Crystal structure of 1-(2,4-di­methyl­phen­yl)urea

In the title urea derivative, C₉H₁₂N₂O, the dihedral angle between the benzene ring and the mean plane of the urea group, N—C(=O)—N, is 86.6 (1)°. In the crystal, the urea O atom is involved in three N—H...O hydrogen bonds. Mol­ecules are linked via pairs of N—H...O hydrogen bonds, forming inversion dimers with an R²₂(8) ring motif. The dimers are linked by further N—H...O hydrogen bonds, forming two-dimensional networks lying parallel to (100).

Key indicators

• Single-crystal X-ray study
• T = 292 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.100
• wR factor = 0.349
• Data-to-parameter ratio = 13.1

checkCIF/PLATON results

No syntax errors found



Alert level B
DIFMX01_ALERT_2_B  The maximum difference density is > 0.1*ZMAX*1.00
            _refine_diff_density_max given =      0.868
            Test value =      0.800
PLAT019_ALERT_1_B  _diffrn_measured_fraction_theta_full/_max < 1.0      0.978 Report
PLAT097_ALERT_2_B Large Reported Max.  (Positive) Residual Density       0.87 eA-3
PLAT230_ALERT_2_B Hirshfeld Test Diff for    C1     --  C2      ..        8.2 su

Alert level C
DIFMX02_ALERT_1_C  The maximum difference density is > 0.1*ZMAX*0.75
            The relevant atom site should be identified.
RFACR01_ALERT_3_C  The value of the weighted R factor is > 0.25
            Weighted R factor given   0.349
PLAT084_ALERT_3_C High wR2 Value (i.e. > 0.25) ...................       0.35 Report
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.73 Report
PLAT220_ALERT_2_C Large Non-Solvent  C     Ueq(max)/Ueq(min) Range        3.4 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H    Uiso(max)/Uiso(min) ..        4.4 Ratio
PLAT242_ALERT_2_C Low       Ueq as Compared to Neighbors for .....         C9 Check
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....        2.6 Note
PLAT334_ALERT_2_C Small Average Benzene  C-C Dist. C1     -C6            1.37 Ang.
PLAT340_ALERT_3_C Low Bond Precision on  C-C Bonds ...............     0.0074 Ang.
PLAT362_ALERT_2_C Short  C(sp3)-C(sp2) Bond  C4     -   C8     ...       1.41 Ang.
PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      2.343 Check
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.595         51 Report

Alert level G
PLAT002_ALERT_2_G Number of Distance or Angle Restraints on AtSite          3 Note
PLAT007_ALERT_5_G Number of Unrefined Donor-H Atoms ..............          1 Report
PLAT072_ALERT_2_G SHELXL First  Parameter in WGHT Unusually Large.       0.20 Report
PLAT172_ALERT_4_G The CIF-Embedded .res File Contains DFIX Records          1 Report
PLAT860_ALERT_3_G Number of Least-Squares Restraints .............          2 Note
PLAT909_ALERT_3_G Percentage of Observed Data at Theta(Max) still          62 %
PLAT910_ALERT_3_G Missing # of FCF Reflections Below Th(Min) .....          1 Report

   0 ALERT level A = Most likely a serious problem - resolve or explain
   4 ALERT level B = A potentially serious problem, consider carefully
  13 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

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

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S1. Comment

Urea and its derivatives are important key starting materials for the construction of biologically important heterocycles (Ramalingan & Kwak, 2008; Ramalingan et al., 2010; Yang et al., 2013; Safari & Gandomi-Ravandi, 2014). They display various biological activities viz. antibacterial (Suzuki et al., 2013), antiproliferative and antitumor (Boulahjar et al., 2012), and HIV-1 integrase (Zhang et al., 2014). As a vital reactant and intermediate for the construction of heterocyclic chemical entities of biological importance, the title compound has been synthesized and single crystals were grown by slow evaporation in ethanol.

The single crystal X-ray analysis confirmed the molecular structure, as illustrated in Fig. 1. Methyl carbon atoms, C7 and C8, deviate by -0.000 (1) and -0.040 (1) Å, respectively, from the attached benzene ring. The dihedral angle between benzene ring and the mean plane through the urea atoms (N1/C9/O1/N2) is 86.6 (1)°.

In the crystal, three strong N—H···O hydrogen bonds stabilize the molecular packing (Fig. 2 and Table 1). Molecules are linked via pairs of N-H···O hydrogen bonds forming inversion dimers with an R²₂(8) ring motif. The dimers are linked by further N-H···O hydrogen bonds forming two-dimensional networks lying parallel to (100); see Table 1 and Fig. 2.

