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

Miao, J.; Guo, J.; Hu, C.; Wang, D.; Nie, Y.

doi:10.1107/S1600536810004976

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 66| Part 3| March 2010| Page o603

doi:10.1107/S1600536810004976

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

Jinling Miao,^a Jisheng Guo,^a Chunhua Hu,^b Daqi Wang ^c and Yong Nie ^a ^*

^aSchool of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, People's Republic of China, ^bDepartment of Chemistry, New York University, 100 Washington Square East, New York, NY 10003-6688, USA, and ^cCollege of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, People's Republic of China
^*Correspondence e-mail: chm_niey@ujn.edu.cn

(Received 29 November 2009; accepted 8 February 2010; online 13 February 2010)

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

Experimental

Crystal data

C₇H₇N₂O⁺·I⁻
M_r = 262.05
Orthorhombic, P n m a
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 ) 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[F² > 2σ(F²)] = 0.036
wR(F²) = 0.103
S = 1.05
806 reflections
73 parameters
24 restraints
H-atom parameters constrained
Δρ_max = 0.70 e Å⁻³
Δρ_min = −0.93 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H2A⋯I1ⁱ	1.03	2.85	3.80 (2)	153
Symmetry code: (i) $[-x+{\script{1\over 2}}, -y, z-{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); 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.

Supporting information

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

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

checkCIF report

Comment top

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.

Related literature top

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

Experimental top

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.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); 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 (Sheldrick, 2008).

Figures top

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

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

Crystal data top

C₇H₇N₂O⁺·I⁻	D_x = 2.049 Mg m⁻³
M_r = 262.05	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pnma	Cell parameters from 1914 reflections
a = 14.597 (2) Å	θ = 2.5–27.2°
b = 8.2044 (18) Å	µ = 3.71 mm⁻¹
c = 7.0926 (15) Å	T = 298 K
V = 849.4 (3) Å³	Block, red
Z = 4	0.48 × 0.45 × 0.23 mm
F(000) = 496

Data collection top

Bruker SMART 1000 CCD area-detector diffractometer	806 independent reflections
Radiation source: fine-focus sealed tube	691 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.064
ω scans	θ_max = 25.0°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −17→13
T_min = 0.269, T_max = 0.482	k = −9→9
3631 measured reflections	l = −5→8

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.103	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.0619P)² + 0.9786P] where P = (F_o² + 2F_c²)/3
806 reflections	(Δ/σ)_max < 0.001
73 parameters	Δρ_max = 0.70 e Å⁻³
24 restraints	Δρ_min = −0.93 e Å⁻³

Crystal data top

C₇H₇N₂O⁺·I⁻	V = 849.4 (3) Å³
M_r = 262.05	Z = 4
Orthorhombic, Pnma	Mo Kα radiation
a = 14.597 (2) Å	µ = 3.71 mm⁻¹
b = 8.2044 (18) Å	T = 298 K
c = 7.0926 (15) Å	0.48 × 0.45 × 0.23 mm

Data collection top

Bruker SMART 1000 CCD area-detector diffractometer	806 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2001)	691 reflections with I > 2σ(I)
T_min = 0.269, T_max = 0.482	R_int = 0.064
3631 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	24 restraints
wR(F²) = 0.103	H-atom parameters constrained
S = 1.05	Δρ_max = 0.70 e Å⁻³
806 reflections	Δρ_min = −0.93 e Å⁻³
73 parameters

Special details top

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) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
I1	0.41289 (4)	0.2500	0.91066 (7)	0.0537 (3)
C4	0.1109 (3)	0.0822 (7)	0.9883 (8)	0.0519 (13)
H4	0.1112	−0.0311	0.9844	0.062*
C5	0.0758 (4)	0.1656 (8)	1.1372 (9)	0.0551 (14)
H5	0.0517	0.1091	1.2395	0.066*
O1	0.2504 (5)	0.2500	0.4103 (7)	0.0724 (19)
C1	0.2120 (6)	0.2500	0.5605 (11)	0.053 (2)
C2	0.184 (3)	0.103 (3)	0.674 (4)	0.050 (9)	0.50
H2A	0.1384	0.0386	0.6073	0.060*	0.50
H2B	0.2363	0.0342	0.7024	0.060*	0.50
N2	0.146 (4)	0.174 (3)	0.846 (4)	0.039 (8)	0.50
N1	0.186 (2)	0.1164 (19)	0.666 (3)	0.049 (7)	0.50
H1	0.1935	0.0170	0.6309	0.058*	0.50
C3	0.146 (4)	0.161 (4)	0.831 (5)	0.037 (8)	0.50

