4,6-Di­methyl-2-(o-tolyl­imino­methyl)­quinoline

The molecule of the title compound, C₁₉H₁₈N₂, is not planar. The dihedral angle between the quinoline and phenyl rings is 118.5 (1)°.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.073
• wR factor = 0.187
• Data-to-parameter ratio = 17.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



PLAT_030  Alert C Refined Extinction parameter within range ....       2.56 Sigma

General Notes



GOODF_01  _refine_ls_goodness_of_fit_obs is an old dataname which has
          been superseded by _refine_ls_goodness_of_fit_ref

REFLE_01  _reflns_observed_criterion is an old dataname which has been
          superseded by _reflns_threshold_expression

REFLG_01  _reflns_number_observed is an old dataname which has been
          superseded by _reflns_number_gt

RFACG_01  _refine_ls_R_factor_obs is an old dataname which has been
          superseded by _refine_ls_R_factor_gt

RFACR_01  _refine_ls_wR_factor_obs is an old dataname which has been
          superseded by _refine_ls_wR_factor_ref

SHFSU_01  _refine_ls_shift/esd_max is an old dataname which has been
          superseded by _refine_ls_shift/su_max


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 1 Alert Level C = Please check

---

S1. Comment

Interest in quinoxaline derivatives has increased greatly during recent years due to their different applications in various areas. Some derivatives are used as colorimetric agents (Campaigne & McLaughlin, 1983), antibacterial agents (Boutti & Lecolier,1976) and colouring matter. Other derivatives possess various biological activities (De Clercq, 1998; Li et al., 1997). Much attention has recently begun to concentrate on compounds obtained from heterocyclic carbaldehydes for the treatment of cancer (Kouznetsov et al., 1998; Öcal & Kaban, 1998). The structure of 4,6-Dimethyl-2-(o-tolyliminomethyl)quinoline, (I), has beed determined and is presented here.

The quinoline and phenyl rings are planar. In the quinoline ring, the angle C3—C4—C5 is greater than 120° [123.4 (2)°] and the angle C8—C9—N1 is smaller than 120° [118.2 (2)°] (Öztürk et al., 2000). The dihedral angle between the least-squares planes of the quinoline and phenyl rings is 118.5 (1)°.

S2. Experimental

The title compound was synthesized by the condensation of 4,6-dimethylquinoline-2-carbaldehyde with o-toluidine in dry ethanol for 6.5 h. Light-yellow crystals were obtained after crystallization from ethanol. Yield: 54%; m.p.: 392 K; IR (KBr): γ 3040, 2890, 1585 cm^-1; ¹H NMR (CDCl₃, δ, 200 MHz): 2.46 (3H, s, o-CH₃), 2.59 (3H, s, 6-CH₃), 2.76 (3H, s, 4-CH₃), 7.05–8.64 (9H, m, ArH and CH) p.p.m.; UV (CHCl₃): λ_max 260.8, 312.5 nm. Elemental analysis, C₁₉H₁₈N₂ requires: C 83.18, H 6.61, N 10.21%; found: C 83.14, H 6.58, N 10.11% (Aydo~gan, 1993).

S3. Refinement

The methyl groups were allowed to rotate about their local threefold axes.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL93 (Sheldrick, 1993); molecular graphics: ORTEPII (Johnson, 1976).

Figures

Fig. 1. An ORTEPII drawing of the molecular structure of (I) showing the labelling of the non-H atoms. Anisotropic displacement ellipsoids are shown at the 50% probability level.

4,6-Dimethyl-2-(o-tolyliminomethyl)quinoline

Crystal data

C19H18N2	Z = 2
Mr = 274.37	F(000) = 294
Triclinic, P1	Dx = 1.180 Mg m^−3
a = 7.5693 (7) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.5620 (9) Å	Cell parameters from 1739 reflections
c = 11.3908 (11) Å	θ = 3.1–27.5°
α = 79.203 (2)°	µ = 0.07 mm^−1
β = 76.735 (2)°	T = 293 K
γ = 77.514 (2)°	Needle, colourless
V = 775.19 (13) Å^3	0.44 × 0.26 × 0.06 mm

Data collection

Siemens SMART 1000 CCD area-detector diffractometer	1697 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.035
Graphite monochromator	θmax = 27.5°, θmin = 3.1°
ω scans	h = −9→9
5000 measured reflections	k = −12→12
3414 independent reflections	l = −14→14

