Ethyl 6-(4-bromo­phen­yl)-4-(4-fluoro­phen­yl)-2-oxocyclo­hex-3-ene-1-carboxyl­ate

Rajni Kant; Vivek K Gupta; Kamini Kapoor; M Sapnakumari; B Narayana; B K Sarojini

doi:10.1107/S1600536812038202

. 2012 Sep 12;68(Pt 10):o2917–o2918. doi: 10.1107/S1600536812038202

Ethyl 6-(4-bromophenyl)-4-(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate

Rajni Kant ^a,^*, Vivek K Gupta ^a, Kamini Kapoor ^a, M Sapnakumari ^b, B Narayana ^b, B K Sarojini ^c

PMCID: PMC3470264 PMID: 23125708

Abstract

There are two independent molecules in the asymmetric unit of the title compound, C₂₁H₁₈BrFO₃, in which the dihedral angles between the fluorophenyl and bromophenyl groups are 77.0 (1) and 85.8 (1)°. In one of the molecules, two methine C—H groups of the cyclohexene ring are disordered over two sets of sites in a 0.53 (2):0.47 (2) ratio. In both molecules, the atoms of the ethyl group were refined as disordered over two sets of sites with occupancies of 0.67 (2):0.33 (2) and 0.63 (4):0.37 (4). The cyclohexene rings have slightly distorted sofa conformations in both molecules. In the crystal, C—H⋯O interactions link molecules into chains along the b axis.

Related literature

For background to the synthesis, see: Sreevidya et al. (2010 ▶); Padmavathi et al. (2000 ▶); Senguttuvan & Nagarajan (2010 ▶); Butcher et al. (2011 ▶). For related structures, see: Dutkiewicz et al. (2011a ▶,b ▶,c ▶); Fun et al. (2010 ▶); Harrison et al. (2010 ▶). For ring conformations, see: Duax & Norton (1975 ▶).

Experimental

Crystal data

C₂₁H₁₈BrFO₃
M _r = 417.26
Triclinic,
a = 11.8886 (5) Å
b = 13.3481 (5) Å
c = 13.4128 (5) Å
α = 77.214 (3)°
β = 66.757 (4)°
γ = 87.856 (3)°
V = 1904.27 (13) Å³
Z = 4
Mo Kα radiation
μ = 2.19 mm⁻¹
T = 293 K
0.3 × 0.2 × 0.2 mm

Data collection

Oxford Diffraction Xcalibur Sapphire3 diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010 ▶) T _min = 0.816, T _max = 1.000
27878 measured reflections
7484 independent reflections
4086 reflections with I > 2σ(I)
R _int = 0.049

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.139
S = 1.02
7484 reflections
526 parameters
8 restraints
H-atom parameters constrained
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.52 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812038202/gk2518sup1.cif

e-68-o2917-sup1.cif^{(48.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812038202/gk2518Isup2.hkl

e-68-o2917-Isup2.hkl^{(358.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812038202/gk2518Isup3.cml

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
C5A—H5A1⋯O1B ⁱ	0.97	2.58	3.388 (5)	141
C14A—H14A⋯O1B ⁱ	0.93	2.58	3.445 (6)	154
C5B—H5B1⋯O1A ⁱⁱ	0.97	2.55	3.351 (4)	140
C5B—H5B2⋯O2A ⁱⁱⁱ	0.97	2.59	3.457 (5)	149

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

Acknowledgments

RK acknowledges the Department of Science & Technology for access to the single-crystal X-ray diffractometer sanctioned as a National Facility under project No. SR/S2/CMP-47/2003. BN thanks the UGC for financial assistance through the BSR one-time grant for the purchase of chemicals. MS thanks the DST for providing financial help for the research work through an INSPIRE Fellowship.

supplementary crystallographic information

Comment

Michael addition of ethyl acetoacetate to chalcones yields 4,6-diaryl-2-oxo -cyclohex-3-ene-1-carboxylate derivatives (Sreevidya et al., 2010), which could be used as efficient synthons for building spiro compounds or as intermediates in the synthesis of isoxazoles, pyrazoles and quinazolines (Padmavathi et al., 2000; Senguttuvan & Nagarajan,2010; Butcher et al., 2011). The crystal structure of some cyclohexenone derivatives, viz., methyl 4,6-bis(4-fluorophenyl)-2-oxo cyclohex-3-ene-1-carboxylate (Fun et al., 2010), (1RS,6SR)-ethyl 4-(4-chlorophenyl)-6-(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate toluene hemisolvate (Dutkiewicz et al., 2011a), (1RS,6SR)-ethyl 4,6-bis(4-fluorophenyl)-2-oxocyclohex-3]-ene-1-carboxylate (Dutkiewicz et al., 2011b), (1RS,6SR)-ethyl 4-(2,4-dichlorophenyl)-6-(4-fluorophenyl) -2-oxocyclohex-3-ene-1-carboxylate (Dutkiewicz et al.,2011c) and ethyl 4-(2,4-dichlorophenyl)-6-(6-methoxy-2-naphthyl)-2-oxocyclohex-3-ene-1- carboxylate(Harrison et al., 2010) have been reported. In view of the importance of cyclohexenone derivatives, the title compound (I) was prepared and its crystal structure is reported.

In (I) (Fig. 1), all bond lengths and angles are normal and correspond to those to those observed in the related structures (Dutkiewicz et al., 2011a,b,c; Fun et al., 2010; Harrison et al., 2010). The cyclohexene rings have slightly distorted sofa conformations in both the molecules [asymmetry parameters: ΔCs(C3A—C6A) = 4.11 for molecule A; ΔCs(C2B—C5B) = 4.58 /4.65 for molecule B (Duax & Norton, 1975)]. The fluorophenyl and bromophenyl rings are inclined to each other forming dihedral angles of 77.0 (1)° in molecule A and 85.8 (1)° in molecule B. In molecule B, C1 and C6 are disordered over two sites with a 0.53 (2):0.47 (2) ratio. The atoms of the ethyl group were refined as disordered over two sets of sites with occupancies of 0.67 (2)/0.33 (2) and 0.63 (4)/0.37 (4). In the crystal structure C—H···O hydrogen bonds create chains of molecules along the y direction (Table 1, Fig. 2).

Experimental

(2E)-3-(4-Bromophenyl)-1-(4-fluorophenyl)prop-2-en-1-one (3.05 g, 0.01 mol) and ethyl acetoacetate (1.30 g, 0.01 mol) were refluxed for 8 h in 30 ml absolute alcohol in presence of 10% NaOH. The reaction mixture was cooled to room temperature and the precipitate obtained was filtered. Single crystals were grown by slow evaporation from absolute alcohol (m.p.= 403 K).