Crystal structure of dimeth­yl[(E)-2-(1-methyl-5-nitro-1H-imidazol-4-yl)ethen­yl]amine

Beliaev, N.; Slepukhin, P.

doi:10.1107/S2414314615024888

Crystal structure of dimethyl[(E)-2-(1-methyl-5-nitro-1H-imidazol-4-yl)ethenyl]amine

The title compound, C₈H₁₂N₄O₂, crystallized with two independent molecules in the asymmetric unit. The bonds lengths of the enamine moiety show strong conjugation in the N—C=C system. In the crystal, the two independent molecules are linked by C—H

O hydrogen bonds, forming zigzag chains along [10-1]. The chains are linked by further C—H

O hydrogen bonds, forming layers parallel to the ac plane.

Keywords: crystal structure; enamine; imidazole; layered structure; C-H

O hydrogen bonding.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S2414314615024888/su5263sup1.cif Contains datablocks I, Global
	Structure factor file (CIF format) https://doi.org/10.1107/S2414314615024888/su5263Isup2.hkl Contains datablock I
	Chemical Markup Language (CML) file https://doi.org/10.1107/S2414314615024888/su5263Isup3.cml Supplementary material

CCDC reference: 1444628

checkCIF report

Key indicators

Single-crystal X-ray study
T = 295 K
Mean (C-C) = 0.003 Å
R factor = 0.038
wR factor = 0.066
Data-to-parameter ratio = 13.6

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT026_ALERT_3_B Ratio Observed / Unique Reflections (too) Low ..         39 %
PLAT230_ALERT_2_B Hirshfeld Test Diff for    N3     --  C2      ..        7.7 s.u.

Alert level C
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N4     --  C5      ..        6.5 s.u.
PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      7.773 Check
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         16 Report

Alert level G
PLAT005_ALERT_5_G No Embedded Refinement Details found in the CIF      Please Do !
PLAT380_ALERT_4_G Incorrectly? Oriented X(sp2)-Methyl Moiety .....         C7 Check
PLAT380_ALERT_4_G Incorrectly? Oriented X(sp2)-Methyl Moiety .....        C6A Check
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          9 Note
PLAT899_ALERT_4_G SHELXL97   is Deprecated and Succeeded by SHELXL       2014 Note
PLAT910_ALERT_3_G Missing # of FCF Reflection(s) Below Th(Min) ...          4 Report
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600         10 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   2 ALERT level B = A potentially serious problem, consider carefully
   3 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   7 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   5 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

Experimental top

The title compound was synthesized from 1,4-dimethyl-5-nitro-1H-imidazole following a reported procedure (Hosmane et al., 1985), illustrated in Fig. 3, and crystallized from ethanol yielding red prismatic crystals.

Structure description top

The title enamine was synthesized for the study of the [3 + 2] cycloaddition reactions with azides (Bakulev et al., 2012) and hydroxamoylchlorides (Bakulev et al., 2013). It crystallized with two independent molecules in the asymmetric unit, Fig. 1. Both molecules are relatively planar. The mean plane of the N,N-dimethylethenamine group N2/C3/C6–C8 is inclined to the imidazole ring N1/N3/C1/C4/C5 by 2.16 (11)°, while the mean plane of the N,N-dimethylethenamine group N2A/C3A/C6A–C8A is inclined to the imidazole ring NA1/N3A/C1A/C4A/C5A by 6.17 (12)°. The NO₂ group is inclined to the imidazole ring by 8.2 (2)° for ring N1/N3/C1/C4/C5 vs. N4/O1/O2, and 5.0 (2)° for ring N1A/N3A/C1A/C4A/C5A versus. N4A/O1A/O2A. The substituents at the C3═C8 and C3A═C8A bonds are placed in trans-positions. The bonds lengths of the enamine moiety show strong conjugation in the N—C=C system. The N—C bond lengths and C═C bond lengths in the two molecules are very similar: N2—C8 is 1.326 (2) and N2A—C8A 1.331 (2) Å, and C8═C3 is 1.342 (3) and C8A═C3A is 1.334 (2) Å.