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.073	H-atom parameters constrained
wR(F^2) = 0.236	w = 1/[σ^2(Fo^2) + (0.1124P)^2 + 0.041P] where P = (Fo^2 + 2Fc^2)/3
S = 1.02	(Δ/σ)max < 0.001
3414 reflections	Δρmax = 0.24 e Å^−3
194 parameters	Δρmin = −0.27 e Å^−3
0 restraints	Extinction correction: SHELXL93, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.023 (9)

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 on F² for ALL reflections except for 0 with very negative F² or flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating R-factor-obs 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 (Ų)

	x	y	z	Uiso*/Ueq
N1	0.2160 (3)	0.1467 (2)	0.2710 (2)	0.0529 (6)
N2	0.2614 (3)	0.5139 (2)	0.2097 (2)	0.0544 (6)
C1	0.2282 (4)	0.2707 (3)	0.2999 (2)	0.0504 (7)
C2	0.2442 (4)	0.2870 (3)	0.4167 (2)	0.0531 (7)
H2B	0.2493	0.3779	0.4326	0.064*
C3	0.2524 (4)	0.1713 (3)	0.5074 (2)	0.0504 (7)
C4	0.2448 (3)	0.0344 (3)	0.4775 (2)	0.0463 (6)
C5	0.2588 (4)	−0.0961 (3)	0.5607 (3)	0.0566 (7)
H5A	0.2738	−0.0940	0.6391	0.068*
C6	0.2507 (4)	−0.2254 (3)	0.5284 (3)	0.0604 (8)
C7	0.2279 (4)	−0.2278 (3)	0.4103 (3)	0.0641 (8)
H7A	0.2215	−0.3151	0.3882	0.077*
C8	0.2148 (4)	−0.1058 (3)	0.3274 (3)	0.0594 (8)
H8A	0.1982	−0.1103	0.2499	0.071*
C9	0.2263 (4)	0.0276 (3)	0.3581 (2)	0.0494 (7)
C10	0.2665 (5)	0.1883 (3)	0.6327 (3)	0.0649 (9)
H10A	0.3793	0.1303	0.6522	0.097*
H10B	0.1635	0.1573	0.6907	0.097*
H10C	0.2657	0.2881	0.6356	0.097*
C11	0.2706 (5)	−0.3633 (3)	0.6187 (4)	0.0832 (11)
H11A	0.1772	−0.4169	0.6183	0.125*
H11B	0.2569	−0.3394	0.6989	0.125*
H11C	0.3903	−0.4209	0.5961	0.125*
C12	0.2241 (4)	0.3936 (3)	0.2010 (3)	0.0556 (7)
H12A	0.1930	0.3828	0.1293	0.067*
C13	0.2501 (4)	0.6284 (3)	0.1108 (2)	0.0514 (7)
C14	0.0932 (5)	0.6723 (3)	0.0603 (3)	0.0696 (9)
H14A	−0.0047	0.6224	0.0885	0.083*
C15	0.0804 (6)	0.7884 (4)	−0.0307 (3)	0.0859 (11)
H15A	−0.0250	0.8171	−0.0642	0.103*
