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Acta Cryst. (2010). E66, o500    [ doi:10.1107/S1600536810003260 ]

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

M. Amézquita-Valencia, S. Hernández-Ortega, G. A. Suárez-Ortiz and A. Cabrera

Abstract top

The title compound, C18H27NO2, crystallizes as the enamine form with Z geometry. The [beta]-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.

Comment top

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.

Related literature top

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

Experimental top

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 top

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.

Computing details top

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

Figures top
[Figure 1] 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.
[Figure 2] Fig. 2. The centrosymmetric intermolecular N—H···O hydrogen bonding network in dashes lines. symmetry code 1-x, -y, 1-z.
(Z)-Ethyl 3-(2,6-diisopropylanilino)but-2-enoate top
Crystal data top
C18H27NO2Z = 2
Mr = 289.41F(000) = 316
Triclinic, P1Dx = 1.092 Mg m−3
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 mm−1
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 top
Bruker SMART APEX CCD area-detector
diffractometer		1574 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 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)] = 0.041Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.085H atoms treated by a mixture of independent and constrained refinement
S = 0.84 w = 1/[σ2(Fo2) + (0.020P)2]
where P = (Fo2 + 2Fc2)/3
3233 reflections(Δ/σ)max < 0.001
199 parametersΔρmax = 0.11 e Å−3
1 restraintΔρmin = −0.10 e Å−3
Crystal data top
C18H27NO2γ = 101.255 (4)°
Mr = 289.41V = 880.1 (3) Å3
Triclinic, P1Z = 2
a = 8.4750 (17) ÅMo Kα radiation
b = 8.8995 (18) ŵ = 0.07 mm−1
c = 11.956 (2) ÅT = 298 K
α = 94.901 (3)°0.29 × 0.21 × 0.05 mm
β = 91.801 (3)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer		1574 reflections with I > 2σ(I)
7319 measured reflectionsRint = 0.052
3233 independent reflectionsθmax = 25.4°
Refinement top
R[F2 > 2σ(F2)] = 0.041H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.085Δρmax = 0.11 e Å−3
S = 0.84Δρmin = −0.10 e Å−3
3233 reflectionsAbsolute structure: ?
199 parametersFlack parameter: ?
1 restraintRogers parameter: ?
Special details top

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) top
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) top
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, °) top
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, °) top
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.
Table 1
Selected geometric parameters (Å, °) top
O1—C11.2173 (18)N1—C51.4310 (19)
O2—C11.3543 (18)C1—C21.419 (2)
N1—C31.3439 (19)C2—C31.350 (2)
C3—N1—C5125.68 (14)C3—C2—C1124.19 (16)
O1—C1—C2126.24 (17)N1—C3—C2122.83 (15)
Table 2
Hydrogen-bond geometry (Å, °) top
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.
Acknowledgements top

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

references
References top

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