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pk2373 scheme

Acta Cryst. (2012). E68, o234    [ doi:10.1107/S1600536811053918 ]

2-(4-Chloro-3,3,7-trimethyl-2,3-dihydro-1H-indol-2-ylidene)-2-cyanoacetamide

M. Helliwell, M. M. Baradarani, M. Alyari, A. Afghan and J. A. Joule

Abstract top

Reaction of 2-(4-chloro-3,3,7-trimethyl-2,3-dihydro-1H-indol-2-ylidene)propanedial with hydroxylamine gives the title compound, C14H14ClN3O, in which the ring N atom is essentially planar [sum of angles around the ring N atom = 361°], indicating conjugation with the 2-cyanoacrylamide unit. The orientation of the acetamide group arises from intramolecular hydrogen bonding between the indole N-H and carbonyl groups. In the crystal, inversion-related acetamide groups form N-H...O hydrogen-bonded dimers in graph-set R22(8) motifs, whilst dimers are also formed by pairs of amine-nitrile N-H...N hydrogen bonds in R22(12) motifs. These interactions together generate ribbons that propagate along the b-axis direction.

Comment top

We showed that the interaction of 2,3,3-trimethyl-3H-indoles with the Vilsmeier reagent produces (1,3-dihydro-3,3-dimethyl-2H-indol-2-ylidene)propanedials (Baradarani et al., 2006). 2,3,3-Trimethyl-2H-pyrrolo[2,3-f]quinoline, 2,3,3-trimethyl-3H-pyrrolo[3,2-h]quinoline (Rashidi et al., 2009), 2,2',3,3,3',3'-hexamethyl-3H,3'H-5,5'-biindole and 2,3,3,7,8,8-hexamethyl-3H,8H-indolo[7,6-g]indole (Rashidi et al., 2011) behave analogously. The (1,3-dihydroindol-2-ylidene)propanedials were shown to react with arylhydrazines (or hydrazine) to produce 3,3-dimethyl-2-[1-aryl-1H-pyrazol-4-yl]-3H-indoles (Baradarani et al., 2006. Rashidi et al., 2009. Helliwell et al. 2010. Rashidi et al., 2011).

In anticipation that the (1,3-dihydroindol-2-ylidene)propanedials would react with hydroxylamine to produce isoxazol-4-yl-3H-indoles, 2-(4-chloro-1,3-dihydro-3,3,7-trimethyl-2H-indol-2-ylidene)propanedial was treated with hydroxylamine in refluxing ethanol. The unexpected product of the reaction was 2-(4-chloro-1,3-dihydro-3,3,7-trimethyl-2H-indol-2-ylidene)-2- cyanoacetamide as shown by this X-ray analysis (Fig. 1).

We interpret this transformation as involving firstly formation of the diooxime 1 which cyclizes to generate aminal 2, loss of water would then produce imine 3, proton-induced fragmentation of which (arrows on 3) would then lead to the product 4 (Fig. 2).

The sum of the angles of the bonds at the ring nitrogen in 4 is 361 (4)° showing the extensive conjugation of the nitrogen with the 2-cyanoacrylamide subunit. The geometry of the double bond linking the heterocyclic and cyanoacetamide subunits is E.

The orientation of the acetamide group arises from intramolecular H bonding between the indole N—H and the carbonyl group. The inversion related acetamide groups form N—H···O hydrogen bonded dimers in graph-set R22(8) motifs (Etter et al., 1990), while dimers are also formed by pairs of NH(amine)···N(nitrile) functionalities in R22(12) motifs. These interactions together generate ribbons that propagate along the b axis direction (Fig. 3).

Related literature top

For background information on the chemistry of related compounds, see: Baradarani et al. (2006); Rashidi et al. (2009, 2011). For related structures, see; Helliwell et al. (2010, 2012). For graph-set notation, see: Etter et al. (1990).