C16	0.2257 (6)	0.8616 (4)	−0.0716 (3)	0.0853 (12)
H16A	0.2185	0.9401	−0.1334	0.102*
C17	0.3818 (5)	0.8196 (3)	−0.0218 (3)	0.0724 (9)
H17A	0.4786	0.8705	−0.0504	0.087*
C18	0.3972 (4)	0.7027 (3)	0.0705 (2)	0.0549 (7)
C19	0.5668 (5)	0.6568 (4)	0.1253 (3)	0.0773 (10)
H19A	0.6451	0.7278	0.0960	0.116*
H19B	0.6322	0.5650	0.1024	0.116*
H19C	0.5317	0.6483	0.2125	0.116*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.061 (2)	0.0579 (14)	0.0441 (12)	−0.0158 (11)	−0.0143 (10)	−0.0078 (11)
N2	0.061 (2)	0.0510 (13)	0.0520 (13)	−0.0140 (11)	−0.0165 (11)	0.0016 (11)
C1	0.052 (2)	0.049 (2)	0.053 (2)	−0.0121 (12)	−0.0143 (13)	−0.0062 (13)
C2	0.062 (2)	0.0454 (15)	0.057 (2)	−0.0178 (13)	−0.0171 (13)	−0.0053 (14)
C3	0.052 (2)	0.051 (2)	0.052 (2)	−0.0145 (12)	−0.0133 (12)	−0.0064 (13)
C4	0.0426 (15)	0.0440 (14)	0.053 (2)	−0.0101 (11)	−0.0101 (12)	−0.0041 (13)
C5	0.059 (2)	0.050 (2)	0.059 (2)	−0.0092 (13)	−0.0149 (14)	0.0000 (14)
C6	0.056 (2)	0.045 (2)	0.075 (2)	−0.0076 (13)	−0.0081 (15)	−0.0040 (15)
C7	0.065 (2)	0.045 (2)	0.085 (2)	−0.0112 (14)	−0.011 (2)	−0.017 (2)
C8	0.061 (2)	0.057 (2)	0.064 (2)	−0.0143 (14)	−0.0119 (14)	−0.017 (2)
C9	0.046 (2)	0.0477 (15)	0.056 (2)	−0.0100 (12)	−0.0100 (12)	−0.0080 (13)
C10	0.088 (2)	0.057 (2)	0.056 (2)	−0.021 (2)	−0.024 (2)	−0.0058 (15)
C11	0.086 (3)	0.050 (2)	0.105 (3)	−0.010 (2)	−0.017 (2)	0.005 (2)
C12	0.063 (2)	0.058 (2)	0.049 (2)	−0.0120 (14)	−0.0172 (13)	−0.0045 (14)
C13	0.064 (2)	0.0474 (15)	0.0455 (15)	−0.0115 (13)	−0.0170 (13)	−0.0036 (13)
C14	0.074 (2)	0.066 (2)	0.074 (2)	−0.017 (2)	−0.031 (2)	0.002 (2)
C15	0.100 (3)	0.074 (2)	0.087 (2)	−0.007 (2)	−0.050 (2)	0.009 (2)
C16	0.126 (3)	0.062 (2)	0.061 (2)	−0.013 (2)	−0.028 (2)	0.014 (2)
C17	0.094 (3)	0.064 (2)	0.057 (2)	−0.026 (2)	−0.007 (2)	−0.001 (2)
C18	0.067 (2)	0.053 (2)	0.0457 (15)	−0.0158 (14)	−0.0092 (13)	−0.0050 (13)
C19	0.068 (2)	0.093 (2)	0.074 (2)	−0.025 (2)	−0.016 (2)	−0.006 (2)

