supplementary materials


bt5185 scheme

Acta Cryst. (2010). E66, o567    [ doi:10.1107/S1600536810004423 ]

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

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

Abstract top

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

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.

Refinement top

All H atoms were placed in calculated positions, with C—H ranging from 0.95 Å to 0.99 Å and with Uiso(H) = 1.5Ueq(Cmethyl) or Uiso(H) = 1.2Ueq(C). The methyl groups were allowed to rotate but not to tip.

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
[Figure 1] Fig. 1. The structure of the title compound showing 30% probability displacement ellipsoids.
[Figure 2] 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
C14H18O2F(000) = 472
Mr = 218.28Dx = 1.176 Mg m3
Monoclinic, P21/nMelting point: 344.25 K
Hall symbol: -P 2ynMo Kα radiation, λ = 0.71073 Å
a = 8.7553 (6) ÅCell parameters from 2852 reflections
b = 6.0721 (4) Åθ = 2.5–27.0°
c = 23.2082 (17) ŵ = 0.08 mm1
β = 92.186 (1)°T = 173 K
V = 1232.92 (15) Å3Block, colourless
Z = 40.45 × 0.44 × 0.39 mm
Data collection top
Bruker SMART 1000 CCD
diffractometer
2662 independent reflections
Radiation source: fine-focus sealed tube1986 reflections with I > 2σ(I)
graphiteRint = 0.022
ω scansθmax = 27.0°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)
h = 114
Tmin = 0.966, Tmax = 0.971k = 77
5882 measured reflectionsl = 2729
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.045Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.131H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0698P)2 + 0.2701P]
where P = (Fo2 + 2Fc2)/3
2662 reflections(Δ/σ)max < 0.001
149 parametersΔρmax = 0.25 e Å3
0 restraintsΔρmin = 0.17 e Å3
Crystal data top
C14H18O2V = 1232.92 (15) Å3
Mr = 218.28Z = 4
Monoclinic, P21/nMo Kα radiation
a = 8.7553 (6) ŵ = 0.08 mm1
b = 6.0721 (4) ÅT = 173 K
c = 23.2082 (17) Å0.45 × 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)
Tmin = 0.966, Tmax = 0.971Rint = 0.022
5882 measured reflectionsθmax = 27.0°
Refinement top
R[F2 > 2σ(F2)] = 0.045H-atom parameters constrained
wR(F2) = 0.131Δρmax = 0.25 e Å3
S = 1.04Δρmin = 0.17 e Å3
2662 reflectionsAbsolute structure: ?
149 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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
xyzUiso*/Ueq
C10.00729 (15)0.4208 (2)0.12566 (5)0.0263 (3)
C20.10104 (15)0.2615 (2)0.13845 (6)0.0278 (3)
C30.09122 (16)0.1360 (2)0.18790 (6)0.0303 (3)
C40.02597 (17)0.1695 (3)0.22541 (6)0.0362 (4)
H40.03200.08250.25930.043*