In the crystal, the two independent molecules are linked by C—H···O hydrogen bonds, forming zigzag chains along [101]. The chains are linked by further C—H···O hydrogen bonds, forming layers parallel to the ac plane; see Fig. 2 and Table 1.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis CCD (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

	Fig. 1. A view of the molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. A view along the c axis of the crystal packing of the title compound. Hydrogen bonds are drawn as dashed lines (see Table 1), and H atoms not involved in these interactions have been omitted for clarity.
	Fig. 3. Reaction scheme.

Dimethyl[(E)-2-(1-methyl-5-nitro-1H-imidazol-4-yl)ethenyl]amine top

Crystal data top

C₈H₁₂N₄O₂	F(000) = 832
M_r = 196.22	D_x = 1.368 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1523 reflections
a = 10.5015 (12) Å	θ = 2.8–26.4°
b = 23.561 (3) Å	µ = 0.10 mm⁻¹
c = 7.7533 (6) Å	T = 295 K
β = 96.604 (8)°	Prism, red
V = 1905.6 (3) Å³	0.25 × 0.20 × 0.15 mm
Z = 8

Data collection top

Oxford Diffraction Xcalibur S CCD diffractometer	1523 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.038
Graphite monochromator	θ_max = 26.4°, θ_min = 2.8°
ω scans	h = −13→13
10647 measured reflections	k = −28→29
3875 independent reflections	l = −9→6

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.038	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.066	w = 1/[σ²(F_o²) + (0.016P)²] where P = (F_o² + 2F_c²)/3
S = 1.00	(Δ/σ)_max < 0.001
3875 reflections	Δρ_max = 0.14 e Å⁻³
284 parameters	Δρ_min = −0.12 e Å⁻³
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00217 (15)

Crystal data top

C₈H₁₂N₄O₂	V = 1905.6 (3) Å³
M_r = 196.22	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 10.5015 (12) Å	µ = 0.10 mm⁻¹
b = 23.561 (3) Å	T = 295 K
c = 7.7533 (6) Å	0.25 × 0.20 × 0.15 mm
β = 96.604 (8)°

Data collection top

Oxford Diffraction Xcalibur S CCD diffractometer	1523 reflections with I > 2σ(I)
10647 measured reflections	R_int = 0.038
3875 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.038	0 restraints
wR(F²) = 0.066	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	Δρ_max = 0.14 e Å⁻³
3875 reflections	Δρ_min = −0.12 e Å⁻³
284 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.