Related literature

For general background to urea derivatives and their biological applications and properties, see: Ramalingan & Kwak (2008); Ramalingan et al. (2010); Yang et al. (2013); Safari & Gandomi-Ravandi (2014); Suzuki et al. (2013); Boulahjar et al. (2012); Zhang et al. (2014)

S2. Experimental

To a solution of 2,6-dimethylaniline (0.1 mol) in glacial acetic acid (30 ml), was added distilled water (70 ml). Sodium cyanate (0.1 mol) in medium-hot water (50 ml) was then added in a slow manner with constant stirring. The resulted solution was allowed to stand for 60 min. and then cooled in ice. It was then filtered using a Buchner funnel and the solid obtained was dried using high-vacuum. Single crystals of the title compound were obtained by slow evaporation of a solution in ethanol at room temperature.

S3. Refinement

Atoms H2A and H2B were located from a difference Fourier map and freely refined. The remaining H atoms were positioned geometrically and allowed to ride on their parent atoms, with N—H = 0.86 Å and C—H = 0.93-0.96 Å and with U_iso(H) = 1.5U_eq(C) for methyl H atoms and = 1.2U_eq (N,C) for other H atoms.

Computing details

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: SHELXL2013 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL2013 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures

	Fig. 1. The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. A projection of the crystal packing of the title compound, along the a axis. Hydrogen bonds are shown as dashed lines (see Table 1 for details; H atoms not involved in hydrogen bonding have been omitted for clarity).

1-(2,4-Dimethylphenyl)urea

Crystal data

C9H12N2O	F(000) = 352
Mr = 164.21	Dx = 1.204 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 14.631 (4) Å	Cell parameters from 6568 reflections
b = 7.0633 (19) Å	θ = 2.8–24.6°
c = 8.786 (2) Å	µ = 0.08 mm^−1
β = 93.530 (4)°	T = 292 K
V = 906.2 (4) Å^3	Block, colourless
Z = 4	0.20 × 0.18 × 0.16 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer	Rint = 0.028
Radiation source: fine-focus sealed tube	θmax = 25.0°, θmin = 2.8°
ω scans	h = −17→17
8026 measured reflections	k = −8→8
1556 independent reflections	l = −10→10
1284 reflections with I > 2σ(I)

Refinement

Refinement on F^2	2 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.100	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.349	w = 1/[σ^2(Fo^2) + (0.2P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.59	(Δ/σ)max = 0.001
1556 reflections	Δρmax = 0.87 e Å^−3
119 parameters	Δρmin = −0.32 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
O1	0.40043 (14)	0.1453 (3)	0.55423 (18)	0.0634 (8)
N1	0.32526 (19)	0.2851 (4)	0.3520 (3)	0.0709 (10)
H1	0.3186	0.2927	0.2543	0.085*
N2	0.4476 (2)	0.0982 (4)	0.3174 (3)	0.0682 (9)
H2A	0.437 (2)	0.125 (4)	0.2228 (15)	0.060 (8)*
H2B	0.4934 (19)	0.036 (5)	0.360 (4)	0.089 (11)*
C1	0.1253 (4)	0.4077 (12)	0.5679 (5)	0.1144 (17)
H1A	0.0700	0.3530	0.5912	0.137*
C2	0.1467 (3)	0.5877 (12)	0.6154 (4)	0.122 (2)
C3	0.2259 (4)	0.6656 (8)	0.5753 (5)	0.1049 (17)
H3	0.2404	0.7876	0.6085	0.126*
C4	0.2873 (2)	0.5700 (6)	0.4854 (4)	0.0794 (11)
C5	0.2652 (2)	0.3904 (5)	0.4421 (3)	0.0666 (10)
C6	0.1852 (3)	0.3106 (8)	0.4870 (4)	0.0921 (13)
H6	0.1721	0.1855	0.4606	0.111*
C7	0.0822 (4)	0.7033 (13)	0.7118 (7)	0.178 (4)
H7A	0.0806	0.6477	0.8114	0.267*
H7B	0.0216	0.7030	0.6630	0.267*
H7C	0.1040	0.8312	0.7212	0.267*
C8	0.3708 (4)	0.6517 (7)	0.4485 (7)	0.1135 (16)
H8A	0.3942	0.5853	0.3638	0.170*
H8B	0.4142	0.6433	0.5348	0.170*
H8C	0.3612	0.7822	0.4217	0.170*
C9	0.39175 (19)	0.1749 (4)	0.4154 (3)	0.0519 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0806 (14)	0.0787 (15)	0.0316 (11)	0.0198 (9)	0.0094 (9)	0.0014 (7)
N1	0.0824 (18)	0.0971 (19)	0.0338 (12)	0.0270 (14)	0.0098 (11)	0.0074 (11)
N2	0.0857 (18)	0.0849 (18)	0.0353 (14)	0.0251 (13)	0.0137 (11)	0.0013 (10)
C1	0.090 (3)	0.193 (5)	0.063 (2)	0.031 (3)	0.025 (2)	0.007 (3)
C2	0.068 (2)	0.245 (7)	0.053 (2)	0.063 (3)	0.0003 (17)	−0.015 (3)
C3	0.104 (3)	0.123 (3)	0.084 (3)	0.036 (3)	−0.019 (3)	−0.036 (2)
C4	0.0685 (19)	0.105 (3)	0.064 (2)	0.0184 (17)	−0.0010 (15)	−0.0088 (16)
C5	0.0682 (19)	0.090 (2)	0.0417 (16)	0.0245 (15)	0.0069 (13)	0.0057 (13)
C6	0.086 (2)	0.128 (3)	0.064 (2)	0.018 (2)	0.0218 (17)	0.0214 (19)
C7	0.106 (4)	0.316 (9)	0.112 (4)	0.091 (5)	−0.002 (3)	−0.091 (5)
C8	0.112 (3)	0.101 (3)	0.129 (4)	−0.017 (3)	0.024 (3)	0.004 (3)
C9	0.0652 (16)	0.0572 (15)	0.0342 (14)	0.0069 (11)	0.0094 (11)	−0.0013 (9)

