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Acta Crystallogr Sect E Struct Rep Online. 2010 March 1; 66(Pt 3): o603.
Published online 2010 February 13. doi:  10.1107/S1600536810004976
PMCID: PMC2983633

2-Oxo-2,3-dihydro-1H-imidazo[1,2-a]pyridinium iodide

Abstract

In the title compound, C7H7N2O+·I, the carbonyl C and O atoms of the cation and the iodide ion are situated on mirror planes. The mean plane of the imidazo[1,2-d]pyridinium cation is perpendicular to the mirror plane as a consequence of the disorder of the cation over two opposite orientations of equal occupancy. In the crystal, N—H(...)I interactions are present.

Related literature

For the synthesis of imidazo[1,2-a]pyridinium chloride or bromide, see: Newton et al. (1984 [triangle]); Baumann et al. (1986 [triangle]). For the derivatization of imidazo[1,2-a]pyridinium and related structures, see: Plutecka et al. (2006 [triangle]); Hoffmann et al. (2005 [triangle]); Qiao et al. (2006 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-0o603-scheme1.jpg

Experimental

Crystal data

  • C7H7N2O+·I
  • M r = 262.05
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-66-0o603-efi2.jpg
  • a = 14.597 (2) Å
  • b = 8.2044 (18) Å
  • c = 7.0926 (15) Å
  • V = 849.4 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 3.71 mm−1
  • T = 298 K
  • 0.48 × 0.45 × 0.23 mm

Data collection

  • Bruker SMART 1000 CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2001 [triangle]) T min = 0.269, T max = 0.482
  • 3631 measured reflections
  • 806 independent reflections
  • 691 reflections with I > 2σ(I)
  • R int = 0.064

Refinement

  • R[F 2 > 2σ(F 2)] = 0.036
  • wR(F 2) = 0.103
  • S = 1.05
  • 806 reflections
  • 73 parameters
  • 24 restraints
  • H-atom parameters constrained
  • Δρmax = 0.70 e Å−3
  • Δρmin = −0.93 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [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]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810004976/cv2672sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810004976/cv2672Isup2.hkl

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

Acknowledgments

The authors thank the University of Jinan (grant No. B0605) and the Key Subject Research Foundation of Shandong Province (grant No. XTD 0704) for support.

supplementary crystallographic information

Comment

Imidazo[1,2-a]pyridine derivatives have been investigated as important intermediates in organic synthesis and useful agents in medicinal chemistry. Imidazo[1,2-a]pyridinium chloride or bromide is accessible from the reaction of alkyl haloacetate with 2-aminopyridine compounds (Newton et al., 1984; Baumann et al., 1986), and can be further derivatised (Plutecka et al., 2006; Hoffmann et al., 2005). The reaction of 2-aminopyridine and chloroacetic acid under basic condition gave rise to, after acidification, 3,3-bis(carboxymethyl) imidazo[1,2-a]pyridine-2-one (Qiao et al., 2006). Here we report on the synthesis and structure of the title compound (I), which was obtained from the reaction of iodoacetic acid with 2-aminopyridine under basic condition.

The structure of (I) (Fig. 1) consists of imidazo[1,2-a]pyridinium cations and iodide anions. In the cation, the six-membered and five-membered rings are coplanar with a dihedral angle of 0.48°. However, the four C/N atoms in the ring system (Fig. 1) are found to be disordered. The structure may be seen as two molecules being in one crystallographic position, with an occupancy of 0.5 for each C/N atom involved. Thus, in one molecule the five-membered ring is N2/C2/C1/N1a/C3a, and in another molecule - C3/N1/C1/C2a/N2a.

Experimental

A mixture of 2-aminopyridine (1.132 g, 0.012 mol), ICH2COOH (5.592 g, 0.030 mol) and Na2CO3 (2.549 g, 0.024 mol) was placed in 60 ml of distilled water. After the evolution of bubbles was over, the mixture of was heated at reflux for 6 h, while the pH was adjusted to 8–9 using aqueous NaOH (0.1 mol/l) solution, at a time interval of 0.5 h. The resulting deep red solution was cooled to room temperature and acidified with hydrochloric acid till pH 2–3 (during which some red solid was formed, but could be dissolved on warming to 40°C). On standing still at room temperature, deep red crystals were grown after one month. IR (KBr): 3465, 3076, 1751, 1650, 1511, 1330, 1185, 792, 608 cm-1.

Refinement

All H atoms were positioned geometrically and refined using a riding model with C—H = 0.93–0.97 Å, N—H = 0.86 Å, Uiso(H) = 1.2Ueq(C,N).

Figures

Fig. 1.
The molecular structure, with atom labels and 25% probability displacement ellipsoids [symmetry code: (a) x, 1/2 - y, z].