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
N1	0.44977 (16)	0.40312 (6)	0.2065 (2)	0.0497 (5)
N1A	1.04292 (17)	−0.01495 (7)	0.7905 (2)	0.0531 (5)
O1A	0.80215 (14)	−0.03162 (6)	0.6211 (2)	0.0983 (6)
C1A	1.02942 (19)	−0.07638 (7)	0.7864 (2)	0.0718 (6)
H1AA	1.1008	−0.0933	0.8564	0.108*
H1AB	1.0273	−0.0895	0.6689	0.108*
H1AC	0.9512	−0.0869	0.8312	0.108*
O2A	0.78287 (14)	0.05713 (6)	0.56123 (18)	0.0818 (5)
N2A	1.02826 (16)	0.23407 (8)	0.7367 (2)	0.0608 (5)
C2A	1.1448 (2)	0.01246 (9)	0.8654 (3)	0.0615 (6)
N3A	1.14002 (15)	0.06755 (7)	0.8499 (2)	0.0587 (5)
C3A	0.9826 (2)	0.13453 (8)	0.7150 (3)	0.0510 (6)
C4A	1.02459 (18)	0.07855 (7)	0.7556 (2)	0.0454 (5)
N4A	0.84503 (18)	0.01685 (7)	0.6297 (2)	0.0619 (5)
C5A	0.96365 (19)	0.02736 (8)	0.7181 (2)	0.0471 (5)
C6A	1.12128 (19)	0.27801 (8)	0.7863 (3)	0.0796 (7)
H6AA	1.1992	0.2611	0.8394	0.119*
H6AB	1.0881	0.3033	0.8672	0.119*
H6AC	1.1384	0.2988	0.6850	0.119*
C7A	0.9047 (2)	0.25138 (8)	0.6542 (3)	0.0795 (8)
H7AA	0.8388	0.2348	0.7140	0.119*
H7AB	0.8947	0.2389	0.5355	0.119*
H7AC	0.8981	0.2920	0.6580	0.119*
C8A	1.0565 (2)	0.17934 (9)	0.7605 (3)	0.0511 (6)
O1	0.66579 (13)	0.42352 (6)	0.43092 (17)	0.0828 (5)
C1	0.46003 (19)	0.46466 (8)	0.2120 (2)	0.0690 (7)
H1A	0.3908	0.4810	0.1365	0.104*
H1B	0.5402	0.4760	0.1745	0.104*
H1C	0.4559	0.4776	0.3286	0.104*
O2	0.71826 (12)	0.33445 (6)	0.43022 (17)	0.0716 (4)
N2	0.49194 (15)	0.15456 (7)	0.21675 (19)	0.0565 (5)
C2	0.3544 (2)	0.37399 (10)	0.1211 (3)	0.0557 (6)
N3	0.36672 (15)	0.31899 (7)	0.12659 (19)	0.0540 (5)
C3	0.5290 (2)	0.25429 (8)	0.2591 (3)	0.0490 (6)
C4	0.48305 (17)	0.30967 (7)	0.2234 (2)	0.0436 (5)
N4	0.64519 (17)	0.37394 (7)	0.3824 (2)	0.0553 (5)
C5	0.53483 (19)	0.36189 (8)	0.2743 (2)	0.0440 (5)
C6	0.4020 (2)	0.11081 (8)	0.1539 (3)	0.0760 (7)
H6A	0.3369	0.1268	0.0710	0.114*
H6B	0.3630	0.0952	0.2495	0.114*
H6C	0.4463	0.0813	0.0995	0.114*
C7	0.60698 (19)	0.13755 (8)	0.3232 (2)	0.0726 (7)
H7A	0.6803	0.1529	0.2759	0.109*
H7B	0.6125	0.0969	0.3254	0.109*
H7C	0.6049	0.1515	0.4391	0.109*
C8	0.4624 (2)	0.20899 (9)	0.1940 (3)	0.0494 (6)
H2	0.2798 (15)	0.3923 (6)	0.0652 (19)	0.048 (5)*
H2A	1.2150 (16)	−0.0078 (6)	0.927 (2)	0.064 (6)*
H8A	1.1417 (15)	0.1740 (6)	0.8116 (19)	0.057 (6)*
H3A	0.9011 (15)	0.1399 (6)	0.6555 (19)	0.054 (6)*
H8	0.3814 (15)	0.2149 (6)	0.1173 (19)	0.049 (5)*
H3	0.6049 (15)	0.2509 (6)	0.3238 (19)	0.053 (6)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0538 (11)	0.0434 (11)	0.0506 (11)	0.0017 (10)	0.0003 (9)	0.0025 (9)
N1A	0.0560 (12)	0.0434 (11)	0.0594 (12)	0.0008 (10)	0.0038 (10)	0.0030 (9)
O1A	0.0962 (13)	0.0684 (10)	0.1209 (14)	−0.0340 (9)	−0.0282 (10)	0.0003 (10)
C1A	0.0934 (17)	0.0440 (14)	0.0788 (16)	−0.0007 (12)	0.0138 (13)	0.0044 (13)
O2A	0.0665 (10)	0.0818 (11)	0.0895 (12)	−0.0025 (9)	−0.0231 (9)	0.0131 (9)
N2A	0.0581 (13)	0.0494 (12)	0.0741 (13)	0.0052 (10)	0.0046 (11)	0.0024 (10)
C2A	0.0515 (15)	0.0555 (16)	0.0745 (17)	0.0045 (13)	−0.0050 (13)	0.0077 (14)
N3A	0.0482 (11)	0.0517 (11)	0.0727 (12)	0.0015 (9)	−0.0082 (9)	0.0051 (10)
C3A	0.0460 (16)	0.0481 (15)	0.0568 (15)	0.0001 (12)	−0.0038 (13)	0.0024 (11)
C4A	0.0420 (13)	0.0476 (13)	0.0464 (13)	−0.0023 (11)	0.0045 (11)	0.0032 (11)
N4A	0.0610 (14)	0.0622 (13)	0.0594 (13)	−0.0089 (11)	−0.0062 (11)	0.0008 (11)
C5A	0.0440 (13)	0.0477 (14)	0.0483 (14)	−0.0026 (12)	−0.0003 (11)	0.0006 (11)
C6A	0.0816 (17)	0.0568 (15)	0.1014 (18)	−0.0096 (13)	0.0145 (15)	−0.0051 (13)
C7A	0.0725 (18)	0.0775 (18)	0.0875 (17)	0.0255 (13)	0.0043 (15)	0.0161 (13)
C8A	0.0484 (15)	0.0473 (15)	0.0570 (15)	0.0094 (12)	0.0035 (12)	0.0023 (12)
O1	0.0893 (12)	0.0601 (9)	0.0920 (12)	−0.0178 (8)	−0.0203 (9)	−0.0156 (9)
C1	0.0809 (16)	0.0462 (14)	0.0779 (16)	0.0007 (11)	0.0001 (13)	0.0059 (12)
O2	0.0562 (9)	0.0739 (10)	0.0796 (10)	0.0090 (8)	−0.0139 (8)	−0.0015 (8)
N2	0.0629 (12)	0.0424 (12)	0.0633 (12)	0.0028 (9)	0.0032 (10)	0.0003 (10)
C2	0.0483 (15)	0.0629 (16)	0.0535 (15)	0.0034 (13)	−0.0048 (12)	0.0048 (13)
N3	0.0531 (11)	0.0482 (11)	0.0583 (11)	0.0049 (8)	−0.0036 (9)	0.0007 (9)
C3	0.0437 (15)	0.0555 (16)	0.0470 (14)	0.0015 (12)	0.0013 (12)	−0.0002 (12)
C4	0.0455 (14)	0.0485 (13)	0.0363 (12)	0.0022 (11)	0.0030 (10)	0.0028 (11)
N4	0.0538 (12)	0.0571 (13)	0.0534 (12)	−0.0025 (10)	0.0000 (10)	−0.0006 (10)
C5	0.0425 (13)	0.0466 (14)	0.0413 (13)	−0.0020 (11)	−0.0014 (11)	−0.0022 (11)
C6	0.0903 (18)	0.0578 (15)	0.0823 (16)	−0.0160 (13)	0.0199 (15)	−0.0092 (13)
C7	0.0865 (18)	0.0634 (16)	0.0663 (15)	0.0184 (12)	0.0015 (14)	0.0055 (12)
C8	0.0527 (15)	0.0493 (15)	0.0463 (14)	0.0022 (12)	0.0061 (12)	−0.0010 (11)

