organic compounds
4-[(tert-Butyldimethylsilyl)oxy]-6-methoxy-7-methyl-5-(oxiran-2-ylmethyl)-2-benzofuran-3(1H)-one
aChemical Faculty, Gdansk University of Technology, Narutowicza 11/12, Gdansk PL-80233, Poland
*Correspondence e-mail: gch@chem.pg.gda.pl
The title compound, C19H28O5Si, was obtained in the reaction of 1,3-dihydro-4-[(tert-butyldimethylsilyl)oxy]-6-methoxy-7-methyl-3-oxo-5-(prop-2-enyl)isobenzofuran with meta-chloroperbenzoic acid. This reaction is one of the stages of the total synthesis of mycophenolic acid, which we attempted to modify. The title compound forms crystals with only weak intermolecular interactions. The strongest stacking interaction is found between the benzene and furan rings of inversion-related molecules with a distance of 3.8773 (13) Å between the ring centroids.
Related literature
For structures of related oxiranes, see: Langer & Becker (1993); Berthalon et al. (1999). For the preparation of the title compound, see: Patterson (1995); Plé et al. (1997). For the properties of see: Padwa & Murphree (2006). For a description of the Cambridge Structural Database, see Allen (2002).
Experimental
Crystal data
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Data collection: CrysAlis PRO (Agilent, 2010); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2010), PLATON (Spek, 2009), WinGX (Farrugia, 1999) and Mercury (Macrae et al., 2006).
Supporting information
https://doi.org/10.1107/S1600536811049026/fy2029sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536811049026/fy2029Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S1600536811049026/fy2029Isup3.cml
The starting material 1,3-dihydro-4-[(tert-butyldimethylsilyl)oxy]-6-methoxy-7-methyl-3-oxo-5-(prop-2-enyl)isobenzofuran was obtained according to the chemical literature (Patterson, 1995).
Preparation of 1,3-dihydro-4-[(tert-butyldimethylsilyl)oxy]-6-methoxy-7-methyl-3-oxo-5-(2,3-epoxypropanyl)isobenzofuran, was carried out based on the procedure reported in the chemical literature (Plé et al., 1997). In the cited work geranyl acetate was oxidized to 6,7-epoxygeranyl acetate with meta-chloroperoxybenzoic acid (m-CPBA). We applied lower temperature for addition of m-CPBA (–70 °C, instead of – 30 °C), and then the reaction was carried out at room temperature (instead of 0 °C).
The solution of 1,3-dihydro-4-[(tert-butyldimethylsilyl)oxy]-6-methoxy-7-methyl-3-oxo-5-(prop-2-enyl)isobenzofuran (6.5 mmol), freshly melted sodium acetate (6.5 mmol) in anhydrous methyl chloride (20 ml) was cooled to –70 °C. Subsequently, m-CPBA (13 mmol) (meta-chloroperbenzoic acid) was added portionwise and the reaction mixture was stirred at room temperature for 5 h. Then it was washed with diluted NaHCO3, and the aqueous layer was extracted with methylene chloride. Next, the combined organic layers were washed with cooled 1M NaOH, dried over Na2SO4 and filtered and evaporated under vacuum. The crude product was purified with
(petroleum ether – ethyl acetate 10:1) to give 3-dihydro-4-[(tert-butyldimethylsilyl)oxy]-6-methoxy-7-methyl-3-oxo-5-(2,3-epoxypropanyl)isobenzofuran in 80% yield.Single crystals were obtained by vapour diffusion of petroleum ether into a solution of about 30 mg product in 1 mL dichloromethane over 3-4 days (m.p. 96–98 °C).
All hydrogen atoms were refined in isotropic approximation with U values fixed to be 1.5 times Ueq of C atoms for CH3 or 1.2 times Ueq for CH2 and CH groups. C12 oxiran atom was found disordered over two positions (with 0.839 (6)/0.161 (6) probablilities). The same splitting ratio was applied to the disorder of the neighbouring O4—C13 methoxy group and the second neighbour C8 methyl group to avoid short contacts within the molecule.
Presented research is an attempt to modify the known multi-stage total synthesis of mycophenolic acid (Patterson, 1995) by making use of
as intermediates. The synthesis of the desired epoxide was successful and its X-ray structure has been determined.In the title compound, bond length C12—C13 is ca 0.01 Å longer than C12—O5 or C13—O5, which is a trend noted for other oxirans. The valence angle at O5 is close to the average of 60.5 (9)° calculated for 17 structures containing benzyloxirane fragment, according to our CSD search (Allen et al., 2002). The most closely related compounds, which contain the 1-phenyl-2,3-epoxypropane fragment are rac-3-(9-anthryl)-1,2-epoxypropane (Langer et al., 1993) and a modified calix[4]arene (Berthalon et al., 1999).
