2,2,7,7-Tetra­methyl-2,3,6,7-tetra­hydro­benzofuro[7,6-b]furan

Luo, X.-F.; Yang, L.-T.; Wang, Y.; Zhang, J.-Y.; Hu, A.-X.

doi:10.1107/S1600536810004423

organic compounds

CRYSTALLOGRAPHIC
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ISSN: 2056-9890

Volume 66| Part 3| March 2010| Page o567

doi:10.1107/S1600536810004423

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2,2,7,7-Tetramethyl-2,3,6,7-tetrahydrobenzofuro[7,6-b]furan

Xian-Fu Luo,^a Lin-Tao Yang,^a Yu Wang,^b Jian-Yu Zhang ^b and Ai-Xi Hu ^a ^*

^aCollege of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China, and ^bHunan Research Institute of Chemical Industry, Changsha 410007, People's Republic of China
^*Correspondence e-mail: axhu0731@yahoo.com.cn

(Received 28 January 2010; accepted 4 February 2010; online 10 February 2010)

The title compound, C₁₄H₁₈O₂, was obtained as a by-product during the preparation of carbofuran phenol. The two dihydrofuran rings are in envelope conformations.

Related literature

For chemical background and related structures, see: Xu et al. (2005 ); Li et al. (2009 ).

Experimental

Crystal data

C₁₄H₁₈O₂
M_r = 218.28
Monoclinic, P 2₁ /n
a = 8.7553 (6) Å
b = 6.0721 (4) Å
c = 23.2082 (17) Å
β = 92.186 (1)°
V = 1232.92 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 173 K
0.45 × 0.44 × 0.39 mm

Data collection

Bruker SMART 1000 CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ) T_min = 0.966, T_max = 0.971
5882 measured reflections
2662 independent reflections
1986 reflections with I > 2σ(I)
R_int = 0.022

Refinement

R[F² > 2σ(F²)] = 0.045
wR(F²) = 0.131
S = 1.04
2662 reflections
149 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: SMART (Bruker, 2001 ); cell refinement: SAINT-Plus (Bruker, 2003 ); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, New_Global_Publ_Block. DOI: 10.1107/S1600536810004423/bt5185sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536810004423/bt5185Isup2.hkl

checkCIF report

Comment top

Carbofuran phenol (systematic name: 2,2-dimethy-2,3-dihydrobenzofuran-7-ol) is an important intermediate to prepare Carbofuran (Xu et al., 2005), Carbosulfan, Benfuracarb, Furathiocarb and other large tonnage carbamate pesticides. It also can be used as pharmaceutical intermediate, as a high value-added fine chemical product. The title compound, 2,2,7,7-tetramethyl-2,3,6,7-tetrahydrobenzofuro[7,6-b]furan, was obtained as a byproduct during the preparation of carbofuran phenol.

Related literature top

For chemical background and related structures, see: Xu et al. (2005); Li et al. (2009).

Experimental top

After distillation of carbofuran phenol, the fraction at 433.15 K(3.33 K Pa) was cooled to room temperature, then the precipitate was emerged. The solid was purified by recrystallization from saturated ethyl acetate solution, giving the title compound as a colourless crystalline solid. Single crystals suitable for X-ray diffraction were obtained by slow evaporation of an ethyl acetate solution at room temperature over a period of ten days. The identity of the title compound was confirmed by NMR and GC—MS spectroscopy.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus (Bruker, 2003); program(s) used to solve structure: SHELXTL (Sheldrick 2008); program(s) used to refine structure: SHELXTL (Sheldrick 2008); molecular graphics: SHELXTL (Sheldrick 2008); software used to prepare material for publication: SHELXTL (Sheldrick 2008).

Figures top

	Fig. 1. The structure of the title compound showing 30% probability displacement ellipsoids.
	Fig. 2. A packing diagram for the title compound. H atoms bonded to C atoms have been omitted for clarity.

2,2,7,7-Tetramethyl-2,3,6,7-tetrahydrobenzofuro[7,6-b]furan top

Crystal data top

C₁₄H₁₈O₂	F(000) = 472
M_r = 218.28	D_x = 1.176 Mg m⁻³
Monoclinic, P2₁/n	Melting point: 344.25 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 8.7553 (6) Å	Cell parameters from 2852 reflections
b = 6.0721 (4) Å	θ = 2.5–27.0°
c = 23.2082 (17) Å	µ = 0.08 mm⁻¹
β = 92.186 (1)°	T = 173 K
V = 1232.92 (15) Å³	Block, colourless
Z = 4	0.45 × 0.44 × 0.39 mm