Experimental top

A mixture of 2-(4-chloro-1,3-dihydro-3,3,7-trimethyl-2H-indol-2-ylidene)propanedial (100 mg, 0.38 mmol) and hydroxylamine hydrochloride (52 mg, 0.76 mmol) in absolute EtOH (10 ml) was heated with stirring at reflux for 7 h. After complete conversion, the reaction mixture was cooled and concentrated, and the resulting crystals were collected by filtration and recrystallized from EtOH to give the 2-(4-chloro-1,3-dihydro-3,3,7-trimethyl-2H-indol-2-ylidene)-2-cyanoacrylamide (90 mg, 86%), 522–524 K, FT—IR (KBr) νmax 3385, 3289, 3185, 2986, 2939, 2199, 1668, 1608, 1563, 1415, 1329, 909, 788 cm-1, 1H NMR (CDCl3) δ 1.84 (s, 6H, 2CH3), 2.30 (s, 3H, CH3), 5.20–6.50 (bs, 2H, NH2), 6.93 (d, J = 8.1 Hz, 1H, ArH), 7.00 (d, J = 8.1 Hz, 1H, ArH), 11.85 (bs, 1H, NH), 13C NMR (CDCl3) δ 15.9, 21.0, 51.6, 118.9, 118.9, 124.9, 127.4, 130.8, 132.5, 141.0, 169.6,177.4.