The
is composed of discrete molecules with no strong specific intermolecular interactions. The strongest stacking interaction is found between the benzene and furan rings of molecules related by the inversion at (1/2, 1/2, 1) with a distance of 3.8773 (13) Å between the ring centroids.The ORTEP view of the title epoxide is given in Fig. 1. Although the oxirane ring is not connected with the aromatic ring directly, the shortest intramolecular contact between the ring and adjacent methoxy substituent is rather short 2.560 (3) Å for O5···H11A.
are known to be reactive compounds (Padwa et al., 2006), but the investigated oxirane is relatively stable and can be purified on silica gel and stored for several months. We suppose the reactivity of the epoxide ring is decreased by the from the proximate methoxyl and t-BuMe2Si substituents.For structures of related oxiranes, see: Langer & Becker (1993); Berthalon et al. (1999). For the preparation of the title compound, see: Patterson (1995); Plé et al. (1997). For the properties of
see: Padwa & Murphree (2006). For a description of the Cambridge Structural Database, see Allen (2002).Data collection: CrysAlis PRO (Agilent, 2010); cell
CrysAlis PRO (Agilent, 2010); data reduction: CrysAlis PRO (Agilent, 2010); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2010), PLATON (Spek, 2009), WinGX (Farrugia, 1999) and Mercury (Macrae et al., 2006).Fig. 1. Molecular structure of C19H28O5Si, showing the atomic labeling scheme. Displacement ellipsoids are drawn at the 50% probability level. |
C19H28O5Si | F(000) = 784 |
Mr = 364.5 | Dx = 1.265 Mg m−3 |
Monoclinic, P21/c | Melting point: 369(2) K |
Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71073 Å |
a = 7.5682 (3) Å | Cell parameters from 4883 reflections |
b = 12.2488 (4) Å | θ = 2.6–28.8° |
c = 20.6905 (8) Å | µ = 0.15 mm−1 |
β = 93.990 (4)° | T = 120 K |
V = 1913.39 (12) Å3 | Block, colourless |
Z = 4 | 0.55 × 0.44 × 0.35 mm |
Agilent Xcalibur diffractometer | 3430 independent reflections |
Graphite monochromator | 2858 reflections with I > 2σ(I) |
Detector resolution: 8.1883 pixels mm-1 | Rint = 0.017 |
ω scans | θmax = 25.2°, θmin = 2.6° |
Absorption correction: analytical (Clark & Reid, 1995) | h = −9→7 |
Tmin = 0.938, Tmax = 0.954 | k = −13→14 |
6727 measured reflections | l = −23→24 |
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) = 0.123 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.075P)2 + 0.4245P] where P = (Fo2 + 2Fc2)/3 |
3430 reflections | (Δ/σ)max = 0.013 |
243 parameters | Δρmax = 0.42 e Å−3 |
2 restraints | Δρmin = −0.18 e Å−3 |
C19H28O5Si | V = 1913.39 (12) Å3 |
Mr = 364.5 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.5682 (3) Å | µ = 0.15 mm−1 |
b = 12.2488 (4) Å | T = 120 K |
c = 20.6905 (8) Å | 0.55 × 0.44 × 0.35 mm |
β = 93.990 (4)° |
Agilent Xcalibur diffractometer | 3430 independent reflections |
Absorption correction: analytical (Clark & Reid, 1995) | 2858 reflections with I > 2σ(I) |
Tmin = 0.938, Tmax = 0.954 | Rint = 0.017 |
6727 measured reflections |
R[F2 > 2σ(F2)] = 0.045 | 2 restraints |
wR(F2) = 0.123 | H-atom parameters constrained |
S = 1.09 | Δρmax = 0.42 e Å−3 |
3430 reflections | Δρmin = −0.18 e Å−3 |
243 parameters |
