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Acta Crystallogr Sect E Struct Rep Online. 2010 March 1; 66(Pt 3): o500.
Published online 2010 February 3. doi:  10.1107/S1600536810003260
PMCID: PMC2983729

(Z)-Ethyl 3-(2,6-diisopropyl­anilino)but-2-enoate

Abstract

The title compound, C18H27NO2, crystallizes as the enamine form with Z geometry. The β-enamino­ester fragment forms a dihedral angle of 87.5 (1)° with the isopropyl­phenyl frame. The structure exhibits an intra­molecular N—H(...)O hydrogen bond. In addition, in the crystal, mol­ecules are linked by a centrosymmetric inter­molecular N—H(...)O hydrogen bond.

Related literature

For methods used in the preparation of β-enamino­ketones and β-enamino­esters, see: Zhang & Yang (2009 [triangle]); Bartoli et al. (2004 [triangle]); Braibante et al. (2006 [triangle]). These compounds are used the preparation of key inter­mediates of pharmaceutical products (Michael et al., 1999 [triangle]), amino­acids (Palmieri & Cimmerelli, 1996 [triangle]), peptides and alkaloids (David et al., 1999 [triangle]). For our work on the synthesis of enamino­esters, see: Amézquita-Valencia et al. (2009 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-0o500-scheme1.jpg

Experimental

Crystal data

  • C18H27NO2
  • M r = 289.41
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-0o500-efi1.jpg
  • a = 8.4750 (17) Å
  • b = 8.8995 (18) Å
  • c = 11.956 (2) Å
  • α = 94.901 (3)°
  • β = 91.801 (3)°
  • γ = 101.255 (4)°
  • V = 880.1 (3) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.07 mm−1
  • T = 298 K
  • 0.29 × 0.21 × 0.05 mm

Data collection

  • Bruker SMART APEX CCD area-detector diffractometer
  • 7319 measured reflections
  • 3233 independent reflections
  • 1574 reflections with I > 2σ(I)
  • R int = 0.052

Refinement

  • R[F 2 > 2σ(F 2)] = 0.041
  • wR(F 2) = 0.085
  • S = 0.84
  • 3233 reflections
  • 199 parameters
  • 1 restraint
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.11 e Å−3
  • Δρmin = −0.10 e Å−3

Data collection: SMART (Bruker, 1999 [triangle]); cell refinement: SAINT (Bruker, 1999 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Table 1
Selected Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810003260/gw2075sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810003260/gw2075Isup2.hkl

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

Acknowledgments

MAV and AC thank DGAPA–UNAM for financial support (PAPIIT IN203209) and CONACyT (Fellowship 229448).

supplementary crystallographic information

Comment

Several methods have been carried out in the β-enaminoketones and β-enaminoesters preparations, for instances; catalysis by silica-supported antimony (III) chloride (Zhang & Yang, 2009), the use of Lewis acids (Bartoli, et al. 2004) solid acids such as montmorillonite K10 (Braibante, et al. 2006). Is necessary to improve this reaction, due to the named compounds are important precursors in organic synthesis, these are particularly useful as they can be further transformed to key intermediates of several pharmaceutical products (Michael et al., 1999). They have been utilized for the preparation of different important aminoacids (Palmieri et al., 1996), peptides and alkaloids (David et al., 1999). In continuation of our work in enaminoesters synthesis (Amézquita-Valencia, et al. 2009), we describe the structure of title compound (I) obtained using a Mexican bentonitic clay as catalist.

The structure with numbering scheme of the title compound is shown in fig. 1. The 2,6-diisopropylphenyl substituent is almost perpendicular to the β-enaminoester function (dihedral angle 87.5°), similar to described in ethyl 3-(2,6-dimethylphenylamino)but-2-enoate (Amézquita-Valencia, et al. 2009). A strong intramolecular N—H···O hydrogen bond is present in the structure, in addition, the molecules are linked by centrosymmetric intermolecular N—H···O hydrogen bond, the symmetry code is 1-x, -y 1-z, fig. 2.

Experimental

Compound (I) was obtained following the procedure described in Amézquita-Valencia, et al. 2009. The product recrystallized from methanol. Yield: 92%, M.p. 326.3°

Refinement

H atom on amine group was found in Fourier map and refined with Uiso(H) = 1.2 UeqC(sp2). H on C atoms were placed in geometrically idealized positions [0.93 Å(CH) 0.96 Å(CH arom) and 0.97 Å (CH3)] tied to the parent atom with Uiso(H) = 1.2 UeqC(sp2) and 1.5 UeqC(sp3) and refined using the riding model.

