2,6-Dimethyl-4-m-tolyl­cyclo­hex-3-enecarboxylic acid

Xie, S.; Stein, H.J.; Pink, M.

doi:10.1107/S1600536808027542

organic compounds

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ISSN: 2056-9890

Volume 64| Part 10| October 2008| Page o1869

doi:10.1107/S1600536808027542

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2,6-Dimethyl-4-m-tolylcyclohex-3-enecarboxylic acid

Songwen Xie,^a ^* Holly J. Stein ^a and Maren Pink ^b

^aDepartment of Natural Information and Mathematical Sciences, Indiana University Kokomo, Kokomo, IN 46904-9003, USA, and ^bIndiana University Molecular Structure Center, Indiana University, Bloomington, IN 47405-7102, USA
^*Correspondence e-mail: soxie@iuk.edu

(Received 29 July 2008; accepted 27 August 2008; online 6 September 2008)

The title compound, C₁₆H₂₀O₂, was synthesized to study the hydrogen-bonding interaction of the two enantiomers in the solid state. The racemate is made up of carboxylic acid RS dimers. Intermolecular O—H⋯O hydrogen bonds produce centrosymmetric R₂²(8) rings which dimerize the two chiral enantiomers through their carboxyl groups. The chirality of this compound is generated by the presence of the double bond in the cyclohexene ring and a chiral axis due to the meta-methyl substituent on the aromatic ring.

Related literature

In similar compounds previously reported (Xie et al., 2002 , 2007a , 2008 ), the racemates also consist of carboxylic acid RS dimers. For related literature, see: Xie et al. (2007b , 2004 ); Bernstein et al. (1995 ).

Experimental

Crystal data

C₁₆H₂₀O₂
M_r = 244.32
Orthorhombic, P b c a
a = 11.2581 (10) Å
b = 8.1055 (7) Å
c = 29.857 (3) Å
V = 2724.5 (4) Å³
Z = 8
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 150 (2) K
0.20 × 0.18 × 0.05 mm

Data collection

Bruker Kappa APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.985, T_max = 0.996
18515 measured reflections
3120 independent reflections
2265 reflections with I > 2σ(I)
R_int = 0.043

Refinement

R[F² > 2σ(F²)] = 0.049
wR(F²) = 0.136
S = 1.03
3120 reflections
170 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O⋯O2ⁱ	1.05 (3)	1.62 (3)	2.6628 (18)	174 (3)
Symmetry code: (i) -x+1, -y, -z+1.

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.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808027542/om2254sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808027542/om2254Isup2.hkl

checkCIF report

Comment top

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 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, 2008). 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 all near 180°, as are those involving atoms C13, C2, C3, C4, and C15. The carboxyl group is almost perpendicular to the cyclohexene ring with an angle of 86.5° between the O1—C14—O2 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 42.4°. Unlike other previously reported para substituted analogs, the molecule also has a chiral axis due to the meta methyl substituent on the aromatic ring.

Fig. 2 shows the hydrogen bonding scheme. Atom O1 acts as a donor in an intermolecular hydrogen bond to atom O2, 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.

Related literature top

In similar compounds previously reported (Xie et al., 2002, 2007a, 2008), the racemates also consist of carboxylic acid RS dimers. For related literature, see: Xie et al. (2007b, 2004); Bernstein et al. (1995).

Experimental top

The title carboxylic acid was synthesized following the similar method reported by Xie et al., 2002. The purified compound was recrystallized from hexane-dichloromethane as colorless plates (m.p. 412–415 K).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure and atom numbering scheme.
	Fig. 2. Hydrogen bonded dimer. Dashed lines represent hydrogen bonds. [Symmetry code: #1 -x + 1, -y, -z + 1.]

2,6-Dimethyl-4-m-tolylcyclohex-3-enecarboxylic acid top

Crystal data top

C₁₆H₂₀O₂	F(000) = 1056
M_r = 244.32	D_x = 1.191 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 3951 reflections
a = 11.2581 (10) Å	θ = 3.2–25.9°
b = 8.1055 (7) Å	µ = 0.08 mm⁻¹
c = 29.857 (3) Å	T = 150 K
V = 2724.5 (4) Å³	Plate, colorless
Z = 8	0.20 × 0.18 × 0.05 mm

Data collection top

Bruker Kappa APEXII diffractometer	3120 independent reflections
Radiation source: fine-focus sealed tube	2265 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.043
Detector resolution: 8.3 pixels mm^-1	θ_max = 27.5°, θ_min = 1.4°
ω and ϕ scans	h = −14→12
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −10→10
T_min = 0.985, T_max = 0.996	l = −38→36
18515 measured reflections

