(2Z,2'Z)-Diethyl 3,3'-[butane-1,4-diylbis(aza-nedi-yl)]bis-(but-2-enoate).

The whole mol-ecule of the title β-enamino-ester, C(16)H(28)N(2)O(4), is generated by a crystallographic inversion center, situated at the mid-point of the central C-C bond of the 1,4-diamino-butane segment. There are two intra-molecular N-H⋯O hydrogen bonds that generate S(6) ring motifs. This leads to the Z conformation about the C=C bonds [1.3756 (17) Å]. The mol-ecule is S-shaped with the planar central 1,4-diamino-butane segment [maximum deviation for non H-atoms = 0.0058 (13) Å] being inclined to the ethyl butyl-enonate fragment [C-C-O-C-C=C-C; maximum deviation = 0.0710 (12) Å] by 15.56 (10)°. In the crystal, mol-ecules are linked via C-H⋯O inter-actions, leading to the formation of an undulating two-dimensional network lying parallel to the bc plane.

Related literature

For general background to the use of β-enamino esters as precursors in organic synthesis, see: Eddington et al. (2000 ▶); Palmieri & Cimarelli (1996 ▶); Zhang & Hu (2006 ▶). For the synthesis of β-enamino esters, see: Harrad et al. (2010 ▶); Hegde & Jones (1993 ▶); Lue & Greenhill (1997 ▶); Katritzky et al. (2004 ▶); Bartoli et al. (1995 ▶); Reddy et al. (2005 ▶). For the structure of related compounds, see: Harrad et al. (2011a ▶,b ▶); Amézquita-Valencia et al. (2009 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C16H28N2O4

M = 312.40

Monoclinic,

a = 5.7624 (5) Å

b = 13.1329 (8) Å

c = 11.7601 (9) Å

β = 98.547 (6)°

V = 880.09 (12) Å3

Z = 2

Mo Kα radiation

μ = 0.08 mm−1

T = 133 K

0.45 × 0.40 × 0.30 mm

Data collection

Stoe IPDS 2 diffractometer

Absorption correction: multi-scan (MULscanABS in PLATON; Spek, 2009 ▶) T min = 0.679, T max = 1.000

9379 measured reflections

1661 independent reflections

1392 reflections with I > 2σ(I)

R int = 0.052

Refinement

R[F 2 > 2σ(F 2)] = 0.035

wR(F 2) = 0.081

S = 1.04

1661 reflections

107 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.15 e Å−3

Δρmin = −0.14 e Å−3

Data collection: X-AREA (Stoe & Cie, 2009 ▶); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2009 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶) and Mercury (Macrae et al., 2008 ▶); software used to prepare material for publication: SHELXL97, PLATON and publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812036823/ds2210sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812036823/ds2210Isup2.hkl

Supplementary material file. DOI: 10.1107/S1600536812036823/ds2210Isup3.cml

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

C16H28N2O4	F(000) = 340
Mr = 312.40	Dx = 1.179 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 8450 reflections
a = 5.7624 (5) Å	θ = 2.3–26.2°
b = 13.1329 (8) Å	µ = 0.08 mm−1
c = 11.7601 (9) Å	T = 133 K
β = 98.547 (6)°	Block, colourless
V = 880.09 (12) Å3	0.45 × 0.40 × 0.30 mm
Z = 2

Stoe IPDS 2 diffractometer	1661 independent reflections
Radiation source: fine-focus sealed tube	1392 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.052
φ + ω scans	θmax = 25.7°, θmin = 2.3°
Absorption correction: multi-scan (MULscanABS in PLATON; Spek, 2009)	h = −7→7
Tmin = 0.679, Tmax = 1.000	k = −14→15
9379 measured reflections	l = −14→14

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.035	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.081	w = 1/[σ2(Fo2) + (0.0346P)2 + 0.1872P] where P = (Fo2 + 2Fc2)/3
S = 1.04	(Δ/σ)max < 0.001
1661 reflections	Δρmax = 0.15 e Å−3
107 parameters	Δρmin = −0.14 e Å−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.015 (4)

