2-[(E)-(Dimethyl­amino)methyl­ene­amino]benzonitrile

Abstract

In the title compound, C₁₀H₁₁N₃, the amidine unit, including the two methyl substituents, is virtually planar [maximum deviation = 0.016 (5) Å]. The plane of the benzene ring forms a dihedral angle of 46.5 (3)° with the amidine group.

Related literature

For application of formamidines in chemical synthesis, see: Deshpande & Seshadri (1973 ▶); Toste et al. (1994 ▶).

Experimental

Crystal data

• C₁₀H₁₁N₃

• M _r = 173.22

• Monoclinic,

• a = 7.7468 (15) Å

• b = 11.212 (2) Å

• c = 11.042 (2) Å

• β = 109.67 (3)°

• V = 903.1 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.08 mm⁻¹

• T = 113 K

• 0.20 × 0.18 × 0.14 mm

Data collection

• Rigaku Saturn diffractometer

• Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ▶) T _min = 0.984, T _max = 0.989

• 5746 measured reflections

• 1575 independent reflections

• 1342 reflections with I > 2σ(I)

• R _int = 0.027

Refinement

• R[F ² > 2σ(F ²)] = 0.035

• wR(F ²) = 0.100

• S = 1.10

• 1575 reflections

• 120 parameters

• H-atom parameters constrained

• Δρ_max = 0.19 e Å⁻³

• Δρ_min = −0.17 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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.

Supplementary Material

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

supplementary crystallographic information

Comment

Derivatives of formamidine are valuable synthetic intermediates featuring common structural motif found in a variety of compounds with interesting medicinal and biological properties. The formamidine group is a useful primary amine protecting group for its ease of introduction and efficient removal (Toste et al., 1994). The N'-(2-cyanophenyl)-N,N-dimethylformamidine compounds are key intermediates of convenient synthesis of O-aminobenzonitrile, 4-aminoquinazolines and 4-aminoquinazoline-3-oxides (Deshpande et al., 1973).

Experimental

Phosphorus oxychloride (13 mmole) was added dropwise to 8 ml dimethylformamide at 273 K. After stirring for 2–3 min, finely powdered isatin-3-oxime (10 mmol) was added and kept at room temperature for some time. Temperature was then gradually raised to 343 K and the reaction mixture was kept at this temperature for 2hr, then cooled, poured onto crushed ice and filtered. The clear filtrate was basified by sodium carbonate to pH=9 and the solution extracted with toluene, which was then evaporated to obtain crude (E)-N'-(2-cyanophenyl)-N,N-dimethylformamidine. The compound was recrystallizated from ethyl acetate and petroleum ether to give colorless crystals.

m.p. 338–339 K; IR(KBr): 2910 (C—H), 2214.87 (–CN), 1587, 1556 (C—C), 1367 (–CH3) cm^-1; 1H-NMR (CDCl3, p.p.m): 3.07–3.09 (6H, m), 6.93–7.02(2H, m), 7.38–7.44 (1H, t), 7.51–7.54 (1H, d), 7.58 (1H, s); ESI: 174.1[M+H]⁺. Elementary analysis: found N 24.31, C 69.31, H 6.30; calc. 24.26, 69.34, 6.40).

20 mg of the obtained product was dissolved in ethyl acetate (5 ml). Then petroleum ether (2 ml) was added dropwise to the solution. The solution was kept at room temperature for 4 days to give colorless single crystals.

Refinement

All H atoms were included in calculated positions and refined in the riding model approximation with C—H distances 0.93 (aromatic) or 0.96 Å (methyl), and with U_iso=1.2U_eq or 1.5U_eq(methyl).

Figures

Fig. 1.

Molecular structure of the title compound with displacement ellipsoids drawn at the 30% probability level.