Refinement top

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) = 0.136	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.066P)² + 0.9686P] where P = (F_o² + 2F_c²)/3
3120 reflections	(Δ/σ)_max < 0.001
170 parameters	Δρ_max = 0.50 e Å⁻³
0 restraints	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₁₆H₂₀O₂	V = 2724.5 (4) Å³
M_r = 244.32	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 11.2581 (10) Å	µ = 0.08 mm⁻¹
b = 8.1055 (7) Å	T = 150 K
c = 29.857 (3) Å	0.20 × 0.18 × 0.05 mm

Data collection top

Bruker Kappa APEXII diffractometer	3120 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2265 reflections with I > 2σ(I)
T_min = 0.985, T_max = 0.996	R_int = 0.043
18515 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	0 restraints
wR(F²) = 0.136	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Δρ_max = 0.50 e Å⁻³
3120 reflections	Δρ_min = −0.20 e Å⁻³
170 parameters

Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
O1	0.47404 (12)	0.21830 (16)	0.50798 (4)	0.0403 (3)
H1O	0.477 (3)	0.103 (4)	0.5238 (11)	0.113 (11)*
O2	0.51225 (11)	0.06571 (15)	0.44750 (4)	0.0362 (3)
C1	0.56818 (15)	0.5618 (2)	0.38758 (6)	0.0333 (4)
H1A	0.5723	0.6504	0.4104	0.040*
H1B	0.6339	0.5799	0.3661	0.040*
C2	0.58687 (14)	0.3953 (2)	0.41086 (6)	0.0308 (4)
H2	0.5978	0.3087	0.3873	0.037*
C3	0.47402 (14)	0.3553 (2)	0.43738 (5)	0.0274 (4)
H3	0.4578	0.4494	0.4582	0.033*
C4	0.36497 (13)	0.3349 (2)	0.40608 (5)	0.0272 (3)
H4	0.3711	0.2262	0.3904	0.033*
C5	0.36254 (14)	0.4705 (2)	0.37130 (6)	0.0309 (4)
H5	0.2923	0.4822	0.3540	0.037*
C6	0.45258 (14)	0.57605 (19)	0.36300 (5)	0.0262 (3)
C7	0.43895 (13)	0.7170 (2)	0.33124 (5)	0.0282 (4)
C8	0.37328 (15)	0.7010 (2)	0.29151 (5)	0.0316 (4)
H8	0.3374	0.5979	0.2846	0.038*
C9	0.35932 (15)	0.8328 (2)	0.26180 (6)	0.0354 (4)
C10	0.41173 (16)	0.9834 (2)	0.27251 (7)	0.0413 (5)
H10	0.4038	1.0740	0.2525	0.050*
C11	0.47524 (17)	1.0027 (2)	0.31192 (7)	0.0421 (5)
H11	0.5088	1.1070	0.3191	0.051*
C12	0.49008 (15)	0.8706 (2)	0.34103 (6)	0.0351 (4)
H12	0.5351	0.8843	0.3677	0.042*
C13	0.69806 (14)	0.4001 (2)	0.43992 (6)	0.0360 (4)
H13A	0.7662	0.4336	0.4216	0.054*
H13B	0.7127	0.2903	0.4525	0.054*
H13C	0.6868	0.4795	0.4643	0.054*
C14	0.48878 (13)	0.2002 (2)	0.46525 (6)	0.0284 (4)
C15	0.25044 (15)	0.3372 (2)	0.43369 (6)	0.0333 (4)
H15A	0.1820	0.3237	0.4137	0.050*
H15B	0.2440	0.4427	0.4496	0.050*
H15C	0.2520	0.2468	0.4555	0.050*
C16	0.2881 (2)	0.8129 (3)	0.21924 (6)	0.0483 (5)
H16A	0.2877	0.6965	0.2103	0.072*
H16B	0.3240	0.8793	0.1954	0.072*
H16C	0.2064	0.8500	0.2244	0.072*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0541 (8)	0.0364 (7)	0.0303 (7)	0.0076 (6)	0.0021 (6)	0.0048 (6)
O2	0.0399 (6)	0.0362 (7)	0.0327 (7)	0.0045 (5)	0.0002 (5)	0.0041 (5)
C1	0.0313 (8)	0.0340 (9)	0.0346 (9)	−0.0030 (7)	0.0007 (7)	0.0049 (7)
C2	0.0261 (8)	0.0334 (9)	0.0330 (9)	−0.0012 (6)	−0.0007 (7)	0.0037 (7)
C3	0.0260 (7)	0.0288 (8)	0.0273 (8)	0.0012 (6)	0.0000 (6)	0.0012 (7)
C4	0.0251 (7)	0.0273 (8)	0.0292 (8)	−0.0019 (6)	−0.0039 (6)	0.0038 (7)
C5	0.0287 (8)	0.0330 (9)	0.0310 (9)	0.0013 (6)	−0.0041 (7)	0.0052 (7)
C6	0.0298 (7)	0.0267 (8)	0.0222 (8)	0.0020 (6)	0.0022 (6)	−0.0003 (6)
C7	0.0275 (7)	0.0306 (8)	0.0264 (8)	0.0031 (6)	0.0068 (6)	0.0046 (7)
C8	0.0346 (8)	0.0319 (9)	0.0282 (8)	0.0042 (7)	0.0046 (7)	0.0032 (7)
C9	0.0339 (8)	0.0419 (10)	0.0305 (9)	0.0081 (7)	0.0059 (7)	0.0096 (8)
C10	0.0366 (9)	0.0398 (10)	0.0474 (11)	0.0026 (8)	0.0077 (8)	0.0184 (9)
C11	0.0384 (9)	0.0328 (9)	0.0551 (12)	−0.0057 (8)	0.0049 (9)	0.0107 (9)
C12	0.0329 (8)	0.0356 (9)	0.0368 (9)	−0.0041 (7)	0.0029 (7)	0.0054 (8)
C13	0.0257 (8)	0.0414 (10)	0.0410 (10)	−0.0020 (7)	−0.0027 (7)	0.0061 (8)
C14	0.0199 (7)	0.0289 (8)	0.0365 (9)	0.0000 (6)	−0.0029 (6)	0.0017 (7)
C15	0.0293 (8)	0.0363 (9)	0.0344 (9)	0.0007 (7)	−0.0020 (7)	0.0023 (7)
C16	0.0602 (12)	0.0509 (12)	0.0338 (10)	0.0090 (10)	−0.0029 (9)	0.0125 (9)

