3,3-Bis(2-furyl­methyl)-2-methyl-4-oxo­cyclo­hex-1-ene-1-carboxyl­ic acid

In the title mol­ecule, C₁₈H₁₈O₅, the cyclo­hexene ring adopts an envelope conformation. The dihedral angle between the two furan rings is 65.9 (1)°. In the crystal structure, the carboxyl groups of inversion-related moleules are involved in the formation of dimers through O—H...O hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.048
• wR factor = 0.139
• Data-to-parameter ratio = 18.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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Computing details

Data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1997); software used to prepare material for publication: SHELXTL.

3,3-Bis(2-furylmethyl)-2-methyl-4-oxocyclohex-1-ene-1-carboxylic acid

Crystal data

C18H18O5	F(000) = 664
Mr = 314.32	Dx = 1.300 Mg m^−3
Monoclinic, P21/n	Melting point = 415–416 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 7.125 (1) Å	Cell parameters from 5554 reflections
b = 8.798 (1) Å	θ = 2.0–28.0°
c = 25.625 (2) Å	µ = 0.10 mm^−1
β = 91.214 (1)°	T = 298 K
V = 1606.0 (3) Å^3	Block, colourless
Z = 4	0.55 × 0.55 × 0.55 mm

Data collection

Bruker CCD area-detector diffractometer	3824 independent reflections
Radiation source: fine-focus sealed tube	3057 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.020
ω scans	θmax = 28.3°, θmin = 1.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.866, Tmax = 0.950	k = −7→11
9924 measured reflections	l = −34→34

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.048	H-atom parameters constrained
wR(F^2) = 0.139	w = 1/[σ^2(Fo^2) + (0.0606P)^2 + 0.5648P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
3824 reflections	Δρmax = 0.44 e Å^−3
211 parameters	Δρmin = −0.29 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.036 (3)

Special details

Experimental. Data was collected using a Siemens SMART CCD based diffractometer operating at room temperature. Data was measured using omega scans of 0.3 degrees per frame for 60 s. A total of 1271 frames were collected. The first 50 frames were recollected at the end of each set of frames. As usual in organic compounds high theta reflections are too weak to be measured.