Geometric parameters (Å, º)

O1—C9	1.236 (3)	C3—C4	1.406 (6)
N1—C9	1.340 (4)	C3—H3	0.9300
N1—C5	1.428 (4)	C4—C5	1.358 (6)
N1—H1	0.8600	C4—C8	1.407 (7)
N2—C9	1.337 (4)	C5—C6	1.377 (6)
N2—H2A	0.857 (10)	C6—H6	0.9300
N2—H2B	0.863 (10)	C7—H7A	0.9600
C1—C6	1.351 (7)	C7—H7B	0.9600
C1—C2	1.368 (10)	C7—H7C	0.9600
C1—H1A	0.9300	C8—H8A	0.9600
C2—C3	1.348 (9)	C8—H8B	0.9600
C2—C7	1.541 (6)	C8—H8C	0.9600
C9—N1—C5	121.9 (2)	C6—C5—N1	120.5 (4)
C9—N1—H1	119.1	C1—C6—C5	122.2 (6)
C5—N1—H1	119.1	C1—C6—H6	118.9
C9—N2—H2A	117 (2)	C5—C6—H6	118.9
C9—N2—H2B	115 (3)	C2—C7—H7A	109.5
H2A—N2—H2B	128 (4)	C2—C7—H7B	109.5
C6—C1—C2	119.2 (6)	H7A—C7—H7B	109.5
C6—C1—H1A	120.4	C2—C7—H7C	109.5
C2—C1—H1A	120.4	H7A—C7—H7C	109.5
C3—C2—C1	119.0 (4)	H7B—C7—H7C	109.5
C3—C2—C7	119.5 (7)	C4—C8—H8A	109.5
C1—C2—C7	121.5 (6)	C4—C8—H8B	109.5
C2—C3—C4	122.7 (5)	H8A—C8—H8B	109.5
C2—C3—H3	118.7	C4—C8—H8C	109.5
C4—C3—H3	118.7	H8A—C8—H8C	109.5
C5—C4—C3	117.1 (4)	H8B—C8—H8C	109.5
C5—C4—C8	121.0 (4)	O1—C9—N2	122.5 (2)
C3—C4—C8	121.8 (4)	O1—C9—N1	122.4 (2)
C4—C5—C6	119.7 (3)	N2—C9—N1	115.1 (2)
C4—C5—N1	119.8 (3)
C6—C1—C2—C3	2.3 (7)	C8—C4—C5—N1	−2.8 (5)
C6—C1—C2—C7	−178.3 (4)	C9—N1—C5—C4	90.7 (4)
C1—C2—C3—C4	0.5 (7)	C9—N1—C5—C6	−88.6 (4)
C7—C2—C3—C4	−178.9 (4)	C2—C1—C6—C5	−4.1 (7)
C2—C3—C4—C5	−1.6 (6)	C4—C5—C6—C1	2.9 (6)
C2—C3—C4—C8	−178.1 (5)	N1—C5—C6—C1	−177.8 (3)
C3—C4—C5—C6	−0.1 (5)	C5—N1—C9—O1	6.1 (5)
C8—C4—C5—C6	176.5 (4)	C5—N1—C9—N2	−174.4 (3)
C3—C4—C5—N1	−179.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.86	2.23	2.941 (3)	140
N2—H2A···O1^i	0.86 (1)	2.24 (2)	2.985 (3)	145 (3)
N2—H2B···O1^ii	0.86 (1)	2.12 (1)	2.977 (3)	173 (4)

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