Data collection top

Bruker SMART 1000 CCD diffractometer	2662 independent reflections
Radiation source: fine-focus sealed tube	1986 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.022
ω scans	θ_max = 27.0°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −11→4
T_min = 0.966, T_max = 0.971	k = −7→7
5882 measured reflections	l = −27→29

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.131	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0698P)² + 0.2701P] where P = (F_o² + 2F_c²)/3
2662 reflections	(Δ/σ)_max < 0.001
149 parameters	Δρ_max = 0.25 e Å⁻³
0 restraints	Δρ_min = −0.18 e Å⁻³

Crystal data top

C₁₄H₁₈O₂	V = 1232.92 (15) Å³
M_r = 218.28	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.7553 (6) Å	µ = 0.08 mm⁻¹
b = 6.0721 (4) Å	T = 173 K
c = 23.2082 (17) Å	0.45 × 0.44 × 0.39 mm
β = 92.186 (1)°

Data collection top

Bruker SMART 1000 CCD diffractometer	2662 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	1986 reflections with I > 2σ(I)
T_min = 0.966, T_max = 0.971	R_int = 0.022
5882 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.045	0 restraints
wR(F²) = 0.131	H-atom parameters constrained
S = 1.04	Δρ_max = 0.25 e Å⁻³
2662 reflections	Δρ_min = −0.18 e Å⁻³
149 parameters

Special details top

Experimental. ¹H NMR(300MHz, CDCl₃), delta: 1.49(s, 12H, CH₃); 2.99(s, 4H, CH₂); 6.63(s, 2H, C₆H₂). GC-MS(m/z): 218, 203, 185, 175, 161.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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
C1	−0.00729 (15)	0.4208 (2)	0.12566 (5)	0.0263 (3)
C2	0.10104 (15)	0.2615 (2)	0.13845 (6)	0.0278 (3)
C3	0.09122 (16)	0.1360 (2)	0.18790 (6)	0.0303 (3)
C4	−0.02597 (17)	0.1695 (3)	0.22541 (6)	0.0362 (4)
H4	−0.0320	0.0825	0.2593	0.043*
C5	−0.13474 (16)	0.3316 (3)	0.21305 (6)	0.0370 (4)
H5	−0.2154	0.3568	0.2385	0.044*
C6	−0.12429 (15)	0.4558 (2)	0.16334 (6)	0.0284 (3)
C7	−0.22006 (17)	0.6411 (3)	0.13820 (6)	0.0344 (4)
H7A	−0.1985	0.7813	0.1587	0.041*
H7B	−0.3305	0.6076	0.1397	0.041*
C8	−0.16891 (15)	0.6516 (2)	0.07551 (6)	0.0288 (3)
C9	−0.26730 (18)	0.5101 (3)	0.03545 (7)	0.0365 (4)
H9A	−0.2232	0.5065	−0.0027	0.055*
H9B	−0.3707	0.5718	0.0322	0.055*
H9C	−0.2719	0.3601	0.0509	0.055*
C10	−0.1533 (2)	0.8823 (3)	0.05219 (8)	0.0426 (4)
H10A	−0.0817	0.9660	0.0772	0.064*
H10B	−0.2534	0.9549	0.0511	0.064*
H10C	−0.1148	0.8758	0.0131	0.064*
C11	0.21711 (19)	−0.0321 (3)	0.18774 (7)	0.0436 (4)
H11A	0.1756	−0.1821	0.1814	0.052*
H11B	0.2783	−0.0295	0.2245	0.052*
C12	0.31387 (17)	0.0417 (3)	0.13672 (7)	0.0361 (4)
C13	0.3435 (2)	−0.1428 (3)	0.09508 (9)	0.0541 (5)
H13A	0.2458	−0.2021	0.0800	0.081*
H13B	0.4015	−0.2597	0.1151	0.081*
H13C	0.4022	−0.0865	0.0631	0.081*
C14	0.4577 (2)	0.1601 (3)	0.15651 (8)	0.0552 (5)
H14A	0.5094	0.2176	0.1229	0.083*
H14B	0.5258	0.0573	0.1775	0.083*
H14C	0.4317	0.2822	0.1819	0.083*
O1	−0.01419 (11)	0.55235 (18)	0.07800 (4)	0.0333 (3)
O2	0.21901 (12)	0.2053 (2)	0.10432 (4)	0.0408 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0245 (7)	0.0291 (7)	0.0254 (7)	−0.0008 (5)	0.0020 (5)	−0.0003 (5)
C2	0.0230 (7)	0.0322 (8)	0.0282 (7)	0.0018 (6)	0.0028 (5)	−0.0035 (6)
C3	0.0259 (7)	0.0317 (8)	0.0329 (7)	−0.0001 (6)	−0.0033 (5)	0.0010 (6)
C4	0.0309 (8)	0.0484 (9)	0.0295 (7)	−0.0024 (7)	0.0010 (6)	0.0120 (7)
C5	0.0260 (7)	0.0565 (10)	0.0288 (7)	0.0044 (7)	0.0065 (5)	0.0053 (7)
C6	0.0241 (7)	0.0341 (8)	0.0272 (7)	0.0020 (6)	0.0015 (5)	−0.0024 (6)
C7	0.0321 (8)	0.0383 (8)	0.0330 (8)	0.0093 (6)	0.0025 (6)	−0.0032 (6)
C8	0.0242 (7)	0.0285 (7)	0.0339 (7)	0.0040 (6)	0.0018 (5)	0.0005 (6)
C9	0.0379 (8)	0.0350 (8)	0.0364 (8)	−0.0012 (7)	−0.0006 (6)	−0.0028 (6)
C10	0.0421 (9)	0.0302 (8)	0.0547 (10)	−0.0037 (7)	−0.0068 (7)	0.0061 (7)
C11	0.0390 (9)	0.0416 (9)	0.0501 (10)	0.0108 (7)	0.0015 (7)	0.0082 (8)
C12	0.0266 (7)	0.0388 (9)	0.0425 (9)	0.0087 (6)	−0.0041 (6)	−0.0028 (7)
C13	0.0450 (10)	0.0521 (11)	0.0649 (12)	0.0124 (8)	−0.0022 (8)	−0.0167 (9)
C14	0.0455 (10)	0.0595 (12)	0.0595 (11)	−0.0107 (9)	−0.0124 (9)	0.0016 (9)
O1	0.0268 (5)	0.0397 (6)	0.0339 (5)	0.0067 (4)	0.0074 (4)	0.0099 (4)
O2	0.0341 (6)	0.0526 (7)	0.0365 (6)	0.0184 (5)	0.0103 (4)	0.0057 (5)