C50.13474 (16)0.3316 (3)0.21305 (6)0.0370 (4)
H50.21540.35680.23850.044*
C60.12429 (15)0.4558 (2)0.16334 (6)0.0284 (3)
C70.22006 (17)0.6411 (3)0.13820 (6)0.0344 (4)
H7A0.19850.78130.15870.041*
H7B0.33050.60760.13970.041*
C80.16891 (15)0.6516 (2)0.07551 (6)0.0288 (3)
C90.26730 (18)0.5101 (3)0.03545 (7)0.0365 (4)
H9A0.22320.50650.00270.055*
H9B0.37070.57180.03220.055*
H9C0.27190.36010.05090.055*
C100.1533 (2)0.8823 (3)0.05219 (8)0.0426 (4)
H10A0.08170.96600.07720.064*
H10B0.25340.95490.05110.064*
H10C0.11480.87580.01310.064*
C110.21711 (19)0.0321 (3)0.18774 (7)0.0436 (4)
H11A0.17560.18210.18140.052*
H11B0.27830.02950.22450.052*
C120.31387 (17)0.0417 (3)0.13672 (7)0.0361 (4)
C130.3435 (2)0.1428 (3)0.09508 (9)0.0541 (5)
H13A0.24580.20210.08000.081*
H13B0.40150.25970.11510.081*
H13C0.40220.08650.06310.081*
C140.4577 (2)0.1601 (3)0.15651 (8)0.0552 (5)
H14A0.50940.21760.12290.083*
H14B0.52580.05730.17750.083*
H14C0.43170.28220.18190.083*
O10.01419 (11)0.55235 (18)0.07800 (4)0.0333 (3)
O20.21901 (12)0.2053 (2)0.10432 (4)0.0408 (3)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0245 (7)0.0291 (7)0.0254 (7)0.0008 (5)0.0020 (5)0.0003 (5)
C20.0230 (7)0.0322 (8)0.0282 (7)0.0018 (6)0.0028 (5)0.0035 (6)
C30.0259 (7)0.0317 (8)0.0329 (7)0.0001 (6)0.0033 (5)0.0010 (6)
C40.0309 (8)0.0484 (9)0.0295 (7)0.0024 (7)0.0010 (6)0.0120 (7)
C50.0260 (7)0.0565 (10)0.0288 (7)0.0044 (7)0.0065 (5)0.0053 (7)
C60.0241 (7)0.0341 (8)0.0272 (7)0.0020 (6)0.0015 (5)0.0024 (6)
C70.0321 (8)0.0383 (8)0.0330 (8)0.0093 (6)0.0025 (6)0.0032 (6)
C80.0242 (7)0.0285 (7)0.0339 (7)0.0040 (6)0.0018 (5)0.0005 (6)
C90.0379 (8)0.0350 (8)0.0364 (8)0.0012 (7)0.0006 (6)0.0028 (6)
C100.0421 (9)0.0302 (8)0.0547 (10)0.0037 (7)0.0068 (7)0.0061 (7)
C110.0390 (9)0.0416 (9)0.0501 (10)0.0108 (7)0.0015 (7)0.0082 (8)
C120.0266 (7)0.0388 (9)0.0425 (9)0.0087 (6)0.0041 (6)0.0028 (7)
C130.0450 (10)0.0521 (11)0.0649 (12)0.0124 (8)0.0022 (8)0.0167 (9)
C140.0455 (10)0.0595 (12)0.0595 (11)0.0107 (9)0.0124 (9)0.0016 (9)
O10.0268 (5)0.0397 (6)0.0339 (5)0.0067 (4)0.0074 (4)0.0099 (4)
O20.0341 (6)0.0526 (7)0.0365 (6)0.0184 (5)0.0103 (4)0.0057 (5)
Geometric parameters (Å, °) top
C1—O11.3639 (16)C9—H9A0.9800
C1—C21.3792 (19)C9—H9B0.9800
C1—C61.3882 (19)C9—H9C0.9800
C2—O21.3685 (16)C10—H10A0.9800
C2—C31.383 (2)C10—H10B0.9800
C3—C41.386 (2)C10—H10C0.9800
C3—C111.502 (2)C11—C121.548 (2)
C4—C51.392 (2)C11—H11A0.9900
C4—H40.9500C11—H11B0.9900
C5—C61.384 (2)C12—O21.4812 (18)
C5—H50.9500C12—C141.507 (2)
C6—C71.508 (2)C12—C131.509 (2)
C7—C81.540 (2)C13—H13A0.9800
C7—H7A0.9900C13—H13B0.9800
C7—H7B0.9900C13—H13C0.9800