Figures

Fig. 1.
The Molecular structure of (I) with the atom numbering scheme. Displacement ellipsoids are drawn at the 40% probability level. H atoms bonded to C omitted. The intramolecular hydrogen bond is shown as a dashed line.
Fig. 2.
The centrosymmetric intermolecular N—H···O hydrogen bonding network in dashes lines. symmetry code 1-x, -y, 1-z.

Crystal data

C18H27NO2Z = 2
Mr = 289.41F(000) = 316
Triclinic, P1Dx = 1.092 Mg m3
Hall symbol: -P 1Melting point: 326.3(2) K
a = 8.4750 (17) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.8995 (18) ÅCell parameters from 1942 reflections
c = 11.956 (2) Åθ = 2.5–24.1°
α = 94.901 (3)°µ = 0.07 mm1
β = 91.801 (3)°T = 298 K
γ = 101.255 (4)°Prism, colorless
V = 880.1 (3) Å30.29 × 0.21 × 0.05 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer1574 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.052
graphiteθmax = 25.4°, θmin = 1.7°
Detector resolution: 0.83 pixels mm-1h = −10→10
ω scansk = −10→10
7319 measured reflectionsl = −14→14
3233 independent reflections

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.041Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.085H atoms treated by a mixture of independent and constrained refinement
S = 0.84w = 1/[σ2(Fo2) + (0.020P)2] where P = (Fo2 + 2Fc2)/3
3233 reflections(Δ/σ)max < 0.001
199 parametersΔρmax = 0.11 e Å3
1 restraintΔρmin = −0.10 e Å3

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.
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)

xyzUiso*/Ueq
O10.40766 (16)0.15127 (14)0.48653 (10)0.0730 (4)
O20.30098 (15)0.36079 (13)0.46776 (9)0.0683 (4)
N10.49463 (18)0.01679 (16)0.28928 (11)0.0554 (4)
H10.4882 (18)0.0192 (18)0.3638 (8)0.066*
C10.3661 (2)0.2415 (2)0.42624 (15)0.0556 (5)
C20.3774 (2)0.23743 (19)0.30792 (14)0.0574 (5)
H20.34040.31290.27130.069*
C30.4383 (2)0.1311 (2)0.24509 (14)0.0521 (5)
C40.4449 (2)0.1348 (2)0.12035 (14)0.0821 (7)
H4A0.55520.15260.09990.123*
H4B0.39520.21610.09740.123*
H4C0.38850.03820.08380.123*
C50.5595 (2)−0.1002 (2)0.22757 (13)0.0508 (5)
C60.7234 (2)−0.0729 (2)0.20876 (14)0.0579 (5)
C70.7848 (2)−0.1914 (3)0.15333 (15)0.0697 (6)
H70.8937−0.17630.13920.084*
C80.6859 (3)−0.3301 (3)0.11939 (15)0.0710 (6)
H80.7291−0.40910.08420.085*
C90.5242 (3)−0.3537 (2)0.13675 (14)0.0638 (5)
H90.4591−0.44800.11180.077*
C100.4557 (2)−0.2397 (2)0.19079 (13)0.0529 (5)
C110.8341 (2)0.0779 (2)0.24878 (18)0.0793 (6)