Geometric parameters (Å, º)

N1—C1	1.316 (3)	C10—H10B	0.96
N1—C9	1.364 (3)	C10—H10C	0.96
N2—C12	1.267 (3)	C11—H11A	0.96
N2—C13	1.420 (3)	C11—H11B	0.96
C1—C2	1.403 (4)	C11—H11C	0.96
C1—C12	1.468 (4)	C12—H12A	0.93
C2—C3	1.366 (3)	C13—C14	1.388 (4)
C2—H2B	0.93	C13—C18	1.393 (4)
C3—C4	1.429 (3)	C14—C15	1.373 (4)
C3—C10	1.496 (4)	C14—H14A	0.93
C4—C9	1.413 (4)	C15—C16	1.376 (5)
C4—C5	1.419 (3)	C15—H15A	0.93
C5—C6	1.371 (4)	C16—C17	1.377 (5)
C5—H5A	0.93	C16—H16A	0.93
C6—C7	1.400 (4)	C17—C18	1.388 (4)
C6—C11	1.515 (4)	C17—H17A	0.93
C7—C8	1.357 (4)	C18—C19	1.501 (4)
C7—H7A	0.93	C19—H19A	0.96
C8—C9	1.410 (4)	C19—H19B	0.96
C8—H8A	0.93	C19—H19C	0.96
C10—H10A	0.96
C1—N1—C9	118.0 (2)	H10B—C10—H10C	109.5
C12—N2—C13	119.0 (2)	C6—C11—H11A	109.5 (2)
N1—C1—C2	123.2 (3)	C6—C11—H11B	109.5 (2)
N1—C1—C12	115.5 (2)	H11A—C11—H11B	109.5
C2—C1—C12	121.3 (2)	C6—C11—H11C	109.5 (2)
C3—C2—C1	120.9 (2)	H11A—C11—H11C	109.5
C3—C2—H2B	119.6 (2)	H11B—C11—H11C	109.5
C1—C2—H2B	119.6 (2)	N2—C12—C1	122.5 (3)
C2—C3—C4	117.0 (2)	N2—C12—H12A	118.7 (2)
C2—C3—C10	121.2 (2)	C1—C12—H12A	118.7 (2)
C4—C3—C10	121.8 (2)	C14—C13—C18	120.3 (3)
C9—C4—C5	118.1 (2)	C14—C13—N2	121.6 (3)
C9—C4—C3	118.5 (2)	C18—C13—N2	118.0 (2)
C5—C4—C3	123.4 (2)	C15—C14—C13	120.8 (3)
C6—C5—C4	121.6 (3)	C15—C14—H14A	119.6 (2)
C6—C5—H5A	119.2 (2)	C13—C14—H14A	119.6 (2)
C4—C5—H5A	119.2 (2)	C14—C15—C16	119.1 (3)
C5—C6—C7	118.9 (3)	C14—C15—H15A	120.4 (2)
C5—C6—C11	120.2 (3)	C16—C15—H15A	120.4 (2)
C7—C6—C11	120.9 (3)	C15—C16—C17	120.6 (3)
C8—C7—C6	121.6 (3)	C15—C16—H16A	119.7 (2)
C8—C7—H7A	119.2 (2)	C17—C16—H16A	119.7 (2)
C6—C7—H7A	119.2 (2)	C16—C17—C18	121.2 (3)
C7—C8—C9	120.3 (3)	C16—C17—H17A	119.4 (2)
C7—C8—H8A	119.8 (2)	C18—C17—H17A	119.4 (2)
C9—C8—H8A	119.8 (2)	C17—C18—C13	117.9 (3)
N1—C9—C8	118.2 (2)	C17—C18—C19	121.3 (3)
N1—C9—C4	122.3 (2)	C13—C18—C19	120.7 (3)
C8—C9—C4	119.5 (3)	C18—C19—H19A	109.5 (2)
C3—C10—H10A	109.5 (2)	C18—C19—H19B	109.5 (2)
C3—C10—H10B	109.5 (2)	H19A—C19—H19B	109.5
H10A—C10—H10B	109.5	C18—C19—H19C	109.5 (2)
C3—C10—H10C	109.5 (2)	H19A—C19—H19C	109.5
H10A—C10—H10C	109.5	H19B—C19—H19C	109.5
C9—N1—C1—C2	−2.5 (4)	C5—C4—C9—N1	−178.5 (2)
C9—N1—C1—C12	177.5 (2)	C3—C4—C9—N1	0.2 (4)
N1—C1—C2—C3	1.6 (4)	C5—C4—C9—C8	2.6 (4)
C12—C1—C2—C3	−178.4 (3)	C3—C4—C9—C8	−178.7 (2)
C1—C2—C3—C4	0.3 (4)	C13—N2—C12—C1	−178.6 (2)
C1—C2—C3—C10	−179.1 (3)	N1—C1—C12—N2	−169.4 (3)
C2—C3—C4—C9	−1.1 (4)	C2—C1—C12—N2	10.6 (4)
C10—C3—C4—C9	178.3 (3)	C12—N2—C13—C14	52.1 (4)
C2—C3—C4—C5	177.5 (3)	C12—N2—C13—C18	−132.1 (3)
C10—C3—C4—C5	−3.1 (4)	C18—C13—C14—C15	0.6 (5)
C9—C4—C5—C6	−1.4 (4)	N2—C13—C14—C15	176.3 (3)
C3—C4—C5—C6	179.9 (3)	C13—C14—C15—C16	−0.1 (5)
C4—C5—C6—C7	−0.1 (4)	C14—C15—C16—C17	−0.3 (5)
C4—C5—C6—C11	178.5 (3)	C15—C16—C17—C18	0.2 (5)
C5—C6—C7—C8	0.4 (5)	C16—C17—C18—C13	0.3 (4)
C11—C6—C7—C8	−178.2 (3)	C16—C17—C18—C19	−179.8 (3)
C6—C7—C8—C9	0.8 (5)	C14—C13—C18—C17	−0.7 (4)
C1—N1—C9—C8	−179.5 (2)	N2—C13—C18—C17	−176.6 (3)
C1—N1—C9—C4	1.6 (4)	C14—C13—C18—C19	179.4 (3)
C7—C8—C9—N1	178.7 (3)	N2—C13—C18—C19	3.6 (4)
C7—C8—C9—C4	−2.3 (4)