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. The NH H-atom was located in a difference electron-density map and freely refined. The C-bound H-atoms were included in calculated positions and treated as riding atoms: C—H = 0.95, 0.99 and 0.98, Å for CH(allyl), CH2 and CH3 H-atoms, respectively, with Uiso(H) = k × Ueq(parent C-atom), where k = 1.5 for CH3 H-atoms and = 1.2 for other H atoms.

	x	y	z	Uiso*/Ueq
O1	0.93675 (15)	0.33513 (7)	0.19771 (7)	0.0277 (3)
O2	0.72096 (15)	0.23004 (7)	0.07166 (7)	0.0282 (3)
N1	0.37954 (19)	0.12458 (8)	0.15569 (9)	0.0252 (3)
C1	1.2379 (2)	0.44490 (11)	0.15191 (13)	0.0358 (4)
C2	1.0631 (2)	0.36486 (10)	0.10551 (12)	0.0312 (4)
C3	0.7649 (2)	0.26399 (9)	0.17015 (10)	0.0231 (3)
C4	0.6507 (2)	0.23715 (9)	0.26565 (10)	0.0237 (3)
C5	0.4629 (2)	0.17140 (9)	0.25516 (10)	0.0231 (3)
C6	0.1806 (2)	0.05468 (10)	0.13799 (11)	0.0274 (4)
C7	0.1049 (2)	0.03591 (10)	0.01049 (11)	0.0277 (4)
C8	0.3384 (2)	0.15152 (11)	0.35620 (11)	0.0299 (4)
H1A	1.15460	0.50510	0.17410	0.0540*
H1B	1.33290	0.46370	0.09260	0.0540*
H1C	1.34010	0.41820	0.21930	0.0540*
H1N	0.458 (3)	0.1381 (11)	0.0988 (13)	0.033 (4)*
H2A	0.95300	0.39230	0.04010	0.0370*
H2B	1.14480	0.30530	0.07830	0.0370*
H4	0.70620	0.26570	0.33890	0.0280*
H6A	0.04810	0.08390	0.17190	0.0330*
H6B	0.22510	−0.01070	0.17720	0.0330*
H7A	0.23740	0.00610	−0.02300	0.0330*
H7B	0.06300	0.10160	−0.02860	0.0330*
H8A	0.32040	0.07790	0.36570	0.0450*
H8B	0.18330	0.18370	0.34310	0.0450*
H8C	0.43020	0.17990	0.42580	0.0450*

	U11	U22	U33	U12	U13	U23
O1	0.0308 (5)	0.0273 (5)	0.0257 (5)	−0.0067 (4)	0.0069 (4)	−0.0027 (4)
O2	0.0339 (5)	0.0306 (5)	0.0198 (4)	−0.0040 (4)	0.0030 (4)	−0.0016 (4)
N1	0.0257 (6)	0.0282 (6)	0.0215 (5)	−0.0047 (4)	0.0026 (4)	−0.0014 (4)
C1	0.0339 (7)	0.0320 (8)	0.0439 (8)	−0.0050 (6)	0.0133 (6)	−0.0005 (6)
C2	0.0361 (7)	0.0287 (7)	0.0305 (7)	−0.0037 (6)	0.0110 (6)	0.0022 (5)
C3	0.0240 (6)	0.0198 (6)	0.0242 (6)	0.0023 (5)	−0.0002 (5)	−0.0004 (5)
C4	0.0262 (6)	0.0251 (6)	0.0191 (6)	−0.0005 (5)	0.0008 (5)	−0.0028 (5)
C5	0.0242 (6)	0.0232 (6)	0.0211 (6)	0.0044 (5)	0.0006 (5)	0.0007 (5)
C6	0.0270 (6)	0.0273 (7)	0.0266 (7)	−0.0049 (5)	−0.0002 (5)	0.0000 (5)
C7	0.0280 (6)	0.0275 (7)	0.0269 (7)	−0.0034 (5)	0.0016 (5)	−0.0034 (5)
C8	0.0277 (7)	0.0375 (7)	0.0242 (7)	−0.0025 (6)	0.0033 (5)	−0.0004 (5)