Geometric parameters (Å, º) top

N1—C2	1.327 (2)	C7A—H7AB	0.9600
N1—C5	1.382 (2)	C7A—H7AC	0.9600
N1—C1	1.4543 (19)	C8A—H8A	0.944 (14)
N1A—C2A	1.325 (2)	O1—N4	1.2387 (17)
N1A—C5A	1.376 (2)	C1—H1A	0.9600
N1A—C1A	1.4544 (19)	C1—H1B	0.9600
O1A—N4A	1.2264 (17)	C1—H1C	0.9600
C1A—H1AA	0.9600	O2—N4	1.2355 (17)
C1A—H1AB	0.9600	N2—C8	1.326 (2)
C1A—H1AC	0.9600	N2—C7	1.4393 (19)
O2A—N4A	1.2365 (17)	N2—C6	1.444 (2)
N2A—C8A	1.331 (2)	C2—N3	1.303 (2)
N2A—C7A	1.438 (2)	C2—H2	0.954 (14)
N2A—C6A	1.445 (2)	N3—C4	1.3760 (19)
C2A—N3A	1.304 (2)	C3—C8	1.342 (2)
C2A—H2A	0.959 (15)	C3—C4	1.408 (2)
N3A—C4A	1.3665 (19)	C3—H3	0.895 (14)
C3A—C8A	1.334 (2)	C4—C5	1.384 (2)
C3A—C4A	1.415 (2)	N4—C5	1.379 (2)
C3A—H3A	0.933 (14)	C6—H6A	0.9600
C4A—C5A	1.380 (2)	C6—H6B	0.9600
N4A—C5A	1.374 (2)	C6—H6C	0.9600
C6A—H6AA	0.9600	C7—H7A	0.9600
C6A—H6AB	0.9600	C7—H7B	0.9600
C6A—H6AC	0.9600	C7—H7C	0.9600
C7A—H7AA	0.9600	C8—H8	0.990 (14)