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.50501 (18)	−0.06063 (13)	0.07156 (5)	0.0511 (3)
O2	0.08922 (19)	0.41687 (14)	0.19161 (5)	0.0575 (3)
O3	0.17284 (19)	0.42311 (17)	0.03333 (6)	0.0732 (5)
O4	−0.1097 (2)	0.3277 (2)	0.02231 (8)	0.0913 (6)
H4	−0.1241	0.4062	0.0054	0.137*
O5	0.0530 (2)	−0.12106 (16)	0.19199 (5)	0.0641 (4)
C1	0.2466 (2)	0.07479 (16)	0.15724 (5)	0.0368 (3)
C2	0.2409 (2)	0.18759 (15)	0.11161 (5)	0.0354 (3)
C3	0.0899 (2)	0.19500 (16)	0.07925 (5)	0.0371 (3)
C4	−0.0659 (2)	0.0783 (2)	0.07930 (7)	0.0497 (4)
H4A	−0.1131	0.0634	0.0439	0.060*
H4B	−0.1684	0.1158	0.1000	0.060*
C5	0.0022 (2)	−0.07322 (18)	0.10144 (7)	0.0489 (4)
H5A	−0.1031	−0.1423	0.1046	0.059*
H5B	0.0916	−0.1186	0.0781	0.059*
C6	0.0929 (2)	−0.04797 (17)	0.15373 (6)	0.0418 (3)
C7	0.4354 (2)	−0.01357 (18)	0.16283 (6)	0.0438 (4)
H7A	0.5370	0.0597	0.1652	0.053*
H7B	0.4352	−0.0698	0.1954	0.053*
C8	0.4753 (2)	−0.12121 (18)	0.11987 (6)	0.0427 (4)
C9	0.4922 (3)	−0.2730 (2)	0.11726 (9)	0.0643 (5)
H9	0.4793	−0.3412	0.1447	0.077*
C10	0.5337 (3)	−0.3100 (2)	0.06482 (9)	0.0697 (6)
H10	0.5523	−0.4067	0.0513	0.084*
C11	0.5406 (3)	−0.1803 (2)	0.03906 (8)	0.0610 (5)
H11	0.5662	−0.1714	0.0038	0.073*
C12	0.2219 (3)	0.16615 (19)	0.20880 (6)	0.0469 (4)
H12A	0.2080	0.0949	0.2373	0.056*
H12B	0.3351	0.2247	0.2158	0.056*
C13	0.0582 (2)	0.27135 (18)	0.20794 (6)	0.0445 (4)
C14	−0.1238 (3)	0.2560 (2)	0.21980 (8)	0.0596 (5)
H14	−0.1814	0.1688	0.2322	0.072*
C15	−0.2121 (3)	0.3995 (3)	0.20963 (9)	0.0657 (5)
H15	−0.3380	0.4233	0.2138	0.079*
C16	−0.0798 (3)	0.4913 (2)	0.19320 (8)	0.0650 (5)
H16	−0.0984	0.5925	0.1840	0.078*
C17	0.4037 (2)	0.29670 (19)	0.11044 (7)	0.0492 (4)
H17A	0.4706	0.2830	0.0787	0.074*
H17B	0.4865	0.2775	0.1397	0.074*
H17C	0.3577	0.3991	0.1122	0.074*
C18	0.0581 (2)	0.32553 (18)	0.04317 (6)	0.0420 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0608 (7)	0.0451 (6)	0.0475 (6)	−0.0009 (5)	0.0034 (5)	0.0046 (5)
O2	0.0720 (8)	0.0389 (6)	0.0619 (8)	0.0000 (6)	0.0062 (6)	0.0011 (5)
O3	0.0548 (7)	0.0685 (9)	0.0957 (11)	−0.0101 (6)	−0.0172 (7)	0.0485 (8)
O4	0.0679 (9)	0.0822 (11)	0.1218 (14)	−0.0208 (8)	−0.0480 (9)	0.0616 (10)
O5	0.0846 (10)	0.0535 (7)	0.0545 (7)	−0.0142 (7)	0.0064 (6)	0.0199 (6)
C1	0.0453 (8)	0.0324 (7)	0.0324 (7)	−0.0001 (6)	−0.0054 (6)	0.0037 (5)
C2	0.0421 (7)	0.0299 (7)	0.0341 (7)	−0.0026 (5)	−0.0033 (5)	0.0031 (5)
C3	0.0407 (7)	0.0347 (7)	0.0358 (7)	−0.0014 (6)	−0.0030 (5)	0.0061 (6)
C4	0.0458 (8)	0.0486 (9)	0.0542 (9)	−0.0110 (7)	−0.0129 (7)	0.0132 (7)
C5	0.0533 (9)	0.0389 (8)	0.0541 (9)	−0.0137 (7)	−0.0090 (7)	0.0049 (7)
C6	0.0476 (8)	0.0326 (7)	0.0452 (8)	−0.0001 (6)	0.0015 (6)	0.0075 (6)
C7	0.0481 (8)	0.0419 (8)	0.0410 (8)	0.0035 (6)	−0.0096 (6)	0.0064 (6)
C8	0.0415 (8)	0.0395 (8)	0.0470 (8)	0.0008 (6)	−0.0031 (6)	0.0071 (6)
C9	0.0826 (14)	0.0392 (9)	0.0715 (13)	0.0005 (9)	0.0117 (10)	0.0072 (8)
C10	0.0830 (14)	0.0453 (10)	0.0812 (14)	−0.0069 (10)	0.0143 (11)	−0.0135 (10)
C11	0.0655 (11)	0.0621 (12)	0.0558 (10)	−0.0038 (9)	0.0079 (9)	−0.0113 (9)
C12	0.0636 (10)	0.0428 (8)	0.0339 (7)	0.0040 (7)	−0.0082 (7)	0.0003 (6)
C13	0.0629 (10)	0.0366 (8)	0.0338 (7)	−0.0019 (7)	−0.0032 (6)	−0.0032 (6)
C14	0.0701 (12)	0.0498 (10)	0.0591 (11)	−0.0141 (9)	0.0073 (9)	−0.0087 (8)
C15	0.0592 (11)	0.0653 (12)	0.0721 (13)	0.0050 (10)	−0.0068 (9)	−0.0218 (10)
C16	0.0830 (14)	0.0462 (10)	0.0652 (12)	0.0150 (10)	−0.0070 (10)	−0.0055 (9)
C17	0.0496 (9)	0.0432 (9)	0.0542 (9)	−0.0120 (7)	−0.0128 (7)	0.0117 (7)
C18	0.0432 (8)	0.0429 (8)	0.0396 (8)	0.0004 (6)	−0.0044 (6)	0.0102 (6)

