(Z)-Ethyl 3-(2,4,6-trimethyl-anilino)but-2-enoate.

The title compound, C(15)H(21)NO(2), was obtained by the reaction of acetoacetate with 2,4,6-trimethyl-aniline using Mexican bentonitic clay as a catalyst. It crystallizes in the enamine form. The β-enamino ester residue is almost perpendicular to the aromatic ring [dihedral angle = 88.10 (6)°]. The mol-ecular conformation is stabilized by a strong intra-molecular N-H⋯O hydrogen bond. In addition, the N-H group forms a weak inter-molecular N-H⋯O hydrogen bond linking the mol-ecules into centrosymmetric dimers.

Related literature

For enamino esters as inter­mediates in the synthesis of natural products, see: Marchand et al. (1994 ▶). β-Enamino esters are useful in synthesis of pharmaceuticals and bioactive heterocycles (Spivey et al., 2003 ▶) and as precursors for the preparation of anti­bacterial, anti­convulsant (Michael et al., 2001 ▶), anti-inflamatory and anti­tumour agents. For the functionalization of these compounds by the introduction of different substituents on the nitro­gen, α-carbon and β-carbonylic carbon atoms, see: Braibante et al. (2002 ▶).

Experimental

Crystal data

C15H21NO2

M = 247.33

Monoclinic,

a = 8.5647 (8) Å

b = 20.6131 (19) Å

c = 8.2404 (8) Å

β = 93.976 (2)°

V = 1451.3 (2) Å3

Z = 4

Mo Kα radiation

μ = 0.07 mm−1

T = 298 K

0.48 × 0.37 × 0.15 mm

Data collection

Bruker SMART APEX CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 1999 ▶) T min = 0.970, T max = 0.989

11717 measured reflections

2634 independent reflections

2160 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.049

wR(F 2) = 0.145

S = 1.05

2634 reflections

166 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.19 e Å−3

Δρmin = −0.21 e Å−3

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

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680903949X/bt5072sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053680903949X/bt5072Isup2.hkl

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

C15H21NO2	F(000) = 536
Mr = 247.33	Dx = 1.132 Mg m−3
Monoclinic, P21/c	Melting point: 338.2 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 8.5647 (8) Å	Cell parameters from 5426 reflections
b = 20.6131 (19) Å	θ = 2.6–25.3°
c = 8.2404 (8) Å	µ = 0.07 mm−1
β = 93.976 (2)°	T = 298 K
V = 1451.3 (2) Å3	Plates, colorless
Z = 4	0.48 × 0.37 × 0.15 mm

Bruker SMART APEX CCD diffractometer	2634 independent reflections
Radiation source: fine-focus sealed tube	2160 reflections with I > 2σ(I)
graphite	Rint = 0.028
Detector resolution: 0.661 pixels mm-1	θmax = 25.4°, θmin = 2.0°
ω scans	h = −10→10
Absorption correction: multi-scan (SADABS; Bruker, 1999)	k = −24→24
Tmin = 0.970, Tmax = 0.989	l = −9→9
11717 measured reflections

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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.145	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ2(Fo2) + (0.0824P)2 + 0.188P] where P = (Fo2 + 2Fc2)/3
2634 reflections	(Δ/σ)max < 0.001
166 parameters	Δρmax = 0.19 e Å−3
0 restraints	Δρmin = −0.21 e Å−3

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.

	x	y	z	Uiso*/Ueq
O1	0.34094 (14)	0.02629 (6)	0.57044 (15)	0.0678 (4)
O2	0.12297 (13)	0.06508 (5)	0.67115 (14)	0.0634 (3)
N1	0.48468 (17)	0.11091 (7)	0.36990 (19)	0.0608 (4)
H1	0.475 (2)	0.0741 (10)	0.407 (2)	0.073*
C1	0.25234 (18)	0.07166 (8)	0.58833 (18)	0.0531 (4)
C2	0.26799 (18)	0.13592 (8)	0.5250 (2)	0.0572 (4)
H2	0.1988	0.1676	0.5560	0.069*
C3	0.37828 (18)	0.15303 (8)	0.4223 (2)	0.0559 (4)
C4	0.3850 (2)	0.22125 (9)	0.3585 (3)	0.0767 (6)
H4A	0.4923	0.2344	0.3555	0.115*
H4B	0.3321	0.2499	0.4285	0.115*
H4C	0.3349	0.2230	0.2507	0.115*
C5	0.0901 (2)	0.00058 (9)	0.7287 (3)	0.0746 (5)
H5A	0.1642	−0.0108	0.8185	0.089*
H5B	0.0998	−0.0307	0.6421	0.089*
C6	−0.0711 (2)	−0.00040 (10)	0.7828 (2)	0.0733 (5)
H6A	−0.0964	−0.0435	0.8164	0.110*
H6B	−0.1433	0.0128	0.6946	0.110*
H6C	−0.0782	0.0289	0.8725	0.110*
C7	0.60799 (18)	0.12825 (7)	0.27088 (19)	0.0520 (4)
C8	0.58802 (19)	0.12037 (8)	0.1023 (2)	0.0568 (4)
C9	0.7112 (2)	0.13715 (8)	0.0097 (2)	0.0603 (4)
H9	0.6984	0.1328	−0.1027	0.072*
C10	0.85176 (19)	0.16000 (8)	0.0787 (2)	0.0568 (4)
C11	0.86788 (19)	0.16666 (8)	0.2457 (2)	0.0577 (4)
H11	0.9623	0.1819	0.2938	0.069*
C12	0.74836 (19)	0.15143 (7)	0.34424 (19)	0.0549 (4)
C13	0.4379 (2)	0.09401 (11)	0.0225 (3)	0.0857 (6)
H13A	0.4511	0.0857	−0.0903	0.129*
H13B	0.3556	0.1251	0.0319	0.129*
H13C	0.4112	0.0544	0.0752	0.129*
C14	0.9846 (2)	0.17663 (10)	−0.0250 (3)	0.0794 (6)
H14A	1.0610	0.2021	0.0375	0.119*
H14B	0.9449	0.2010	−0.1182	0.119*
H14C	1.0322	0.1374	−0.0603	0.119*
C15	0.7719 (3)	0.15816 (11)	0.5262 (2)	0.0779 (6)
H15A	0.8812	0.1640	0.5567	0.117*
H15B	0.7350	0.1197	0.5771	0.117*
H15C	0.7146	0.1951	0.5608	0.117*