Refinement top

H atoms bonded to C were included in calculated positions using the riding method, with C—H distances of 0.98 Å and Uiso(H) = 1.5Ueq(C) for methyl H atoms and C—H distances of 0.95 Å and Uiso(H) = 1.2Ueq(C) for the aromatic H atoms. Those bonded to N were found by difference Fourier methods and refined isotropically with the N—H distances ranging from to 0.83 (5) to 0.93 (5) Å.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A plot of the title compound with ellipsoids drawn at the 50% probability level.
[Figure 2] Fig. 2. Synthesis of 2-(4-chloro-1,3-dihydro-3,3,7-trimethyl -2H-indol-2-ylidene)-2-cyanoacetamide
[Figure 3] Fig. 3. Packing arrangement of the title compound showing the H bonding which links the molecules into chains parallel to b. Only those H atoms that are involved in H bonding are shown for clarity.
2-(4-Chloro-3,3,7-trimethyl-2,3-dihydro-1H-indol-2-ylidene)-2- cyanoacetamide top
Crystal data top
C14H14ClN3OZ = 2
Mr = 275.73F(000) = 288
Triclinic, P1Dx = 1.328 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.226 (2) ÅCell parameters from 735 reflections
b = 9.282 (3) Åθ = 2.7–25.8°
c = 9.744 (3) ŵ = 0.27 mm1
α = 92.124 (5)°T = 100 K
β = 104.766 (5)°Plate, colourless
γ = 105.294 (4)°0.58 × 0.22 × 0.10 mm
V = 689.5 (3) Å3
Data collection top
Bruker SMART CCD area-detector
diffractometer
1549 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.065
graphiteθmax = 25.0°, θmin = 2.2°
φ and ω scansh = 99
3384 measured reflectionsk = 1011
2389 independent reflectionsl = 1011
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.065Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.132H atoms treated by a mixture of independent and constrained refinement
S = 1.01 w = 1/[σ2(Fo2) + (0.0419P)2]
where P = (Fo2 + 2Fc2)/3
2389 reflections(Δ/σ)max < 0.001
187 parametersΔρmax = 0.45 e Å3
0 restraintsΔρmin = 0.38 e Å3
Crystal data top
C14H14ClN3Oγ = 105.294 (4)°
Mr = 275.73V = 689.5 (3) Å3
Triclinic, P1Z = 2
a = 8.226 (2) ÅMo Kα radiation
b = 9.282 (3) ŵ = 0.27 mm1
c = 9.744 (3) ÅT = 100 K
α = 92.124 (5)°0.58 × 0.22 × 0.10 mm
β = 104.766 (5)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
1549 reflections with I > 2σ(I)
3384 measured reflectionsRint = 0.065
2389 independent reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.065H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.132Δρmax = 0.45 e Å3
S = 1.01Δρmin = 0.38 e Å3
2389 reflectionsAbsolute structure: ?
187 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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
xyzUiso*/Ueq
Cl10.29616 (14)0.79125 (12)0.38519 (11)0.0274 (3)
O10.3245 (3)0.4944 (3)0.0925 (3)0.0224 (7)
N10.0818 (4)0.5294 (4)0.2080 (3)0.0190 (8)
H1N0.140 (6)0.464 (6)0.181 (5)0.064 (17)*
N20.3940 (5)1.0145 (4)0.1147 (4)0.0306 (9)
N30.4858 (5)0.6920 (5)0.0127 (4)0.0225 (8)
H3N0.517 (5)0.783 (5)0.006 (4)0.022 (12)*
H3M0.539 (7)0.637 (6)0.013 (5)0.061 (18)*
C10.0620 (5)0.4992 (4)0.2658 (4)0.0182 (9)