Geometric parameters (Å, º)

O1—C8	1.3684 (19)	C7—C8	1.484 (2)
O1—C11	1.369 (2)	C7—H7A	0.97
O2—C13	1.366 (2)	C7—H7B	0.97
O2—C16	1.372 (2)	C8—C9	1.343 (2)
O3—C18	1.216 (2)	C9—C10	1.420 (3)
O4—C18	1.299 (2)	C9—H9	0.93
O4—H4	0.82	C10—C11	1.320 (3)
O5—C6	1.212 (2)	C10—H10	0.93
C1—C2	1.533 (2)	C11—H11	0.93
C1—C6	1.539 (2)	C12—C13	1.488 (2)
C1—C7	1.558 (2)	C12—H12A	0.97
C1—C12	1.560 (2)	C12—H12B	0.97
C2—C3	1.346 (2)	C13—C14	1.345 (3)
C2—C17	1.507 (2)	C14—C15	1.432 (3)
C3—C18	1.489 (2)	C14—H14	0.93
C3—C4	1.512 (2)	C15—C16	1.316 (3)
C4—C5	1.524 (2)	C15—H15	0.93
C4—H4A	0.97	C16—H16	0.93
C4—H4B	0.97	C17—H17A	0.96
C5—C6	1.492 (2)	C17—H17B	0.96
C5—H5A	0.97	C17—H17C	0.96
C5—H5B	0.97
C8—O1—C11	106.56 (14)	O1—C8—C7	117.27 (13)
C13—O2—C16	106.88 (15)	C8—C9—C10	107.21 (18)
C18—O4—H4	109.5	C8—C9—H9	126.4
C2—C1—C6	113.70 (11)	C10—C9—H9	126.4
C2—C1—C7	113.71 (12)	C11—C10—C9	106.63 (18)
C6—C1—C7	105.50 (12)	C11—C10—H10	126.7
C2—C1—C12	108.11 (12)	C9—C10—H10	126.7
C6—C1—C12	108.55 (12)	C10—C11—O1	110.55 (18)
C7—C1—C12	106.98 (12)	C10—C11—H11	124.7
C3—C2—C17	124.23 (13)	O1—C11—H11	124.7
C3—C2—C1	120.62 (12)	C13—C12—C1	114.22 (13)
C17—C2—C1	114.79 (12)	C13—C12—H12A	108.7
C2—C3—C18	121.96 (13)	C1—C12—H12A	108.7
C2—C3—C4	122.94 (13)	C13—C12—H12B	108.7
C18—C3—C4	114.96 (12)	C1—C12—H12B	108.7
C3—C4—C5	111.47 (13)	H12A—C12—H12B	107.6
C3—C4—H4A	109.3	C14—C13—O2	109.02 (16)
C5—C4—H4A	109.3	C14—C13—C12	133.87 (16)
C3—C4—H4B	109.3	O2—C13—C12	117.10 (15)
C5—C4—H4B	109.3	C13—C14—C15	106.99 (18)
H4A—C4—H4B	108.0	C13—C14—H14	126.5
C6—C5—C4	109.42 (14)	C15—C14—H14	126.5
C6—C5—H5A	109.8	C16—C15—C14	106.52 (18)
C4—C5—H5A	109.8	C16—C15—H15	126.7
C6—C5—H5B	109.8	C14—C15—H15	126.7
C4—C5—H5B	109.8	C15—C16—O2	110.58 (18)
H5A—C5—H5B	108.2	C15—C16—H16	124.7