Crystal data

C10H11N3	F(000) = 368
Mr = 173.22	Dx = 1.274 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -p 2yn	Cell parameters from 2901 reflections
a = 7.7468 (15) Å	θ = 1.8–27.9°
b = 11.212 (2) Å	µ = 0.08 mm−1
c = 11.042 (2) Å	T = 113 K
β = 109.67 (3)°	Cube, colorless
V = 903.1 (3) Å3	0.20 × 0.18 × 0.14 mm
Z = 4

Data collection

Rigaku Saturn diffractometer	1575 independent reflections
Radiation source: rotating anode	1342 reflections with I > 2σ(I)
confocal	Rint = 0.027
ω scans	θmax = 25.0°, θmin = 2.7°
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005)	h = −9→8
Tmin = 0.984, Tmax = 0.989	k = −13→13
5746 measured reflections	l = −13→13

Refinement

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)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.100	H-atom parameters constrained
S = 1.10	w = 1/[σ2(Fo2) + (0.0612P)2 + 0.137P] where P = (Fo2 + 2Fc2)/3
1575 reflections	(Δ/σ)max = 0.001
120 parameters	Δρmax = 0.19 e Å−3
0 restraints	Δρmin = −0.17 e Å−3

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 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 (Ų)

	x	y	z	Uiso*/Ueq
N1	−0.14481 (15)	0.99786 (9)	0.10732 (10)	0.0224 (3)
N2	0.07129 (13)	0.79099 (9)	0.36257 (9)	0.0164 (3)
N3	0.06421 (14)	0.76114 (9)	0.56842 (9)	0.0188 (3)
C1	−0.06597 (16)	0.90883 (10)	0.12357 (11)	0.0161 (3)
C2	0.02451 (15)	0.79498 (10)	0.13459 (11)	0.0149 (3)
C3	0.04571 (16)	0.74551 (11)	0.02435 (11)	0.0175 (3)
H3	0.0069	0.7875	−0.0527	0.021*
C4	0.12454 (16)	0.63393 (11)	0.02985 (12)	0.0189 (3)
H4	0.1380	0.6005	−0.0435	0.023*
C5	0.18342 (16)	0.57226 (11)	0.14586 (11)	0.0177 (3)
H5	0.2354	0.4970	0.1496	0.021*
C6	0.16547 (15)	0.62165 (10)	0.25572 (11)	0.0163 (3)
H6	0.2079	0.5795	0.3326	0.020*
C7	0.08444 (16)	0.73434 (11)	0.25378 (11)	0.0145 (3)
C8	0.04348 (16)	0.72373 (11)	0.45021 (11)	0.0170 (3)
H8	0.0071	0.6452	0.4290	0.020*
C9	0.02345 (19)	0.68383 (12)	0.66108 (13)	0.0272 (3)
H9A	−0.0296	0.6108	0.6197	0.041*
H9B	−0.0615	0.7231	0.6941	0.041*
H9C	0.1345	0.6666	0.7305	0.041*
C10	0.13692 (18)	0.87915 (11)	0.61196 (12)	0.0231 (3)
H10A	0.2098	0.9060	0.5621	0.035*
H10B	0.2115	0.8756	0.7011	0.035*
H10C	0.0374	0.9337	0.6014	0.035*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
N1	0.0285 (6)	0.0188 (6)	0.0200 (6)	0.0012 (5)	0.0085 (5)	0.0002 (4)
N2	0.0166 (5)	0.0180 (5)	0.0143 (5)	0.0000 (4)	0.0048 (4)	0.0003 (4)
N3	0.0216 (6)	0.0221 (6)	0.0146 (6)	0.0030 (4)	0.0086 (4)	0.0022 (4)
C1	0.0171 (6)	0.0187 (6)	0.0116 (6)	−0.0043 (5)	0.0038 (5)	−0.0009 (5)
C2	0.0126 (6)	0.0145 (6)	0.0169 (6)	−0.0025 (5)	0.0038 (5)	−0.0002 (4)
C3	0.0174 (6)	0.0197 (6)	0.0138 (6)	−0.0019 (5)	0.0033 (5)	0.0018 (5)
C4	0.0195 (6)	0.0207 (6)	0.0163 (6)	−0.0019 (5)	0.0057 (5)	−0.0045 (5)
C5	0.0156 (6)	0.0154 (6)	0.0210 (6)	−0.0001 (5)	0.0044 (5)	−0.0014 (5)
C6	0.0146 (6)	0.0171 (6)	0.0154 (6)	−0.0023 (5)	0.0025 (5)	0.0027 (5)
C7	0.0110 (6)	0.0171 (6)	0.0145 (6)	−0.0049 (4)	0.0029 (5)	−0.0011 (4)
C8	0.0145 (6)	0.0180 (6)	0.0184 (7)	0.0018 (5)	0.0053 (5)	0.0008 (5)
C9	0.0312 (7)	0.0328 (8)	0.0228 (7)	0.0074 (6)	0.0159 (6)	0.0092 (6)
C10	0.0243 (7)	0.0269 (7)	0.0182 (7)	0.0031 (6)	0.0071 (5)	−0.0046 (5)