H110.76570.15340.26500.095*
C120.9507 (3)0.1411 (3)0.1612 (2)0.1274 (9)
H12A1.02690.07530.14860.191*
H12B1.00680.24280.18790.191*
H12C0.89150.14480.09200.191*
C130.9264 (3)0.0662 (3)0.35821 (18)0.1140 (8)
H13A0.85160.04120.41570.171*
H13B0.99720.16280.38070.171*
H13C0.9884−0.01290.34710.171*
C140.2780 (2)−0.2639 (2)0.21149 (15)0.0665 (5)
H140.2455−0.16500.20530.080*
C150.2454 (2)−0.3071 (2)0.33083 (17)0.0971 (7)
H15A0.2766−0.40350.34030.146*
H15B0.1326−0.31640.34310.146*
H15C0.3064−0.22860.38400.146*
C160.1727 (2)−0.3808 (2)0.12593 (19)0.1022 (8)
H16A0.1915−0.35030.05160.153*
H16B0.0614−0.38550.14120.153*
H16C0.1988−0.48030.13110.153*
C170.2874 (3)0.3794 (2)0.58714 (14)0.0862 (7)
H17A0.39300.39400.62490.103*
H17B0.22020.28840.61200.103*
C180.2146 (2)0.5158 (2)0.61480 (15)0.0817 (6)
H18A0.28110.60510.58910.123*
H18B0.20640.53120.69470.123*
H18C0.10920.49940.57850.123*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.1105 (11)0.0678 (9)0.0517 (8)0.0418 (8)0.0065 (7)0.0118 (7)
O20.1025 (11)0.0614 (8)0.0497 (8)0.0382 (8)0.0095 (7)0.0023 (6)
N10.0797 (11)0.0503 (9)0.0418 (8)0.0262 (8)0.0075 (8)0.0038 (8)
C10.0659 (14)0.0490 (12)0.0539 (12)0.0173 (11)0.0035 (10)0.0014 (10)
C20.0800 (14)0.0495 (11)0.0487 (11)0.0265 (10)0.0032 (10)0.0070 (9)
C30.0637 (13)0.0487 (11)0.0461 (11)0.0158 (10)0.0014 (9)0.0067 (9)
C40.1282 (19)0.0817 (15)0.0491 (11)0.0482 (14)0.0115 (11)0.0131 (11)
C50.0670 (14)0.0497 (12)0.0405 (10)0.0222 (11)0.0045 (10)0.0052 (9)
C60.0666 (15)0.0558 (13)0.0546 (11)0.0179 (12)0.0060 (10)0.0089 (10)
C70.0696 (15)0.0803 (15)0.0657 (13)0.0283 (14)0.0127 (11)0.0091 (12)
C80.0917 (18)0.0764 (16)0.0537 (12)0.0419 (14)0.0057 (12)−0.0036 (11)
C90.0837 (16)0.0548 (12)0.0541 (12)0.0210 (12)−0.0033 (11)−0.0027 (10)
C100.0703 (15)0.0498 (12)0.0429 (10)0.0222 (11)0.0012 (10)0.0050 (9)
C110.0711 (15)0.0695 (15)0.0960 (17)0.0116 (13)0.0051 (13)0.0055 (13)
C120.112 (2)0.124 (2)0.139 (2)−0.0138 (17)0.0189 (18)0.0496 (18)
C130.117 (2)0.1073 (19)0.0989 (18)−0.0166 (16)−0.0228 (16)0.0004 (15)
C140.0711 (15)0.0559 (13)0.0741 (14)0.0173 (11)0.0021 (11)0.0060 (11)
C150.0893 (18)0.1064 (18)0.0986 (17)0.0148 (14)0.0304 (14)0.0286 (15)
C160.0800 (17)0.0877 (17)0.132 (2)0.0130 (14)−0.0184 (15)−0.0127 (15)
C170.137 (2)0.0852 (15)0.0495 (12)0.0540 (15)0.0167 (12)0.0017 (11)
C180.1002 (17)0.0771 (15)0.0726 (14)0.0309 (13)0.0199 (12)−0.0032 (11)