C8—O11.4816 (16)C14—H14A0.9800
C8—C101.510 (2)C14—H14B0.9800
C8—C91.511 (2)C14—H14C0.9800
O1—C1—C2126.45 (12)H9A—C9—H9C109.5
O1—C1—C6114.22 (12)H9B—C9—H9C109.5
C2—C1—C6119.32 (13)C8—C10—H10A109.5
O2—C2—C1125.32 (13)C8—C10—H10B109.5
O2—C2—C3114.54 (12)H10A—C10—H10B109.5
C1—C2—C3120.07 (13)C8—C10—H10C109.5
C2—C3—C4120.76 (13)H10A—C10—H10C109.5
C2—C3—C11107.66 (13)H10B—C10—H10C109.5
C4—C3—C11131.47 (14)C3—C11—C12103.19 (12)
C3—C4—C5119.45 (13)C3—C11—H11A111.1
C3—C4—H4120.3C12—C11—H11A111.1
C5—C4—H4120.3C3—C11—H11B111.1
C6—C5—C4119.37 (13)C12—C11—H11B111.1
C6—C5—H5120.3H11A—C11—H11B109.1
C4—C5—H5120.3O2—C12—C14106.33 (13)
C5—C6—C1121.03 (13)O2—C12—C13106.23 (13)
C5—C6—C7132.51 (13)C14—C12—C13112.80 (15)
C1—C6—C7106.46 (12)O2—C12—C11105.66 (11)
C6—C7—C8102.64 (11)C14—C12—C11112.36 (14)
C6—C7—H7A111.2C13—C12—C11112.79 (15)
C8—C7—H7A111.2C12—C13—H13A109.5
C6—C7—H7B111.2C12—C13—H13B109.5
C8—C7—H7B111.2H13A—C13—H13B109.5
H7A—C7—H7B109.2C12—C13—H13C109.5
O1—C8—C10107.24 (12)H13A—C13—H13C109.5
O1—C8—C9106.96 (11)H13B—C13—H13C109.5
C10—C8—C9111.36 (12)C12—C14—H14A109.5
O1—C8—C7104.17 (10)C12—C14—H14B109.5
C10—C8—C7114.23 (13)H14A—C14—H14B109.5
C9—C8—C7112.23 (12)C12—C14—H14C109.5
C8—C9—H9A109.5H14A—C14—H14C109.5
C8—C9—H9B109.5H14B—C14—H14C109.5
H9A—C9—H9B109.5C1—O1—C8106.37 (10)
C8—C9—H9C109.5C2—O2—C12107.10 (11)
O1—C1—C2—O21.5 (2)C6—C7—C8—O123.68 (14)
C6—C1—C2—O2177.75 (13)C6—C7—C8—C10140.34 (13)
O1—C1—C2—C3178.26 (13)C6—C7—C8—C991.68 (14)
C6—C1—C2—C31.0 (2)C2—C3—C11—C128.91 (17)
O2—C2—C3—C4177.69 (13)C4—C3—C11—C12174.97 (15)
C1—C2—C3—C40.6 (2)C3—C11—C12—O213.11 (16)
O2—C2—C3—C111.07 (18)C3—C11—C12—C14102.42 (16)
C1—C2—C3—C11176.00 (13)C3—C11—C12—C13128.73 (14)
C2—C3—C4—C50.1 (2)C2—C1—O1—C8165.26 (13)
C11—C3—C4—C5175.75 (16)C6—C1—O1—C814.05 (15)
C3—C4—C5—C60.3 (2)C10—C8—O1—C1144.79 (12)
C4—C5—C6—C10.1 (2)C9—C8—O1—C195.65 (13)
C4—C5—C6—C7179.27 (15)C7—C8—O1—C123.36 (14)
O1—C1—C6—C5178.59 (13)C1—C2—O2—C12175.32 (13)
C2—C1—C6—C50.8 (2)C3—C2—O2—C127.79 (16)
O1—C1—C6—C71.89 (16)C14—C12—O2—C2106.65 (15)
C2—C1—C6—C7178.75 (12)C13—C12—O2—C2132.97 (14)
C5—C6—C7—C8164.44 (16)C11—C12—O2—C212.94 (16)
C1—C6—C7—C816.11 (15)
Acknowledgements top

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

references
References top

Bruker (2001). SMART. Bruker AXS Inc., Madison, Wisconsin, USA.

Bruker (2003). SAINT-Plus.Bruker AXS Inc., Madison, Wisconsin, USA.

Li, W.-S., Li, L. & Li, J.-S. (2009). Acta Cryst. E65, o2928.

Sheldrick, G. M. (2004). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Xu, L.-Z., Yu, G.-P. & Yang, S.-H. (2005). Acta Cryst. E61, o1924–o1926.