Geometric parameters (Å, °)

N1—C1	1.1522 (15)	C4—H4	0.9300
N2—C8	1.3007 (15)	C5—C6	1.3825 (16)
N2—C7	1.3925 (15)	C5—H5	0.9300
N3—C8	1.3283 (15)	C6—C7	1.4077 (17)
N3—C9	1.4544 (15)	C6—H6	0.9300
N3—C10	1.4549 (16)	C8—H8	0.9300
C1—C2	1.4415 (16)	C9—H9A	0.9600
C2—C3	1.3967 (16)	C9—H9B	0.9600
C2—C7	1.4137 (17)	C9—H9C	0.9600
C3—C4	1.3844 (17)	C10—H10A	0.9600
C3—H3	0.9300	C10—H10B	0.9600
C4—C5	1.3906 (17)	C10—H10C	0.9600
C8—N2—C7	117.12 (10)	C7—C6—H6	119.3
C8—N3—C9	121.34 (11)	N2—C7—C6	123.91 (11)
C8—N3—C10	121.14 (10)	N2—C7—C2	119.17 (11)
C9—N3—C10	117.46 (10)	C6—C7—C2	116.79 (10)
N1—C1—C2	175.84 (12)	N2—C8—N3	123.54 (11)
C3—C2—C7	121.49 (11)	N2—C8—H8	118.2
C3—C2—C1	118.33 (10)	N3—C8—H8	118.2
C7—C2—C1	120.15 (10)	N3—C9—H9A	109.5
C4—C3—C2	120.01 (11)	N3—C9—H9B	109.5
C4—C3—H3	120.0	H9A—C9—H9B	109.5
C2—C3—H3	120.0	N3—C9—H9C	109.5
C3—C4—C5	119.52 (11)	H9A—C9—H9C	109.5
C3—C4—H4	120.2	H9B—C9—H9C	109.5
C5—C4—H4	120.2	N3—C10—H10A	109.5
C6—C5—C4	120.70 (11)	N3—C10—H10B	109.5
C6—C5—H5	119.7	H10A—C10—H10B	109.5
C4—C5—H5	119.7	N3—C10—H10C	109.5
C5—C6—C7	121.48 (11)	H10A—C10—H10C	109.5
C5—C6—H6	119.3	H10B—C10—H10C	109.5
C7—C2—C3—C4	0.94 (17)	C5—C6—C7—C2	−0.75 (16)
C1—C2—C3—C4	−177.12 (10)	C3—C2—C7—N2	175.72 (9)
C2—C3—C4—C5	−0.49 (17)	C1—C2—C7—N2	−6.25 (16)
C3—C4—C5—C6	−0.57 (17)	C3—C2—C7—C6	−0.32 (16)
C4—C5—C6—C7	1.21 (17)	C1—C2—C7—C6	177.71 (10)
C8—N2—C7—C6	−35.50 (15)	C7—N2—C8—N3	166.09 (11)
C8—N2—C7—C2	148.77 (11)	C9—N3—C8—N2	177.22 (10)
C5—C6—C7—N2	−176.58 (10)	C10—N3—C8—N2	−5.75 (18)