4737 reflectionsΔρmax = 0.56 e Å3
278 parametersΔρmin = −0.68 e Å3
0 restraintsExtinction correction: SHELXS97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0067 (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 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)

xyzUiso*/Ueq
C10.2655 (6)0.5314 (4)0.5640 (3)0.0522 (10)
C20.3438 (6)0.6096 (5)0.5130 (3)0.0581 (11)
C30.3160 (7)0.5495 (6)0.4251 (3)0.0776 (15)
H30.36330.59570.38700.093*
C40.2179 (7)0.4212 (6)0.3958 (3)0.0801 (15)
H40.20100.37970.33710.096*
C50.1440 (6)0.3525 (5)0.4509 (3)0.0652 (13)
C60.0322 (8)0.2131 (5)0.4196 (3)0.0905 (17)
H6A0.08960.15500.43800.136*
H6B0.01670.18660.35810.136*
H6C−0.08130.20840.44250.136*
C70.5208 (8)0.8131 (5)0.4975 (4)0.0900 (17)
H7A0.59240.76530.46000.135*
H7B0.59380.89610.53210.135*
H7C0.43110.82940.46390.135*
C80.5213 (6)0.3742 (4)0.0739 (2)0.0479 (10)
C90.6383 (6)0.4983 (4)0.0899 (3)0.0500 (10)
C100.5793 (7)0.6050 (4)0.1397 (3)0.0627 (12)
H100.65210.69060.15410.075*
C110.4127 (7)0.5816 (5)0.1669 (3)0.0671 (13)
H110.37250.65210.20040.081*
C120.3034 (6)0.4552 (5)0.1456 (3)0.0596 (11)
C130.1181 (7)0.4251 (5)0.1713 (3)0.0791 (15)
H13A0.03640.41200.12330.119*
H13B0.10290.49790.21760.119*
H13C0.09590.34600.18940.119*
C140.9152 (7)0.6345 (4)0.0738 (3)0.0765 (15)
H14A0.85910.69080.05270.115*
H14B1.02160.62760.04580.115*
H14C0.94380.67150.13450.115*
C150.1107 (5)0.9067 (4)0.2665 (2)0.0450 (9)
C160.2909 (5)0.9519 (4)0.2630 (3)0.0483 (10)
C170.3429 (6)1.0324 (4)0.2107 (3)0.0624 (12)
H170.46271.06600.20630.075*
C180.2179 (7)1.0628 (4)0.1653 (3)0.0646 (12)
H180.25281.11830.13080.077*
C190.0416 (6)1.0116 (4)0.1705 (3)0.0594 (11)
C20−0.1023 (7)1.0386 (6)0.1207 (4)0.0880 (17)
H20A−0.18290.95610.09030.132*
H20B−0.05051.08400.08070.132*
H20C−0.16521.09280.15960.132*
C210.5866 (6)0.9547 (5)0.3028 (4)0.0871 (17)
H21A0.60980.92760.24360.131*
H21B0.64990.91510.33510.131*
H21C0.62481.04950.32470.131*
I10.30556 (5)0.61072 (3)0.698542 (19)0.07157 (13)
I20.60344 (4)0.20520 (3)0.00399 (2)0.06819 (12)
I30.01400 (4)0.78330 (3)0.344715 (19)0.05933 (11)
N10.1683 (5)0.4079 (4)0.5349 (2)0.0568 (9)