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
I1	0.0550 (4)	0.0434 (4)	0.0627 (4)	0.000	−0.0103 (2)	0.000
C4	0.044 (3)	0.044 (3)	0.068 (3)	0.002 (2)	−0.003 (3)	0.009 (3)
C5	0.046 (3)	0.064 (4)	0.056 (3)	0.000 (2)	−0.001 (2)	0.013 (3)
O1	0.070 (4)	0.099 (5)	0.049 (3)	0.000	0.003 (3)	0.000
C1	0.047 (5)	0.058 (5)	0.053 (5)	0.000	−0.004 (4)	0.000
C2	0.054 (13)	0.039 (10)	0.057 (12)	−0.006 (8)	0.009 (8)	0.005 (8)
N2	0.032 (10)	0.040 (9)	0.047 (9)	0.004 (7)	−0.003 (7)	−0.002 (6)
N1	0.047 (11)	0.042 (9)	0.058 (11)	0.003 (8)	−0.016 (8)	−0.019 (7)
C3	0.030 (11)	0.034 (10)	0.048 (10)	−0.002 (6)	−0.010 (7)	−0.006 (6)

Geometric parameters (Å, º) top

C4—N2	1.357 (9)	C1—N1ⁱ	1.381 (9)
C4—C5	1.358 (9)	C1—C2	1.509 (10)
C4—C3	1.387 (9)	C1—C2ⁱ	1.509 (10)
C4—H4	0.9300	C2—N2	1.461 (10)
C5—C5ⁱ	1.386 (14)	C2—H2A	0.9700
C5—H5	0.9300	C2—H2B	0.9700
O1—C1	1.204 (9)	N1—C3	1.360 (10)
C1—N1	1.381 (9)	N1—H1	0.8600

N2—C4—C5	116.2 (14)	O1—C1—C2ⁱ	126.8 (12)
N2—C4—C3	6 (3)	N1—C1—C2ⁱ	105.8 (7)
C5—C4—C3	121.9 (16)	N1ⁱ—C1—C2ⁱ	1 (3)
N2—C4—H4	121.9	C2—C1—C2ⁱ	106 (2)
C5—C4—H4	121.9	N2—C2—C1	103.3 (11)
C3—C4—H4	116.2	N2—C2—H2A	111.1
C4—C5—C5ⁱ	120.2 (4)	C1—C2—H2A	111.1
C4—C5—H5	119.9	N2—C2—H2B	111.1
C5ⁱ—C5—H5	119.9	C1—C2—H2B	111.1
O1—C1—N1	127.5 (10)	H2A—C2—H2B	109.1
O1—C1—N1ⁱ	127.5 (10)	C4—N2—C2	122.9 (19)
N1—C1—N1ⁱ	105 (2)	C3—N1—C1	111.7 (10)
O1—C1—C2	126.8 (12)	C3—N1—H1	124.1
N1—C1—C2	1 (3)	C1—N1—H1	124.1
N1ⁱ—C1—C2	105.8 (7)	N1—C3—C4	136 (2)

Symmetry code: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H2A···I1ⁱⁱ	1.03	2.85	3.80 (2)	153

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

Experimental details

Crystal data
Chemical formula	C₇H₇N₂O⁺·I⁻
M_r	262.05
Crystal system, space group	Orthorhombic, Pnma
Temperature (K)	298
a, b, c (Å)	14.597 (2), 8.2044 (18), 7.0926 (15)
V (Å³)	849.4 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	3.71
Crystal size (mm)	0.48 × 0.45 × 0.23

Data collection
Diffractometer	Bruker SMART 1000 CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2001)
T_min, T_max	0.269, 0.482
No. of measured, independent and observed [I > 2σ(I)] reflections	3631, 806, 691
R_int	0.064
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.103, 1.05
No. of reflections	806
No. of parameters	73
No. of restraints	24
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.70, −0.93

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H2A···I1ⁱ	1.03	2.85	3.80 (2)	153

Symmetry code: (i) −x+1/2, −y, z−1/2.

Acknowledgements

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.

References

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