4-(3-Methoxy­phen­yl)-2,6-dimethyl­cyclo­hex-3-enecarboxylic acid

Songwen Xie; Dannette A Nusbaum; Holly J Stein; Maren Pink

doi:10.1107/S1600536810018544

. 2010 May 26;66(Pt 6):o1443. doi: 10.1107/S1600536810018544

4-(3-Methoxyphenyl)-2,6-dimethylcyclohex-3-enecarboxylic acid

Songwen Xie ^a,^*, Dannette A Nusbaum ^a, Holly J Stein ^a, Maren Pink ^b

PMCID: PMC2979377 PMID: 21579516

Abstract

The racemic title compound, C₁₆H₂₀O₃, was synthesized to study the hydrogen-bonding interaction of the two enantiomers in the solid state. In the crystal structure, R and S pairs of the racemate are linked by pairs of intermolecular O—H⋯O hydrogen bonds, producing centrosymmetric R ₂ ²(8) rings.

Related literature

For similar compounds in which the racemates also consist of carboxylic acid RS dimers, see: Xie et al. (2002 ▶, 2007a ▶, 2008a ▶,b ▶). For the structure of the precursor of the title compound, which is achiral and forms hydrogen-bonded dimers, see: Xie et al. (2007b ▶). The chirality of the title compound is solely generated by the presence of the double bond in the cyclohexene ring, see: Xie et al. (2004 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₆H₂₀O₃
M _r = 260.32
Orthorhombic,
a = 11.032 (2) Å
b = 7.8423 (17) Å
c = 32.140 (8) Å
V = 2780.7 (11) Å³
Z = 8
Synchrotron radiation
λ = 0.44280 Å
μ = 0.05 mm⁻¹
T = 100 K
0.02 × 0.01 × 0.01 mm

Data collection

Bruker Platform goniometer diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶; Blessing, 1995 ▶) T _min = 0.999, T _max = 1.000
8586 measured reflections
2173 independent reflections
1755 reflections with I > 2σ(I)
R _int = 0.050

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.119
S = 1.11
2173 reflections
179 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810018544/fj2304sup1.cif

e-66-o1443-sup1.cif^{(18.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810018544/fj2304Isup2.hkl

e-66-o1443-Isup2.hkl^{(106.9KB, 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
O2—H2O⋯O1ⁱ	0.94 (3)	1.71 (3)	2.6523 (19)	175 (2)

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Symmetry code: (i) Inline graphic .

Acknowledgments

SX, DN, and HS are grateful for the Grant-in-aid for Faculty Research from Indiana University Kokomo, as well as the Senior Research Grant from Indiana Academy of Science. ChemMatCARS Sector 15 is principally supported by the National Science Foundation/Department of Energy under grant No. CHE-0535644. Use of the advanced Photon Source was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE—AC02-06CH11357. The authors also want to thank the beamline for synchrotron radiation at the Advanced Photon Source, Argonne National Laboratory.

supplementary crystallographic information

Comment

The title carboxylic acid was prepared to study the interaction of the two enantiomers in the solid state. We have previously reported the structure of its precursor, which is achiral and forms hydrogen-bonded dimers (Xie et al., 2007b). The chirality of the title compound is solely generated by the presence of the double bond in the cyclohexene ring (Xie et al., 2004). The resultant racemate is made up of carboxylic acid RS dimers (Xie et al., 2002, 2007a, 2008a,b). The structure and atom numbering are shown in Fig. 1, which illustrates the half-chair conformation of the cyclohexene ring. The torsion angles involving atoms C4, C5, C6, C1, and C2 are near 180°. The carboxyl group is almost perpendicular to the cyclohexene ring with an angle of 85.3° between the O1—C14—O2—C3 plane and the C1—C6 ring. The double bond between C5—C6 is not fully conjugated with the aromatic ring as shown by the C1—C6—C5 plane to benzene ring angle of 38.7°. Unlike other previously reported para substituted analogs and like other previously reported meta substituted analogs (Xie et al., 2008b), the molecule also has a chiral axis due to the meta methoxy substituent on the aromatic ring.

Fig. 2 shows the hydrogen bonding scheme. Atom O2 acts as a donor in an intermolecular hydrogen bond to atom O1, producing an R22(8) ring (Bernstein et al., 1995), thus creating a hydrogen- bonded dimer. There is no evidence to suggest that weak directional interactions interconnect the dimers. Hydrogen bond geometry is given in Table 1.

Experimental

The title carboxylic acid was synthesized following the similar method reported by Xie et al., 2002. Purified compound was recrystallized from hexane- dichloromethane as colorless plates (m.p. 415-417 K).