N20.3602 (5)0.3508 (3)0.0991 (2)0.0538 (9)
N3−0.0123 (4)0.9329 (3)0.2220 (2)0.0526 (9)
O10.4377 (4)0.7353 (3)0.5523 (2)0.0727 (9)
O20.7978 (4)0.5059 (3)0.05666 (19)0.0619 (8)
O30.3999 (4)0.9124 (3)0.3106 (2)0.0648 (8)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.059 (3)0.060 (3)0.043 (2)0.024 (2)0.006 (2)0.016 (2)
C20.058 (3)0.071 (3)0.058 (3)0.027 (2)0.010 (2)0.028 (2)
C30.080 (4)0.103 (4)0.060 (3)0.028 (3)0.011 (3)0.036 (3)
C40.096 (4)0.098 (4)0.043 (3)0.029 (4)0.001 (3)0.012 (3)
C50.065 (3)0.071 (3)0.056 (3)0.024 (3)−0.006 (2)0.005 (2)
C60.106 (4)0.082 (4)0.069 (3)0.022 (3)−0.012 (3)0.000 (3)
C70.091 (4)0.091 (4)0.104 (4)0.014 (3)0.018 (3)0.061 (4)
C80.062 (3)0.040 (2)0.045 (2)0.017 (2)−0.005 (2)0.0143 (18)
C90.061 (3)0.042 (2)0.046 (2)0.013 (2)−0.008 (2)0.0104 (19)
C100.081 (3)0.043 (2)0.060 (3)0.016 (2)0.002 (3)0.008 (2)
C110.092 (4)0.058 (3)0.058 (3)0.034 (3)0.009 (3)0.014 (2)
C120.065 (3)0.069 (3)0.056 (3)0.028 (3)0.005 (2)0.026 (2)
C130.076 (4)0.100 (4)0.074 (3)0.035 (3)0.017 (3)0.035 (3)
C140.079 (4)0.053 (3)0.079 (3)−0.005 (3)0.003 (3)0.008 (3)
C150.046 (2)0.035 (2)0.050 (2)0.0075 (18)0.0084 (19)0.0084 (18)
C160.045 (2)0.039 (2)0.058 (3)0.0087 (19)0.004 (2)0.0093 (19)
C170.052 (3)0.047 (3)0.083 (3)0.003 (2)0.017 (2)0.017 (2)
C180.068 (3)0.052 (3)0.077 (3)0.006 (2)0.015 (3)0.032 (2)
C190.069 (3)0.050 (3)0.058 (3)0.011 (2)0.002 (2)0.017 (2)
C200.083 (4)0.095 (4)0.098 (4)0.016 (3)−0.008 (3)0.054 (3)
C210.047 (3)0.090 (4)0.128 (5)0.012 (3)0.003 (3)0.041 (4)
I10.0894 (3)0.0652 (2)0.04841 (18)0.00163 (17)0.00875 (16)0.01222 (15)
I20.0630 (2)0.03952 (17)0.0968 (3)0.01431 (14)0.00303 (17)0.01007 (16)
I30.05512 (19)0.0623 (2)0.0677 (2)0.01301 (14)0.01072 (14)0.03120 (15)
N10.064 (2)0.057 (2)0.050 (2)0.0183 (19)0.0019 (18)0.0131 (18)
N20.057 (2)0.056 (2)0.057 (2)0.0195 (18)0.0023 (18)0.0244 (18)
N30.049 (2)0.045 (2)0.061 (2)0.0090 (16)0.0021 (17)0.0147 (17)
O10.079 (2)0.066 (2)0.076 (2)0.0091 (18)0.0111 (18)0.0331 (18)
O20.0599 (19)0.0423 (16)0.0701 (19)0.0027 (14)0.0029 (16)0.0033 (14)
O30.0402 (16)0.069 (2)0.087 (2)0.0107 (15)0.0047 (15)0.0270 (17)