Geometric parameters (Å, º) top

O1—C14	1.295 (2)	C7—C8	1.404 (2)
O1—H1O	1.05 (3)	C8—C9	1.398 (2)
O2—C14	1.241 (2)	C8—H8	0.9500
C1—C6	1.499 (2)	C9—C10	1.393 (3)
C1—C2	1.533 (2)	C9—C16	1.511 (3)
C1—H1A	0.9900	C10—C11	1.386 (3)
C1—H1B	0.9900	C10—H10	0.9500
C2—C13	1.524 (2)	C11—C12	1.390 (3)
C2—C3	1.532 (2)	C11—H11	0.9500
C2—H2	1.0000	C12—H12	0.9500
C3—C14	1.517 (2)	C13—H13A	0.9800
C3—C4	1.552 (2)	C13—H13B	0.9800
C3—H3	1.0000	C13—H13C	0.9800
C4—C5	1.512 (2)	C15—H15A	0.9800
C4—C15	1.530 (2)	C15—H15B	0.9800
C4—H4	1.0000	C15—H15C	0.9800
C5—C6	1.349 (2)	C16—H16A	0.9800
C5—H5	0.9500	C16—H16B	0.9800
C6—C7	1.493 (2)	C16—H16C	0.9800
C7—C12	1.402 (2)