C20.1558 (5)0.3606 (5)0.2912 (4)0.0207 (9)
C30.2983 (5)0.3602 (5)0.3433 (4)0.0244 (10)
H30.36930.26730.35980.029*
C40.3399 (5)0.4911 (5)0.3718 (4)0.0241 (10)
H40.43700.48780.40870.029*
C50.2383 (5)0.6280 (5)0.3461 (4)0.0218 (10)
C60.0984 (5)0.6349 (4)0.2903 (4)0.0179 (9)
C70.0298 (5)0.7621 (4)0.2452 (4)0.0174 (9)
C80.1405 (5)0.6759 (4)0.1913 (4)0.0194 (9)
C90.1084 (5)0.2188 (4)0.2602 (5)0.0271 (10)
H9A0.08650.21710.16600.041*
H9B0.20530.13120.26130.041*
H9C0.00270.21610.33320.041*
C100.0645 (5)0.8363 (4)0.1230 (4)0.0233 (10)
H10A0.02180.91690.09620.035*
H10B0.14810.87840.15460.035*
H10C0.12740.76100.04030.035*
C110.1435 (5)0.8796 (5)0.3722 (4)0.0262 (10)
H11A0.20780.83070.44600.039*
H11B0.06810.92530.41170.039*
H11C0.22680.95770.33970.039*
C120.2765 (5)0.7319 (4)0.1318 (4)0.0183 (9)
C130.3378 (5)0.8890 (5)0.1241 (4)0.0216 (10)
C140.3650 (5)0.6315 (4)0.0777 (4)0.0174 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0283 (6)0.0262 (7)0.0351 (7)0.0153 (5)0.0142 (5)0.0008 (5)
O10.0237 (16)0.0140 (17)0.0356 (18)0.0083 (12)0.0150 (13)0.0072 (13)
N10.0193 (19)0.015 (2)0.027 (2)0.0076 (15)0.0104 (16)0.0061 (15)
N20.031 (2)0.019 (2)0.048 (2)0.0074 (18)0.0209 (19)0.0073 (19)
N30.023 (2)0.015 (2)0.035 (2)0.0071 (17)0.0143 (17)0.0068 (18)
C10.015 (2)0.024 (2)0.020 (2)0.0082 (18)0.0094 (18)0.0058 (18)
C20.020 (2)0.022 (2)0.022 (2)0.0093 (19)0.0067 (18)0.0052 (18)
C30.026 (2)0.022 (2)0.028 (2)0.0052 (19)0.012 (2)0.0083 (19)
C40.017 (2)0.033 (3)0.025 (2)0.007 (2)0.0097 (19)0.004 (2)
C50.024 (2)0.021 (2)0.024 (2)0.0132 (19)0.0052 (19)0.0006 (19)
C60.017 (2)0.020 (2)0.019 (2)0.0095 (18)0.0057 (18)0.0044 (18)
C70.014 (2)0.018 (2)0.024 (2)0.0087 (17)0.0070 (18)0.0033 (18)
C80.020 (2)0.017 (2)0.021 (2)0.0086 (18)0.0017 (18)0.0054 (18)
C90.030 (3)0.018 (2)0.037 (3)0.007 (2)0.015 (2)0.009 (2)
C100.021 (2)0.019 (2)0.032 (3)0.0074 (18)0.0093 (19)0.0061 (19)
C110.028 (3)0.026 (3)0.026 (2)0.012 (2)0.0059 (19)0.000 (2)
C120.019 (2)0.013 (2)0.026 (2)0.0092 (17)0.0069 (18)0.0057 (18)
C130.017 (2)0.022 (3)0.031 (2)0.0081 (19)0.0137 (19)0.004 (2)
C140.016 (2)0.016 (2)0.021 (2)0.0073 (17)0.0013 (18)0.0027 (18)
Geometric parameters (Å, °) top
Cl1—C51.760 (4)C5—C61.381 (5)
O1—C141.251 (4)C6—C71.523 (5)
N1—C81.349 (5)C7—C81.531 (5)
N1—C11.404 (4)C7—C111.538 (5)
N1—H1N0.93 (5)C7—C101.538 (5)
N2—C131.151 (5)C8—C121.380 (5)
N3—C141.326 (5)C9—H9A0.9800
N3—H3N0.85 (4)C9—H9B0.9800
N3—H3M0.83 (5)C9—H9C0.9800
C1—C21.381 (5)C10—H10A0.9800
C1—C61.395 (5)C10—H10B0.9800
C2—C31.391 (5)C10—H10C0.9800
C2—C91.509 (5)C11—H11A0.9800
C3—C41.383 (5)C11—H11B0.9800
C3—H30.9500C11—H11C0.9800
C4—C51.395 (5)C12—C131.424 (5)
C4—H40.9500C12—C141.481 (5)
C8—N1—C1112.7 (3)C11—C7—C10111.0 (3)
C8—N1—H1N118 (3)N1—C8—C12123.4 (3)
C1—N1—H1N130 (3)N1—C8—C7108.8 (3)
C14—N3—H3N128 (3)C12—C8—C7127.8 (4)
C14—N3—H3M118 (3)C2—C9—H9A109.5
H3N—N3—H3M114 (4)C2—C9—H9B109.5
C2—C1—C6125.2 (3)H9A—C9—H9B109.5
C2—C1—N1127.0 (3)C2—C9—H9C109.5