Geometric parameters (Å, °)

O1—C11.2173 (18)C11—C131.525 (3)
O2—C11.3543 (18)C11—C121.529 (2)
O2—C171.4337 (18)C11—H110.9800
N1—C31.3439 (19)C12—H12A0.9600
N1—C51.4310 (19)C12—H12B0.9600
N1—H10.894 (8)C12—H12C0.9600
C1—C21.419 (2)C13—H13A0.9600
C2—C31.350 (2)C13—H13B0.9600
C2—H20.9300C13—H13C0.9600
C3—C41.497 (2)C14—C161.525 (2)
C4—H4A0.9600C14—C151.529 (2)
C4—H4B0.9600C14—H140.9800
C4—H4C0.9600C15—H15A0.9600
C5—C61.392 (2)C15—H15B0.9600
C5—C101.402 (2)C15—H15C0.9600
C6—C71.392 (2)C16—H16A0.9600
C6—C111.510 (2)C16—H16B0.9600
C7—C81.371 (3)C16—H16C0.9600
C7—H70.9300C17—C181.483 (2)
C8—C91.370 (2)C17—H17A0.9700
C8—H80.9300C17—H17B0.9700
C9—C101.388 (2)C18—H18A0.9600
C9—H90.9300C18—H18B0.9600
C10—C141.510 (2)C18—H18C0.9600
C1—O2—C17116.95 (14)C11—C12—H12A109.5
C3—N1—C5125.68 (14)C11—C12—H12B109.5
C3—N1—H1113.3 (10)H12A—C12—H12B109.5
C5—N1—H1121.1 (10)C11—C12—H12C109.5
O1—C1—O2121.97 (16)H12A—C12—H12C109.5
O1—C1—C2126.24 (17)H12B—C12—H12C109.5
O2—C1—C2111.79 (16)C11—C13—H13A109.5
C3—C2—C1124.19 (16)C11—C13—H13B109.5
C3—C2—H2117.9H13A—C13—H13B109.5
C1—C2—H2117.9C11—C13—H13C109.5
N1—C3—C2122.83 (15)H13A—C13—H13C109.5
N1—C3—C4116.49 (15)H13B—C13—H13C109.5
C2—C3—C4120.68 (15)C10—C14—C16113.93 (16)
C3—C4—H4A109.5C10—C14—C15111.14 (15)
C3—C4—H4B109.5C16—C14—C15110.36 (17)
H4A—C4—H4B109.5C10—C14—H14107.0
C3—C4—H4C109.5C16—C14—H14107.0
H4A—C4—H4C109.5C15—C14—H14107.0
H4B—C4—H4C109.5C14—C15—H15A109.5
C6—C5—C10122.50 (16)C14—C15—H15B109.5
C6—C5—N1118.98 (17)H15A—C15—H15B109.5
C10—C5—N1118.49 (17)C14—C15—H15C109.5
C7—C6—C5117.78 (18)H15A—C15—H15C109.5
C7—C6—C11120.22 (19)H15B—C15—H15C109.5
C5—C6—C11121.99 (17)C14—C16—H16A109.5
C8—C7—C6120.58 (19)C14—C16—H16B109.5
C8—C7—H7119.7H16A—C16—H16B109.5
C6—C7—H7119.7C14—C16—H16C109.5
C9—C8—C7120.76 (18)H16A—C16—H16C109.5
C9—C8—H8119.6H16B—C16—H16C109.5
C7—C8—H8119.6O2—C17—C18108.30 (15)
C8—C9—C10121.37 (19)O2—C17—H17A110.0
C8—C9—H9119.3C18—C17—H17A110.0
C10—C9—H9119.3O2—C17—H17B110.0
C9—C10—C5116.97 (17)C18—C17—H17B110.0
C9—C10—C14122.14 (18)H17A—C17—H17B108.4
C5—C10—C14120.88 (16)C17—C18—H18A109.5
C6—C11—C13111.31 (17)C17—C18—H18B109.5
C6—C11—C12113.78 (18)H18A—C18—H18B109.5
C13—C11—C12110.29 (19)C17—C18—H18C109.5
C6—C11—H11107.0H18A—C18—H18C109.5
C13—C11—H11107.0H18B—C18—H18C109.5
C12—C11—H11107.0
C17—O2—C1—O11.9 (2)C7—C8—C9—C10−1.2 (3)
C17—O2—C1—C2−178.36 (16)C8—C9—C10—C5−0.6 (2)
O1—C1—C2—C3−0.6 (3)C8—C9—C10—C14−179.51 (16)
O2—C1—C2—C3179.68 (17)C6—C5—C10—C91.9 (2)
C5—N1—C3—C2179.47 (17)N1—C5—C10—C9−176.47 (13)
C5—N1—C3—C40.0 (3)C6—C5—C10—C14−179.16 (14)
C1—C2—C3—N10.2 (3)N1—C5—C10—C142.5 (2)
C1—C2—C3—C4179.67 (17)C7—C6—C11—C13−79.3 (2)
C3—N1—C5—C688.8 (2)C5—C6—C11—C1399.3 (2)
C3—N1—C5—C10−92.8 (2)C7—C6—C11—C1246.0 (2)
C10—C5—C6—C7−1.4 (2)C5—C6—C11—C12−135.40 (19)
N1—C5—C6—C7176.92 (14)C9—C10—C14—C16−27.7 (2)
C10—C5—C6—C11179.97 (15)C5—C10—C14—C16153.41 (16)
N1—C5—C6—C11−1.7 (2)C9—C10—C14—C1597.75 (19)
C5—C6—C7—C8−0.4 (2)C5—C10—C14—C15−81.16 (19)
C11—C6—C7—C8178.25 (17)C1—O2—C17—C18179.70 (16)
C6—C7—C8—C91.7 (3)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N1—H1···O10.89 (1)2.02 (1)2.7402 (18)137 (1)
N1—H1···O1i0.89 (1)2.68 (1)3.3371 (18)132 (1)

Symmetry codes: (i) −x+1, −y, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: GW2075).

References

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  • David, O., Blot, J., Bellec, C., Fargeau-Bellassoued, M. C., Haviari, G., Celerier, J. P., Lhommet, G., Gramain, J. C. & Garadette, D. (1999). J. Org. Chem.64, 3122–3131. [PubMed]
  • Michael, J. P., de Koning, C. B., Gravestock, D., Hosken, G. D., Howard, A. S., Jungmann, C. M., Krause, R. W. M., Parson, A. S., Felly, S. C. & Stanbury, T. V. (1999). Pure Appl. Chem.71, 979–988
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  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
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