Geometric parameters (Å, º) top

C1—O1	1.3639 (16)	C9—H9A	0.9800
C1—C2	1.3792 (19)	C9—H9B	0.9800
C1—C6	1.3882 (19)	C9—H9C	0.9800
C2—O2	1.3685 (16)	C10—H10A	0.9800
C2—C3	1.383 (2)	C10—H10B	0.9800
C3—C4	1.386 (2)	C10—H10C	0.9800
C3—C11	1.502 (2)	C11—C12	1.548 (2)
C4—C5	1.392 (2)	C11—H11A	0.9900
C4—H4	0.9500	C11—H11B	0.9900
C5—C6	1.384 (2)	C12—O2	1.4812 (18)
C5—H5	0.9500	C12—C14	1.507 (2)
C6—C7	1.508 (2)	C12—C13	1.509 (2)
C7—C8	1.540 (2)	C13—H13A	0.9800
C7—H7A	0.9900	C13—H13B	0.9800
C7—H7B	0.9900	C13—H13C	0.9800
C8—O1	1.4816 (16)	C14—H14A	0.9800
C8—C10	1.510 (2)	C14—H14B	0.9800
C8—C9	1.511 (2)	C14—H14C	0.9800

O1—C1—C2	126.45 (12)	H9A—C9—H9C	109.5
O1—C1—C6	114.22 (12)	H9B—C9—H9C	109.5
C2—C1—C6	119.32 (13)	C8—C10—H10A	109.5
O2—C2—C1	125.32 (13)	C8—C10—H10B	109.5
O2—C2—C3	114.54 (12)	H10A—C10—H10B	109.5
C1—C2—C3	120.07 (13)	C8—C10—H10C	109.5
C2—C3—C4	120.76 (13)	H10A—C10—H10C	109.5
C2—C3—C11	107.66 (13)	H10B—C10—H10C	109.5
C4—C3—C11	131.47 (14)	C3—C11—C12	103.19 (12)
C3—C4—C5	119.45 (13)	C3—C11—H11A	111.1
C3—C4—H4	120.3	C12—C11—H11A	111.1
C5—C4—H4	120.3	C3—C11—H11B	111.1
C6—C5—C4	119.37 (13)	C12—C11—H11B	111.1
C6—C5—H5	120.3	H11A—C11—H11B	109.1
C4—C5—H5	120.3	O2—C12—C14	106.33 (13)
C5—C6—C1	121.03 (13)	O2—C12—C13	106.23 (13)
C5—C6—C7	132.51 (13)	C14—C12—C13	112.80 (15)
C1—C6—C7	106.46 (12)	O2—C12—C11	105.66 (11)
C6—C7—C8	102.64 (11)	C14—C12—C11	112.36 (14)
C6—C7—H7A	111.2	C13—C12—C11	112.79 (15)
C8—C7—H7A	111.2	C12—C13—H13A	109.5
C6—C7—H7B	111.2	C12—C13—H13B	109.5
C8—C7—H7B	111.2	H13A—C13—H13B	109.5
H7A—C7—H7B	109.2	C12—C13—H13C	109.5
O1—C8—C10	107.24 (12)	H13A—C13—H13C	109.5
O1—C8—C9	106.96 (11)	H13B—C13—H13C	109.5
C10—C8—C9	111.36 (12)	C12—C14—H14A	109.5
O1—C8—C7	104.17 (10)	C12—C14—H14B	109.5
C10—C8—C7	114.23 (13)	H14A—C14—H14B	109.5
C9—C8—C7	112.23 (12)	C12—C14—H14C	109.5
C8—C9—H9A	109.5	H14A—C14—H14C	109.5
C8—C9—H9B	109.5	H14B—C14—H14C	109.5
H9A—C9—H9B	109.5	C1—O1—C8	106.37 (10)
C8—C9—H9C	109.5	C2—O2—C12	107.10 (11)

O1—C1—C2—O2	−1.5 (2)	C6—C7—C8—O1	−23.68 (14)
C6—C1—C2—O2	177.75 (13)	C6—C7—C8—C10	−140.34 (13)
O1—C1—C2—C3	−178.26 (13)	C6—C7—C8—C9	91.68 (14)