O5—C6—C5	122.91 (15)	O2—C16—H16	124.7
O5—C6—C1	120.26 (15)	C2—C17—H17A	109.5
C5—C6—C1	116.81 (12)	C2—C17—H17B	109.5
C8—C7—C1	115.38 (12)	H17A—C17—H17B	109.5
C8—C7—H7A	108.4	C2—C17—H17C	109.5
C1—C7—H7A	108.4	H17A—C17—H17C	109.5
C8—C7—H7B	108.4	H17B—C17—H17C	109.5
C1—C7—H7B	108.4	O3—C18—O4	121.43 (14)
H7A—C7—H7B	107.5	O3—C18—C3	125.40 (14)
C9—C8—O1	109.05 (16)	O4—C18—C3	113.17 (14)
C9—C8—C7	133.67 (16)
C6—C1—C2—C3	13.9 (2)	C11—O1—C8—C7	179.30 (14)
C7—C1—C2—C3	134.62 (15)	C1—C7—C8—C9	−114.8 (2)
C12—C1—C2—C3	−106.75 (16)	C1—C7—C8—O1	66.21 (18)
C6—C1—C2—C17	−172.67 (13)	O1—C8—C9—C10	−0.3 (2)
C7—C1—C2—C17	−51.90 (17)	C7—C8—C9—C10	−179.33 (18)
C12—C1—C2—C17	66.73 (17)	C8—C9—C10—C11	0.4 (3)
C17—C2—C3—C18	−8.1 (2)	C9—C10—C11—O1	−0.4 (3)
C1—C2—C3—C18	164.75 (14)	C8—O1—C11—C10	0.2 (2)
C17—C2—C3—C4	176.29 (16)	C2—C1—C12—C13	50.65 (18)
C1—C2—C3—C4	−10.9 (2)	C6—C1—C12—C13	−73.11 (16)
C2—C3—C4—C5	−23.7 (2)	C7—C1—C12—C13	173.49 (14)
C18—C3—C4—C5	160.35 (15)	C16—O2—C13—C14	−0.58 (19)
C3—C4—C5—C6	53.2 (2)	C16—O2—C13—C12	179.03 (14)
C4—C5—C6—O5	129.77 (17)	C1—C12—C13—C14	88.4 (2)
C4—C5—C6—C1	−51.72 (19)	C1—C12—C13—O2	−91.04 (17)
C2—C1—C6—O5	−162.71 (15)	O2—C13—C14—C15	0.8 (2)
C7—C1—C6—O5	72.02 (18)	C12—C13—C14—C15	−178.71 (17)
C12—C1—C6—O5	−42.35 (19)	C13—C14—C15—C16	−0.7 (2)
C2—C1—C6—C5	18.74 (19)	C14—C15—C16—O2	0.4 (2)
C7—C1—C6—C5	−106.53 (15)	C13—O2—C16—C15	0.1 (2)
C12—C1—C6—C5	139.10 (14)	C2—C3—C18—O3	11.8 (3)
C2—C1—C7—C8	−67.05 (17)	C4—C3—C18—O3	−172.2 (2)
C6—C1—C7—C8	58.21 (16)	C2—C3—C18—O4	−167.8 (2)
C12—C1—C7—C8	173.67 (13)	C4—C3—C18—O4	8.2 (2)
C11—O1—C8—C9	0.1 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O3^i	0.82	1.83	2.649 (2)	176
C12—H12A···O5	0.97	2.47	2.828 (2)	101
C17—H17C···O3	0.96	2.40	2.777 (2)	103

Symmetry code: (i) −x, −y+1, −z.