C6—C1—N1107.8 (3)H9A—C9—H9C109.5
C1—C2—C3115.8 (4)H9B—C9—H9C109.5
C1—C2—C9121.7 (3)C7—C10—H10A109.5
C3—C2—C9122.5 (4)C7—C10—H10B109.5
C4—C3—C2121.9 (4)H10A—C10—H10B109.5
C4—C3—H3119.0C7—C10—H10C109.5
C2—C3—H3119.0H10A—C10—H10C109.5
C3—C4—C5119.6 (3)H10B—C10—H10C109.5
C3—C4—H4120.2C7—C11—H11A109.5
C5—C4—H4120.2C7—C11—H11B109.5
C6—C5—C4121.1 (4)H11A—C11—H11B109.5
C6—C5—Cl1121.2 (3)C7—C11—H11C109.5
C4—C5—Cl1117.7 (3)H11A—C11—H11C109.5
C5—C6—C1116.4 (4)H11B—C11—H11C109.5
C5—C6—C7133.7 (4)C8—C12—C13120.4 (3)
C1—C6—C7109.9 (3)C8—C12—C14121.2 (3)
C6—C7—C8100.8 (3)C13—C12—C14118.4 (3)
C6—C7—C11111.8 (3)N2—C13—C12176.3 (4)
C8—C7—C11110.9 (3)O1—C14—N3122.0 (4)
C6—C7—C10111.6 (3)O1—C14—C12120.4 (3)
C8—C7—C10110.2 (3)N3—C14—C12117.6 (4)
C8—N1—C1—C2177.6 (4)C5—C6—C7—C1163.5 (6)
C8—N1—C1—C60.8 (4)C1—C6—C7—C11117.4 (4)
C6—C1—C2—C31.0 (6)C5—C6—C7—C1061.6 (6)
N1—C1—C2—C3177.1 (4)C1—C6—C7—C10117.5 (4)
C6—C1—C2—C9179.4 (4)C1—N1—C8—C12177.6 (4)
N1—C1—C2—C91.2 (6)C1—N1—C8—C71.1 (4)
C1—C2—C3—C41.9 (6)C6—C7—C8—N11.0 (4)
C9—C2—C3—C4179.7 (4)C11—C7—C8—N1117.6 (4)
C2—C3—C4—C50.9 (6)C10—C7—C8—N1119.0 (4)
C3—C4—C5—C61.1 (6)C6—C7—C8—C12177.7 (4)
C3—C4—C5—Cl1179.6 (3)C11—C7—C8—C1263.7 (5)
C4—C5—C6—C12.0 (6)C10—C7—C8—C1259.7 (5)
Cl1—C5—C6—C1178.8 (3)N1—C8—C12—C13176.7 (4)
C4—C5—C6—C7177.0 (4)C7—C8—C12—C134.7 (6)
Cl1—C5—C6—C72.2 (6)N1—C8—C12—C141.8 (6)
C2—C1—C6—C50.9 (6)C7—C8—C12—C14176.7 (4)
N1—C1—C6—C5179.3 (3)C8—C12—C14—O14.2 (6)
C2—C1—C6—C7178.3 (4)C13—C12—C14—O1174.4 (4)
N1—C1—C6—C70.1 (4)C8—C12—C14—N3175.2 (4)
C5—C6—C7—C8178.5 (4)C13—C12—C14—N36.2 (6)
C1—C6—C7—C80.5 (4)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1N···O10.93 (5)1.89 (5)2.610 (4)132 (4)
N3—H3M···O1i0.83 (5)2.11 (5)2.931 (5)176 (5)
N3—H3N···N2ii0.85 (4)2.24 (4)3.065 (5)163 (3)
Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+1, −y+2, −z.
Table 1
Hydrogen-bond geometry (Å, °)
top
D—H···AD—HH···AD···AD—H···A
N1—H1N···O10.93 (5)1.89 (5)2.610 (4)132 (4)
N3—H3M···O1i0.83 (5)2.11 (5)2.931 (5)176 (5)
N3—H3N···N2ii0.85 (4)2.24 (4)3.065 (5)163 (3)
Symmetry codes: (i) −x+1, −y+1, −z; (ii) −x+1, −y+2, −z.
Acknowledgements top

The authors are grateful to the University of Urmia for financial support of this work.

references
References top

Baradarani, M. M., Afghan, A., Zebarjadi, F., Hasanzadeh, K. & Joule, J. A. (2006). J. Heterocycl. Chem. 43, 1591–1596.

Bruker (2001). SMART and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.

Bruker (2002). SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262.

Helliwell, M., Afghan, A., Keshvari, F., Baradarani, M. M. & Joule, J. A. (2010). Acta Cryst. E66, o112.

Helliwell, M., Baradarani, M. M., Mohammadnejadaghdam, R., Afghan, A. & Joule, J. A. (2012). Acta Cryst. E68, o??? [ZQ2144].

Rashidi, A., Afghan, A., Baradarani, M. M. & Joule, J. A. (2009). J. Heterocycl. Chem. 46, 428–431.

Rashidi, A., Baradarani, M. M. & Joule, J. A. (2011). ARKIVOC, ii, 252–259.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.