C6—C1—C2—C3	1.0 (2)	C2—C3—C11—C12	8.91 (17)
O2—C2—C3—C4	−177.69 (13)	C4—C3—C11—C12	−174.97 (15)
C1—C2—C3—C4	−0.6 (2)	C3—C11—C12—O2	−13.11 (16)
O2—C2—C3—C11	−1.07 (18)	C3—C11—C12—C14	102.42 (16)
C1—C2—C3—C11	176.00 (13)	C3—C11—C12—C13	−128.73 (14)
C2—C3—C4—C5	−0.1 (2)	C2—C1—O1—C8	165.26 (13)
C11—C3—C4—C5	−175.75 (16)	C6—C1—O1—C8	−14.05 (15)
C3—C4—C5—C6	0.3 (2)	C10—C8—O1—C1	144.79 (12)
C4—C5—C6—C1	0.1 (2)	C9—C8—O1—C1	−95.65 (13)
C4—C5—C6—C7	−179.27 (15)	C7—C8—O1—C1	23.36 (14)
O1—C1—C6—C5	178.59 (13)	C1—C2—O2—C12	175.32 (13)
C2—C1—C6—C5	−0.8 (2)	C3—C2—O2—C12	−7.79 (16)
O1—C1—C6—C7	−1.89 (16)	C14—C12—O2—C2	−106.65 (15)
C2—C1—C6—C7	178.75 (12)	C13—C12—O2—C2	132.97 (14)
C5—C6—C7—C8	−164.44 (16)	C11—C12—O2—C2	12.94 (16)
C1—C6—C7—C8	16.11 (15)

Experimental details

Crystal data
Chemical formula	C₁₄H₁₈O₂
M_r	218.28
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	173
a, b, c (Å)	8.7553 (6), 6.0721 (4), 23.2082 (17)
β (°)	92.186 (1)
V (Å³)	1232.92 (15)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.45 × 0.44 × 0.39

Data collection
Diffractometer	Bruker SMART 1000 CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2004)
T_min, T_max	0.966, 0.971
No. of measured, independent and observed [I > 2σ(I)] reflections	5882, 2662, 1986
R_int	0.022
(sin θ/λ)_max (Å⁻¹)	0.640

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.045, 0.131, 1.04
No. of reflections	2662
No. of parameters	149
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.25, −0.18

Computer programs: SMART (Bruker, 2001), SAINT-Plus (Bruker, 2003), SHELXTL (Sheldrick 2008).

Acknowledgements

This work was supported by the Central University Basic Scientific Research Fund of Hunan University.

References

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Bruker (2003). SAINT-Plus.Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
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Sheldrick, G. M. (2004). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Xu, L.-Z., Yu, G.-P. & Yang, S.-H. (2005). Acta Cryst. E61, o1924–o1926. Web of Science CSD CrossRef IUCr Journals Google Scholar