C14—O1—H1O	109.7 (18)	C9—C8—H8	119.2
C6—C1—C2	114.13 (13)	C7—C8—H8	119.2
C6—C1—H1A	108.7	C10—C9—C8	118.46 (16)
C2—C1—H1A	108.7	C10—C9—C16	120.77 (16)
C6—C1—H1B	108.7	C8—C9—C16	120.77 (17)
C2—C1—H1B	108.7	C11—C10—C9	120.85 (16)
H1A—C1—H1B	107.6	C11—C10—H10	119.6
C13—C2—C3	113.10 (14)	C9—C10—H10	119.6
C13—C2—C1	110.39 (14)	C10—C11—C12	120.39 (18)
C3—C2—C1	107.85 (13)	C10—C11—H11	119.8
C13—C2—H2	108.5	C12—C11—H11	119.8
C3—C2—H2	108.5	C11—C12—C7	120.30 (17)
C1—C2—H2	108.5	C11—C12—H12	119.9
C14—C3—C2	111.58 (13)	C7—C12—H12	119.9
C14—C3—C4	109.18 (13)	C2—C13—H13A	109.5
C2—C3—C4	111.55 (13)	C2—C13—H13B	109.5
C14—C3—H3	108.1	H13A—C13—H13B	109.5
C2—C3—H3	108.1	C2—C13—H13C	109.5
C4—C3—H3	108.1	H13A—C13—H13C	109.5
C5—C4—C15	110.23 (13)	H13B—C13—H13C	109.5
C5—C4—C3	110.51 (13)	O2—C14—O1	123.21 (15)
C15—C4—C3	109.93 (13)	O2—C14—C3	121.15 (15)
C5—C4—H4	108.7	O1—C14—C3	115.63 (15)
C15—C4—H4	108.7	C4—C15—H15A	109.5
C3—C4—H4	108.7	C4—C15—H15B	109.5
C6—C5—C4	124.97 (14)	H15A—C15—H15B	109.5
C6—C5—H5	117.5	C4—C15—H15C	109.5
C4—C5—H5	117.5	H15A—C15—H15C	109.5
C5—C6—C7	121.65 (14)	H15B—C15—H15C	109.5
C5—C6—C1	120.91 (14)	C9—C16—H16A	109.5
C7—C6—C1	117.33 (13)	C9—C16—H16B	109.5
C12—C7—C8	118.32 (15)	H16A—C16—H16B	109.5
C12—C7—C6	120.32 (15)	C9—C16—H16C	109.5
C8—C7—C6	121.34 (15)	H16A—C16—H16C	109.5
C9—C8—C7	121.65 (16)	H16B—C16—H16C	109.5

C6—C1—C2—C13	−172.47 (14)	C1—C6—C7—C12	−35.8 (2)
C6—C1—C2—C3	−48.44 (19)	C5—C6—C7—C8	−38.1 (2)
C13—C2—C3—C14	−52.09 (19)	C1—C6—C7—C8	145.50 (15)
C1—C2—C3—C14	−174.45 (14)	C12—C7—C8—C9	0.7 (2)
C13—C2—C3—C4	−174.51 (14)	C6—C7—C8—C9	179.46 (15)
C1—C2—C3—C4	63.12 (17)	C7—C8—C9—C10	−0.4 (2)
C14—C3—C4—C5	−168.20 (13)	C7—C8—C9—C16	−179.91 (16)
C2—C3—C4—C5	−44.41 (18)	C8—C9—C10—C11	−0.7 (3)
C14—C3—C4—C15	69.91 (17)	C16—C9—C10—C11	178.81 (18)
C2—C3—C4—C15	−166.30 (13)	C9—C10—C11—C12	1.5 (3)
C15—C4—C5—C6	133.15 (17)	C10—C11—C12—C7	−1.2 (3)
C3—C4—C5—C6	11.4 (2)	C8—C7—C12—C11	0.1 (2)
C4—C5—C6—C7	−173.87 (15)	C6—C7—C12—C11	−178.63 (15)
C4—C5—C6—C1	2.4 (3)	C2—C3—C14—O2	−59.64 (19)
C2—C1—C6—C5	17.0 (2)	C4—C3—C14—O2	64.14 (18)
C2—C1—C6—C7	−166.55 (14)	C2—C3—C14—O1	121.08 (15)
C5—C6—C7—C12	140.62 (17)	C4—C3—C14—O1	−115.15 (15)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···O2ⁱ	1.05 (3)	1.62 (3)	2.6628 (18)	174 (3)

Symmetry code: (i) −x+1, −y, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₆H₂₀O₂
M_r	244.32
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	150
a, b, c (Å)	11.2581 (10), 8.1055 (7), 29.857 (3)
V (Å³)	2724.5 (4)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.20 × 0.18 × 0.05

Data collection
Diffractometer	Bruker Kappa APEXII diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.985, 0.996
No. of measured, independent and observed [I > 2σ(I)] reflections	18515, 3120, 2265
R_int	0.043
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.136, 1.03
No. of reflections	3120
No. of parameters	170
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.50, −0.20

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···O2ⁱ	1.05 (3)	1.62 (3)	2.6628 (18)	174 (3)

Symmetry code: (i) −x+1, −y, −z+1.

Acknowledgements

SX and HS are grateful to the departmental fund and the Grant-in-aid for Faculty Research from Indiana University Kokomo, as well as a Senior Research Grant from Indiana Academy of Science.

References

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