Geometric parameters (Å, °)

C1—N11.323 (5)C12—N21.348 (5)
C1—C21.392 (6)C12—C131.496 (6)
C1—I12.110 (4)C13—H13A0.9600
C2—O11.355 (5)C13—H13B0.9600
C2—C31.390 (6)C13—H13C0.9600
C3—C41.366 (7)C14—O21.426 (5)
C3—H30.9300C14—H14A0.9600
C4—C51.368 (7)C14—H14B0.9600
C4—H40.9300C14—H14C0.9600
C5—N11.324 (5)C15—N31.324 (5)
C5—C61.497 (7)C15—C161.382 (5)
C6—H6A0.9600C15—I32.114 (4)
C6—H6B0.9600C16—O31.359 (5)
C6—H6C0.9600C16—C171.380 (6)
C7—O11.449 (5)C17—C181.369 (6)
C7—H7A0.9600C17—H170.9300
C7—H7B0.9600C18—C191.369 (6)
C7—H7C0.9600C18—H180.9300
C8—N21.315 (5)C19—N31.357 (5)
C8—C91.389 (5)C19—C201.506 (6)
C8—I22.115 (4)C20—H20A0.9600
C9—O21.356 (5)C20—H20B0.9600
C9—C101.394 (6)C20—H20C0.9600
C10—C111.367 (6)C21—O31.438 (5)
C10—H100.9300C21—H21A0.9600
C11—C121.379 (6)C21—H21B0.9600
C11—H110.9300C21—H21C0.9600
N1—C1—C2125.0 (4)H13A—C13—H13B109.5
N1—C1—I1116.1 (3)C12—C13—H13C109.5
C2—C1—I1118.9 (3)H13A—C13—H13C109.5
O1—C2—C3126.1 (4)H13B—C13—H13C109.5
O1—C2—C1118.2 (4)O2—C14—H14A109.5
C3—C2—C1115.6 (5)O2—C14—H14B109.5
C4—C3—C2118.8 (5)H14A—C14—H14B109.5
C4—C3—H3120.6O2—C14—H14C109.5
C2—C3—H3120.6H14A—C14—H14C109.5
C3—C4—C5121.4 (5)H14B—C14—H14C109.5
C3—C4—H4119.3N3—C15—C16124.5 (4)
C5—C4—H4119.3N3—C15—I3115.2 (3)
N1—C5—C4120.8 (5)C16—C15—I3120.3 (3)
N1—C5—C6117.3 (5)O3—C16—C17126.2 (4)
C4—C5—C6122.0 (5)O3—C16—C15117.2 (4)
C5—C6—H6A109.5C17—C16—C15116.6 (4)
C5—C6—H6B109.5C18—C17—C16119.8 (4)
H6A—C6—H6B109.5C18—C17—H17120.1
C5—C6—H6C109.5C16—C17—H17120.1
H6A—C6—H6C109.5C19—C18—C17120.2 (4)
H6B—C6—H6C109.5C19—C18—H18119.9
O1—C7—H7A109.5C17—C18—H18119.9
O1—C7—H7B109.5N3—C19—C18120.8 (4)
H7A—C7—H7B109.5N3—C19—C20116.4 (4)
O1—C7—H7C109.5C18—C19—C20122.8 (4)
H7A—C7—H7C109.5C19—C20—H20A109.5
H7B—C7—H7C109.5C19—C20—H20B109.5
N2—C8—C9125.6 (4)H20A—C20—H20B109.5
N2—C8—I2115.6 (3)C19—C20—H20C109.5
C9—C8—I2118.8 (3)H20A—C20—H20C109.5
O2—C9—C8118.2 (4)H20B—C20—H20C109.5
O2—C9—C10125.8 (4)O3—C21—H21A109.5
C8—C9—C10116.0 (4)O3—C21—H21B109.5
C11—C10—C9118.9 (4)H21A—C21—H21B109.5
C11—C10—H10120.6O3—C21—H21C109.5
C9—C10—H10120.6H21A—C21—H21C109.5
C10—C11—C12121.0 (4)H21B—C21—H21C109.5
C10—C11—H11119.5C1—N1—C5118.3 (4)
C12—C11—H11119.5C8—N2—C12117.8 (4)
N2—C12—C11120.6 (4)C15—N3—C19118.0 (4)
N2—C12—C13116.3 (4)C2—O1—C7116.9 (4)
C11—C12—C13123.1 (4)C9—O2—C14117.1 (3)
C12—C13—H13A109.5C16—O3—C21116.5 (4)
C12—C13—H13B109.5
N1—C1—C2—O1179.0 (4)C15—C16—C17—C18−0.4 (6)
I1—C1—C2—O1−2.2 (5)C16—C17—C18—C19−1.1 (7)
N1—C1—C2—C3−0.6 (7)C17—C18—C19—N31.5 (7)
I1—C1—C2—C3178.2 (3)C17—C18—C19—C20−178.5 (5)
O1—C2—C3—C4179.9 (5)C2—C1—N1—C50.8 (6)
C1—C2—C3—C4−0.5 (7)I1—C1—N1—C5−178.0 (3)
C2—C3—C4—C51.5 (8)C4—C5—N1—C10.1 (7)
C3—C4—C5—N1−1.3 (8)C6—C5—N1—C1−179.5 (4)
C3—C4—C5—C6178.4 (5)C9—C8—N2—C12−1.1 (6)
N2—C8—C9—O2−177.6 (4)I2—C8—N2—C12178.5 (3)
I2—C8—C9—O22.8 (5)C11—C12—N2—C8−1.1 (6)
N2—C8—C9—C102.5 (6)C13—C12—N2—C8178.6 (4)
I2—C8—C9—C10−177.2 (3)C16—C15—N3—C19−1.5 (6)
O2—C9—C10—C11178.5 (4)I3—C15—N3—C19−180.0 (3)
C8—C9—C10—C11−1.6 (6)C18—C19—N3—C15−0.3 (6)
C9—C10—C11—C12−0.4 (7)C20—C19—N3—C15179.8 (4)
C10—C11—C12—N21.8 (7)C3—C2—O1—C7−1.8 (7)
C10—C11—C12—C13−177.9 (4)C1—C2—O1—C7178.7 (4)
N3—C15—C16—O3−177.8 (3)C8—C9—O2—C14179.8 (4)
I3—C15—C16—O30.7 (5)C10—C9—O2—C14−0.3 (6)
N3—C15—C16—C171.8 (6)C17—C16—O3—C21−2.6 (6)
I3—C15—C16—C17−179.7 (3)C15—C16—O3—C21177.0 (4)
O3—C16—C17—C18179.1 (4)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C14—H14B···O2i0.962.563.429 (6)151

Symmetry codes: (i) −x+2, −y+1, −z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BQ2179).

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