	U11	U22	U33	U12	U13	U23
O1	0.0634 (7)	0.0594 (7)	0.0838 (8)	0.0124 (6)	0.0279 (6)	0.0107 (6)
O2	0.0624 (7)	0.0567 (7)	0.0746 (7)	0.0074 (5)	0.0297 (6)	0.0078 (5)
N1	0.0599 (8)	0.0490 (8)	0.0766 (9)	0.0057 (6)	0.0279 (7)	0.0094 (6)
C1	0.0497 (8)	0.0573 (9)	0.0535 (8)	0.0036 (7)	0.0120 (7)	−0.0022 (6)
C2	0.0530 (9)	0.0534 (9)	0.0672 (10)	0.0071 (7)	0.0176 (7)	−0.0019 (7)
C3	0.0543 (9)	0.0506 (8)	0.0639 (9)	0.0035 (7)	0.0119 (7)	0.0002 (7)
C4	0.0776 (12)	0.0550 (10)	0.1014 (14)	0.0119 (9)	0.0333 (11)	0.0115 (9)
C5	0.0786 (12)	0.0627 (11)	0.0861 (12)	0.0072 (9)	0.0319 (10)	0.0177 (9)
C6	0.0698 (12)	0.0707 (11)	0.0814 (12)	−0.0063 (9)	0.0192 (9)	0.0079 (9)
C7	0.0514 (9)	0.0451 (8)	0.0610 (9)	0.0051 (6)	0.0156 (7)	0.0047 (6)
C8	0.0527 (9)	0.0570 (9)	0.0610 (9)	0.0046 (7)	0.0056 (7)	−0.0013 (7)
C9	0.0667 (10)	0.0639 (10)	0.0510 (8)	0.0071 (8)	0.0102 (7)	0.0015 (7)
C10	0.0594 (10)	0.0492 (8)	0.0636 (9)	0.0036 (7)	0.0186 (7)	0.0058 (7)
C11	0.0534 (9)	0.0518 (9)	0.0683 (10)	−0.0035 (7)	0.0079 (7)	0.0008 (7)
C12	0.0610 (10)	0.0492 (8)	0.0552 (9)	0.0056 (7)	0.0081 (7)	0.0026 (6)
C13	0.0639 (12)	0.1009 (16)	0.0914 (14)	−0.0044 (10)	−0.0012 (10)	−0.0153 (12)
C14	0.0781 (13)	0.0738 (12)	0.0907 (14)	−0.0036 (10)	0.0375 (11)	0.0090 (10)
C15	0.0872 (14)	0.0882 (14)	0.0583 (10)	0.0039 (11)	0.0061 (9)	−0.0009 (9)