Crystal data

C7H7N2O+·IDx = 2.049 Mg m3
Mr = 262.05Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PnmaCell parameters from 1914 reflections
a = 14.597 (2) Åθ = 2.5–27.2°
b = 8.2044 (18) ŵ = 3.71 mm1
c = 7.0926 (15) ÅT = 298 K
V = 849.4 (3) Å3Block, red
Z = 40.48 × 0.45 × 0.23 mm
F(000) = 496

Data collection

Bruker SMART 1000 CCD area-detector diffractometer806 independent reflections
Radiation source: fine-focus sealed tube691 reflections with I > 2σ(I)
graphiteRint = 0.064
ω scansθmax = 25.0°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2001)h = −17→13
Tmin = 0.269, Tmax = 0.482k = −9→9
3631 measured reflectionsl = −5→8

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.103H-atom parameters constrained
S = 1.05w = 1/[σ2(Fo2) + (0.0619P)2 + 0.9786P] where P = (Fo2 + 2Fc2)/3
806 reflections(Δ/σ)max < 0.001
73 parametersΔρmax = 0.70 e Å3
24 restraintsΔρmin = −0.93 e Å3

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/UeqOcc. (<1)
I10.41289 (4)0.25000.91066 (7)0.0537 (3)
C40.1109 (3)0.0822 (7)0.9883 (8)0.0519 (13)
H40.1112−0.03110.98440.062*
C50.0758 (4)0.1656 (8)1.1372 (9)0.0551 (14)
H50.05170.10911.23950.066*
O10.2504 (5)0.25000.4103 (7)0.0724 (19)
C10.2120 (6)0.25000.5605 (11)0.053 (2)
C20.184 (3)0.103 (3)0.674 (4)0.050 (9)0.50
H2A0.13840.03860.60730.060*0.50
H2B0.23630.03420.70240.060*0.50
N20.146 (4)0.174 (3)0.846 (4)0.039 (8)0.50
N10.186 (2)0.1164 (19)0.666 (3)0.049 (7)0.50
H10.19350.01700.63090.058*0.50
C30.146 (4)0.161 (4)0.831 (5)0.037 (8)0.50

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
I10.0550 (4)0.0434 (4)0.0627 (4)0.000−0.0103 (2)0.000
C40.044 (3)0.044 (3)0.068 (3)0.002 (2)−0.003 (3)0.009 (3)
C50.046 (3)0.064 (4)0.056 (3)0.000 (2)−0.001 (2)0.013 (3)
O10.070 (4)0.099 (5)0.049 (3)0.0000.003 (3)0.000
C10.047 (5)0.058 (5)0.053 (5)0.000−0.004 (4)0.000
C20.054 (13)0.039 (10)0.057 (12)−0.006 (8)0.009 (8)0.005 (8)
N20.032 (10)0.040 (9)0.047 (9)0.004 (7)−0.003 (7)−0.002 (6)
N10.047 (11)0.042 (9)0.058 (11)0.003 (8)−0.016 (8)−0.019 (7)
C30.030 (11)0.034 (10)0.048 (10)−0.002 (6)−0.010 (7)−0.006 (6)

Geometric parameters (Å, °)

C4—N21.357 (9)C1—N1i1.381 (9)
C4—C51.358 (9)C1—C21.509 (10)
C4—C31.387 (9)C1—C2i1.509 (10)
C4—H40.9300C2—N21.461 (10)
C5—C5i1.386 (14)C2—H2A0.9700
C5—H50.9300C2—H2B0.9700
O1—C11.204 (9)N1—C31.360 (10)
C1—N11.381 (9)N1—H10.8600
N2—C4—C5116.2 (14)O1—C1—C2i126.8 (12)
N2—C4—C36(3)N1—C1—C2i105.8 (7)
C5—C4—C3121.9 (16)N1i—C1—C2i1(3)
N2—C4—H4121.9C2—C1—C2i106 (2)
C5—C4—H4121.9N2—C2—C1103.3 (11)
C3—C4—H4116.2N2—C2—H2A111.1
C4—C5—C5i120.2 (4)C1—C2—H2A111.1
C4—C5—H5119.9N2—C2—H2B111.1
C5i—C5—H5119.9C1—C2—H2B111.1
O1—C1—N1127.5 (10)H2A—C2—H2B109.1
O1—C1—N1i127.5 (10)C4—N2—C2122.9 (19)
N1—C1—N1i105 (2)C3—N1—C1111.7 (10)
O1—C1—C2126.8 (12)C3—N1—H1124.1
N1—C1—C21(3)C1—N1—H1124.1
N1i—C1—C2105.8 (7)N1—C3—C4136 (2)

Symmetry codes: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N1—H2A···I1ii1.032.853.80 (2)153

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV2672).

References

  • Baumann, M. E., Bosshard, H., Breitenstein, W. & Rist, G. (1986). Helv. Chim. Acta, 69, 396–403.
  • Bruker (2001). SMART, SAINT and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Hoffmann, M., Plutecka, A., Rychlewska, K., Kucybala, Z., Paczkowski, J. & Pyszka, I. (2005). J. Phys. Chem. A, 109, 4568–4574. [PubMed]
  • Newton, C. G., Ollis, W. D. & Wright, D. E. (1984). J. Chem. Soc. Perkin Trans. 1, pp. 69–73.
  • Plutecka, A., Hoffmann, M., Rychlewska, U., Kucybała, Z., Pączkowski, J. & Pyszka, I. (2006). Acta Cryst. B62, 135–142. [PubMed]
  • Qiao, S., Yong, G.-P., Xie, Y. & Wang, Z.-Y. (2006). Acta Cryst. E62, o4634–o4635.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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