C2—N1—C5	104.14 (17)	N2A—C8A—C3A	128.1 (2)
C2—N1—C1	125.41 (17)	N2A—C8A—H8A	111.9 (9)
C5—N1—C1	130.33 (17)	C3A—C8A—H8A	120.0 (9)
C2A—N1A—C5A	104.22 (18)	N1—C1—H1A	109.5
C2A—N1A—C1A	124.50 (17)	N1—C1—H1B	109.5
C5A—N1A—C1A	131.23 (18)	H1A—C1—H1B	109.5
N1A—C1A—H1AA	109.5	N1—C1—H1C	109.5
N1A—C1A—H1AB	109.5	H1A—C1—H1C	109.5
H1AA—C1A—H1AB	109.5	H1B—C1—H1C	109.5
N1A—C1A—H1AC	109.5	C8—N2—C7	120.89 (17)
H1AA—C1A—H1AC	109.5	C8—N2—C6	120.77 (17)
H1AB—C1A—H1AC	109.5	C7—N2—C6	117.89 (17)
C8A—N2A—C7A	120.78 (18)	N3—C2—N1	115.58 (19)
C8A—N2A—C6A	121.61 (18)	N3—C2—H2	122.6 (9)
C7A—N2A—C6A	117.57 (18)	N1—C2—H2	121.8 (9)
N3A—C2A—N1A	115.10 (19)	C2—N3—C4	104.80 (16)
N3A—C2A—H2A	124.1 (10)	C8—C3—C4	120.7 (2)
N1A—C2A—H2A	120.8 (10)	C8—C3—H3	122.0 (10)
C2A—N3A—C4A	105.09 (16)	C4—C3—H3	117.2 (10)
C8A—C3A—C4A	121.5 (2)	N3—C4—C5	107.98 (15)
C8A—C3A—H3A	119.8 (9)	N3—C4—C3	121.21 (17)
C4A—C3A—H3A	118.7 (9)	C5—C4—C3	130.78 (17)
N3A—C4A—C5A	107.95 (15)	O2—N4—O1	122.57 (17)
N3A—C4A—C3A	122.03 (17)	O2—N4—C5	118.48 (17)
C5A—C4A—C3A	130.00 (18)	O1—N4—C5	118.93 (17)
O1A—N4A—O2A	121.28 (18)	N4—C5—N1	123.21 (17)
O1A—N4A—C5A	120.07 (17)	N4—C5—C4	129.14 (18)
O2A—N4A—C5A	118.65 (17)	N1—C5—C4	107.50 (16)
N4A—C5A—N1A	122.98 (18)	N2—C6—H6A	109.5
N4A—C5A—C4A	129.37 (18)	N2—C6—H6B	109.5
N1A—C5A—C4A	107.64 (16)	H6A—C6—H6B	109.5
N2A—C6A—H6AA	109.5	N2—C6—H6C	109.5
N2A—C6A—H6AB	109.5	H6A—C6—H6C	109.5
H6AA—C6A—H6AB	109.5	H6B—C6—H6C	109.5
N2A—C6A—H6AC	109.5	N2—C7—H7A	109.5
H6AA—C6A—H6AC	109.5	N2—C7—H7B	109.5
H6AB—C6A—H6AC	109.5	H7A—C7—H7B	109.5
N2A—C7A—H7AA	109.5	N2—C7—H7C	109.5
N2A—C7A—H7AB	109.5	H7A—C7—H7C	109.5
H7AA—C7A—H7AB	109.5	H7B—C7—H7C	109.5
N2A—C7A—H7AC	109.5	N2—C8—C3	128.0 (2)
H7AA—C7A—H7AC	109.5	N2—C8—H8	112.8 (8)
H7AB—C7A—H7AC	109.5	C3—C8—H8	119.3 (8)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···O1Aⁱ	0.954 (15)	2.399 (15)	3.235 (3)	146 (1)
C2A—H2A···O1ⁱⁱ	0.958 (16)	2.254 (15)	3.181 (3)	162 (1)
C6—H6B···O1Aⁱⁱⁱ	0.96	2.58	3.461 (3)	153

Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x+2, y−1/2, −z+3/2; (iii) −x+1, −y, −z+1.