O1—C1	1.2196 (18)	C7—C8	1.397 (2)
O2—C1	1.3479 (18)	C8—C9	1.388 (2)
O2—C5	1.446 (2)	C8—C13	1.505 (3)
N1—C3	1.351 (2)	C9—C10	1.378 (2)
N1—C7	1.4243 (19)	C9—H9	0.9300
N1—H1	0.82 (2)	C10—C11	1.380 (2)
C1—C2	1.433 (2)	C10—C14	1.509 (2)
C2—C3	1.358 (2)	C11—C12	1.386 (2)
C2—H2	0.9300	C11—H11	0.9300
C3—C4	1.504 (2)	C12—C15	1.506 (2)
C4—H4A	0.9600	C13—H13A	0.9600
C4—H4B	0.9600	C13—H13B	0.9600
C4—H4C	0.9600	C13—H13C	0.9600
C5—C6	1.481 (3)	C14—H14A	0.9600
C5—H5A	0.9700	C14—H14B	0.9600
C5—H5B	0.9700	C14—H14C	0.9600
C6—H6A	0.9600	C15—H15A	0.9600
C6—H6B	0.9600	C15—H15B	0.9600
C6—H6C	0.9600	C15—H15C	0.9600
C7—C12	1.392 (2)
C1—O2—C5	116.36 (12)	C9—C8—C7	118.18 (15)
C3—N1—C7	124.42 (14)	C9—C8—C13	120.59 (16)
C3—N1—H1	112.7 (13)	C7—C8—C13	121.23 (16)
C7—N1—H1	122.8 (13)	C10—C9—C8	122.28 (15)
O1—C1—O2	121.62 (14)	C10—C9—H9	118.9
O1—C1—C2	126.15 (14)	C8—C9—H9	118.9
O2—C1—C2	112.22 (13)	C9—C10—C11	117.98 (15)
C3—C2—C1	123.61 (14)	C9—C10—C14	121.04 (16)
C3—C2—H2	118.2	C11—C10—C14	120.98 (17)
C1—C2—H2	118.2	C10—C11—C12	122.32 (15)
N1—C3—C2	123.10 (15)	C10—C11—H11	118.8
N1—C3—C4	116.49 (15)	C12—C11—H11	118.8
C2—C3—C4	120.40 (14)	C11—C12—C7	118.29 (15)
C3—C4—H4A	109.5	C11—C12—C15	120.61 (16)
C3—C4—H4B	109.5	C7—C12—C15	121.08 (15)
H4A—C4—H4B	109.5	C8—C13—H13A	109.5
C3—C4—H4C	109.5	C8—C13—H13B	109.5
H4A—C4—H4C	109.5	H13A—C13—H13B	109.5
H4B—C4—H4C	109.5	C8—C13—H13C	109.5
O2—C5—C6	108.55 (15)	H13A—C13—H13C	109.5
O2—C5—H5A	110.0	H13B—C13—H13C	109.5
C6—C5—H5A	110.0	C10—C14—H14A	109.5
O2—C5—H5B	110.0	C10—C14—H14B	109.5
C6—C5—H5B	110.0	H14A—C14—H14B	109.5
H5A—C5—H5B	108.4	C10—C14—H14C	109.5
C5—C6—H6A	109.5	H14A—C14—H14C	109.5
C5—C6—H6B	109.5	H14B—C14—H14C	109.5
H6A—C6—H6B	109.5	C12—C15—H15A	109.5
C5—C6—H6C	109.5	C12—C15—H15B	109.5
H6A—C6—H6C	109.5	H15A—C15—H15B	109.5
H6B—C6—H6C	109.5	C12—C15—H15C	109.5
C12—C7—C8	120.94 (14)	H15A—C15—H15C	109.5
C12—C7—N1	119.32 (14)	H15B—C15—H15C	109.5
C8—C7—N1	119.73 (14)
C5—O2—C1—O1	−3.7 (2)	N1—C7—C8—C13	0.2 (2)
C5—O2—C1—C2	175.22 (15)	C7—C8—C9—C10	1.2 (2)
O1—C1—C2—C3	6.4 (3)	C13—C8—C9—C10	−178.42 (17)
O2—C1—C2—C3	−172.41 (15)	C8—C9—C10—C11	−0.6 (2)
C7—N1—C3—C2	−175.71 (16)	C8—C9—C10—C14	178.82 (16)
C7—N1—C3—C4	5.4 (3)	C9—C10—C11—C12	−0.2 (2)
C1—C2—C3—N1	−0.1 (3)	C14—C10—C11—C12	−179.62 (15)
C1—C2—C3—C4	178.75 (17)	C10—C11—C12—C7	0.4 (2)
C1—O2—C5—C6	−167.50 (15)	C10—C11—C12—C15	178.79 (16)
C3—N1—C7—C12	85.6 (2)	C8—C7—C12—C11	0.1 (2)
C3—N1—C7—C8	−95.9 (2)	N1—C7—C12—C11	178.62 (13)
C12—C7—C8—C9	−0.9 (2)	C8—C7—C12—C15	−178.23 (15)
N1—C7—C8—C9	−179.37 (13)	N1—C7—C12—C15	0.2 (2)
C12—C7—C8—C13	178.68 (16)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1	0.82 (2)	2.08 (2)	2.7516 (18)	138.7 (17)
N1—H1···O1i	0.82 (2)	2.60 (2)	3.2201 (18)	133.1 (16)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1	0.82 (2)	2.08 (2)	2.7516 (18)	138.7 (17)
N1—H1⋯O1i	0.82 (2)	2.60 (2)	3.2201 (18)	133.1 (16)

Symmetry code: (i) .