O1—C2	1.4467 (16)	C1—H1B	0.9800
O1—C3	1.3650 (15)	C1—H1C	0.9800
O2—C3	1.2318 (14)	C2—H2A	0.9900
N1—C5	1.3454 (16)	C2—H2B	0.9900
N1—C6	1.4592 (16)	C4—H4	0.9500
N1—H1N	0.880 (16)	C6—H6A	0.9900
C1—C2	1.5013 (19)	C6—H6B	0.9900
C3—C4	1.4277 (17)	C7—H7A	0.9900
C4—C5	1.3756 (17)	C7—H7B	0.9900
C5—C8	1.4994 (17)	C8—H8A	0.9800
C6—C7	1.5182 (18)	C8—H8B	0.9800
C7—C7i	1.5243 (17)	C8—H8C	0.9800
C1—H1A	0.9800
C2—O1—C3	115.78 (9)	C1—C2—H2A	110.00
C5—N1—C6	125.66 (11)	C1—C2—H2B	110.00
C5—N1—H1N	114.3 (10)	H2A—C2—H2B	108.00
C6—N1—H1N	120.0 (10)	C3—C4—H4	119.00
O1—C2—C1	107.56 (11)	C5—C4—H4	119.00
O1—C3—C4	112.65 (10)	N1—C6—H6A	110.00
O1—C3—O2	120.77 (10)	N1—C6—H6B	110.00
O2—C3—C4	126.58 (11)	C7—C6—H6A	110.00
C3—C4—C5	122.20 (11)	C7—C6—H6B	110.00
N1—C5—C8	117.28 (11)	H6A—C6—H6B	108.00
N1—C5—C4	122.64 (11)	C6—C7—H7A	109.00
C4—C5—C8	120.06 (11)	C6—C7—H7B	109.00
N1—C6—C7	110.33 (10)	H7A—C7—H7B	108.00
C6—C7—C7i	111.40 (10)	C7i—C7—H7A	109.00
C2—C1—H1A	109.00	C7i—C7—H7B	109.00
C2—C1—H1B	109.00	C5—C8—H8A	109.00
C2—C1—H1C	109.00	C5—C8—H8B	109.00
H1A—C1—H1B	109.00	C5—C8—H8C	109.00
H1A—C1—H1C	109.00	H8A—C8—H8B	109.00
H1B—C1—H1C	109.00	H8A—C8—H8C	109.00
O1—C2—H2A	110.00	H8B—C8—H8C	110.00
O1—C2—H2B	110.00
C3—O1—C2—C1	178.47 (10)	O1—C3—C4—C5	176.01 (11)
C2—O1—C3—O2	−1.34 (16)	O2—C3—C4—C5	−3.6 (2)
C2—O1—C3—C4	179.00 (10)	C3—C4—C5—N1	2.77 (19)
C6—N1—C5—C4	−179.53 (11)	C3—C4—C5—C8	−175.62 (11)
C6—N1—C5—C8	−1.09 (18)	N1—C6—C7—C7i	−179.28 (10)
C5—N1—C6—C7	167.36 (11)	C6—C7—C7i—C6i	179.97 (16)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O2	0.880 (16)	2.000 (16)	2.7099 (14)	136.9 (13)
C8—H8C···O2ii	0.98	2.51	3.4697 (16)	167

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1N⋯O2	0.880 (16)	2.000 (16)	2.7099 (14)	136.9 (13)
C8—H8C⋯O2i	0.98	2.51	3.4697 (16)	167

Symmetry code: (i) .