Ethyl (2E)-2-(2H-1,3-benzodioxol-5-yl­methyl­idene)-4-chloro-3-oxobutano­ate

Julio Zukerman-Schpector; Siti Nadiah Abd Salim; Paulo J S Moran; Bruno R S de Paula; J Augusto R Rodrigues; Edward R T Tiekink

doi:10.1107/S1600536811011780

. 2011 Apr 7;67(Pt 5):o1044. doi: 10.1107/S1600536811011780

Ethyl (2E)-2-(2H-1,3-benzodioxol-5-ylmethylidene)-4-chloro-3-oxobutanoate

Julio Zukerman-Schpector ^a,^*, Siti Nadiah Abd Salim ^b, Paulo J S Moran ^c, Bruno R S de Paula ^c, J Augusto R Rodrigues ^c, Edward R T Tiekink ^b

PMCID: PMC3089165 PMID: 21754371

Abstract

In the title compound, C₁₄H₁₃ClO₅, the five-membered ring is in an envelope conformation with the methylene C-atom being the flap. The conformation about the C=C double bond [1.341 (2) Å] is E. The chloropropan-2-one residue is approximately orthogonal to the remaining molecule [dihedral angle = 88.03 (6)°]. In the crystal, the molecules associate via C—H⋯O interactions, involving both carbonyl-O atoms, giving rise to an undulating two-dimensional array in the ac plane.

Related literature

For background to the study, see: Rodrigues et al. (2004 ▶). For ring conformational analysis, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₄H₁₃ClO₅
M _r = 296.69
Orthorhombic,
a = 4.8042 (1) Å
b = 14.9134 (4) Å
c = 18.4793 (5) Å
V = 1323.99 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.31 mm⁻¹
T = 100 K
0.28 × 0.07 × 0.06 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.636, T _max = 0.746
13030 measured reflections
3200 independent reflections
2915 reflections with I > 2σ(I)
R _int = 0.041

Refinement

R[F ² > 2σ(F ²)] = 0.031
wR(F ²) = 0.073
S = 1.05
3200 reflections
182 parameters
H-atom parameters constrained
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.18 e Å⁻³
Absolute structure: Flack (1983 ▶), 1312 Friedel pairs
Flack parameter: −0.03 (5)

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: MarvinSketch (Chemaxon, 2010 ▶) and publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811011780/hg5017sup1.cif

e-67-o1044-sup1.cif^{(18.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811011780/hg5017Isup2.hkl

e-67-o1044-Isup2.hkl^{(153.8KB, hkl)}

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1a⋯O4ⁱ	0.97	2.50	3.348 (2)	146
C11—H11b⋯O3ⁱⁱ	0.97	2.36	3.1585 (18)	139

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

We thank the Brazilian agencies CNPq (306532/2009–3,to JZ-S), CAPES and FAPESP for financial support. The University of Malaya is thanked for support of the crystallographic facility.

supplementary crystallographic information

Comment

As part of the continuing interest in the bio-reduction of α-haloketones and enones (Rodrigues et al., 2004) the title compound, ethyl (2E)-2-(2H-1,3-benzodioxol-5-ylmethylidene)-4- chloro-3-oxobutanoate, (I), was synthesized by means of a Knoevenagel condensation reaction between ethyl 4-chloroacetoacetate and piperonal, affording a mixture of E and Z isomers that were separated by column chromatography (hexane/ethyl acetate, gradient from pure hexane to 95% hexane/5% ethyl acetate).

The conformation of the five-membered ring in (I) is an envelope with the methylene-C1 atom being the flap. This is quantified by the ring puckering parameters Q(2) = 0.1016 (14) Å and φ₂ = 38.4 (8) ° (Cremer & Pople, 1975). The conformation about the C8═C9 double bond [1.341 (2) Å] is E. With the exception of the chloropropan-2-one residue which projects to one side of the molecule, (I) is approximately flat. The major twist in the molecule occurs around the C5—C8 bond as seen in the value of the C4—C5—C8—C9 torsion angle of 165.21 (16) °. The carbonyl and chlorido atoms of the chloropropan-2-one residue lie in a plane with the C₃ backbone. This plane is orthogonal to the main residue with the dihedral angle between the least-squares plane through the O3,C9—C11,Cl1 atoms and that through the C8,C9,C12 atoms being 88.03 (6) °. Both heteroatoms project away from the main residue.

The two most prominent interactions operating in the crystal structure are of the type C—H···O, Table 1. The shortest interaction occurs between symmetry related carbonyl-O and methylene-H atoms of the chloropropan-2-one residues leading to a chain along the a direction. The other C—H···O interaction occurs between the ester-carbonyl-O and the methylene-H of the benzodioxole residue. Overall, the resulting supramolecular architecture is a 2-D array in the ac plane, Fig. 2. The topology is undulating as seen from Fig. 3.

Experimental

The title compound, (I), was prepared by means of a Knoevenagel condensation reaction between ethyl 4-chloroacetoacetate and piperonal. Morpholine (17.4 mg, 0.2 mmol), glacial acetic acid (12.0 mg, 0.2 mmol) and piperonal (300 mg, 2 mmol) were added to [Bmim][NTf₂] (1 ml) in a 10 ml round-bottom flask. The mixture was stirred for 10 min., and then ethyl 4-chloroacetoacetate (395 mg, 2.4 mmol) and 4 Å molecular sieves (360 mg) were added to reaction mixture. After 1.5 h, the ionic liquid layer was extracted with diethyl ether (3 x 5 ml), the ether was evaporated to afford a mixture of E and Z isomers that were separated by column chromatography (hexane/ethyl acetate, gradient from pure hexane to 95% hexane/5% ethyl acetate). The crystallized isomer, obtained by slow evaporation from a dichloromethane/hexane mixture, was shown by crystallography to be the E isomer; M.pt. 367.1–367.4 K.