Experimental. 1H NMR (CDCl3, δ): 0.25 (s, 3H), 0.26 (s, 3H), 1.04 (s, 9H), 2.18 (s, 3H), 2.55 (dd, J = 5.1, 2.7, 1H), 2.70 (dd, J = 4.4, 4.4, 1H), 2.86 (dd, J = 13.7, 5.9, 1H), 3.10 (dd, J = 13.7, 4.9, 1H), 3.18 – 3.19 (m, 1H), 3.81 (s, 3H), 5.09 (s, 2H). 13C NMR (CDCl3, δ): -3.35, -3.23, 1.25, 11.74, 18.98, 26.26, 27.92, 47.41, 51.29, 61.30, 67.93, 111.99, 118.31, 123.41, 147.18, 152.44, 163.72, 169.25. MS: C19H28O5Si M/z = 364.3 (calculated 364.2) NMR spectra were recorded with Varian Unity Plus 500 MHz. Coupling constants are given in Hz. Mass spectrum was recorded with MALDI-TOF spectrometer BRUKER BIFLEX III (DHB matrix).Column chromatography was carried out on silica gel Merck 60 (0.063–0.2 mm). The reactions were followed with TLC technique on plates Merck 60 F254. All solvents were purified according to standard methods. |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Si1 | 0.75384 (6) | 0.75814 (4) | 0.80053 (2) | 0.02184 (17) | |
O1 | 0.74792 (15) | 0.71310 (10) | 0.87721 (6) | 0.0229 (3) | |
O2 | 0.42666 (18) | 0.41649 (10) | 0.87895 (6) | 0.0306 (3) | |
O3 | 0.67752 (19) | 0.46983 (11) | 0.83748 (7) | 0.0370 (4) | |
O4 | 0.31864 (16) | 0.82981 (10) | 1.02105 (6) | 0.0268 (3) | |
C1 | 0.6018 (2) | 0.69206 (14) | 0.91006 (8) | 0.0208 (4) | |
C2 | 0.5145 (2) | 0.59172 (14) | 0.90497 (8) | 0.0220 (4) | |
C3 | 0.3654 (2) | 0.57202 (14) | 0.93807 (8) | 0.0228 (4) | |
C4 | 0.2933 (2) | 0.64859 (14) | 0.97795 (8) | 0.0233 (4) | |
C5 | 0.3860 (2) | 0.74744 (14) | 0.98426 (8) | 0.0226 (4) | |
C6 | 0.5399 (2) | 0.77006 (13) | 0.95246 (8) | 0.0210 (4) | |
C7 | 0.6395 (2) | 0.87568 (14) | 0.96487 (9) | 0.0265 (4) | |
H7A | 0.6557 | 0.912 | 0.9229 | 0.032* | |
H7B | 0.5679 | 0.9247 | 0.9907 | 0.032* | |
C8 | 0.1239 (18) | 0.6273 (9) | 1.0104 (6) | 0.0328 (8) | 0.839 (5) |
H8A | 0.0916 | 0.6925 | 1.0343 | 0.049* | 0.839 (5) |
H8B | 0.1415 | 0.5658 | 1.0405 | 0.049* | 0.839 (5) |
H8C | 0.0289 | 0.6097 | 0.9774 | 0.049* | 0.839 (5) |
C8A | 0.128 (10) | 0.628 (5) | 1.007 (3) | 0.0328 (8) | 0.161 (5) |
H8D | 0.0882 | 0.5537 | 0.9972 | 0.049* | 0.161 (5) |
H8E | 0.0385 | 0.6803 | 0.9905 | 0.049* | 0.161 (5) |
H8F | 0.1467 | 0.6366 | 1.0545 | 0.049* | 0.161 (5) |
C9 | 0.3019 (3) | 0.45817 (14) | 0.92251 (9) | 0.0276 (4) | |
H9A | 0.3025 | 0.4131 | 0.9623 | 0.033* | |
H9B | 0.1805 | 0.4592 | 0.9014 | 0.033* | |
C10 | 0.5564 (3) | 0.49177 (15) | 0.86926 (9) | 0.0272 (4) | |
C11 | 0.3706 (5) | 0.8213 (3) | 1.08945 (13) | 0.0311 (7) | 0.839 (5) |
H11A | 0.4995 | 0.8286 | 1.0962 | 0.047* | 0.839 (5) |
H11B | 0.3342 | 0.7501 | 1.1056 | 0.047* | 0.839 (5) |
H11C | 0.3133 | 0.8794 | 1.1129 | 0.047* | 0.839 (5) |
C11A | 0.304 (2) | 0.8127 (17) | 1.0872 (10) | 0.035 (5)* | 0.161 (5) |
H11D | 0.2542 | 0.8781 | 1.1064 | 0.052* | 0.161 (5) |
H11E | 0.4211 | 0.7976 | 1.1083 | 0.052* | 0.161 (5) |
H11F | 0.2254 | 0.7504 | 1.0933 | 0.052* | 0.161 (5) |
O5 | 0.8139 (2) | 0.82094 (13) | 1.06596 (7) | 0.0447 (4) | |
C12 | 0.8155 (3) | 0.85929 (19) | 0.99979 (11) | 0.0303 (7) | 0.839 (5) |
H12 | 0.9079 | 0.826 | 0.9737 | 0.036* | 0.839 (5) |
C12A | 0.7066 (14) | 0.8869 (9) | 1.0375 (5) | 0.029 (3)* | 0.161 (5) |
H12A | 0.6155 | 0.916 | 1.0657 | 0.034* | 0.161 (5) |
C13 | 0.8822 (3) | 0.9282 (2) | 1.05370 (11) | 0.0482 (6) | |
H13A | 1.0118 | 0.9393 | 1.0599 | 0.058* | |
H13B | 0.8097 | 0.9918 | 1.0649 | 0.058* | |
C14 | 0.6788 (3) | 0.90278 (17) | 0.79575 (10) | 0.0375 (5) | |
H14A | 0.7587 | 0.948 | 0.8238 | 0.056* | |
H14B | 0.5583 | 0.908 | 0.81 | 0.056* | |
H14C | 0.68 | 0.9285 | 0.7509 | 0.056* | |
C15 | 0.6074 (3) | 0.67721 (18) | 0.74361 (9) | 0.0366 (5) | |
H15A | 0.4865 | 0.6782 | 0.7578 | 0.055* | |
H15B | 0.6501 | 0.6017 | 0.7428 | 0.055* | |
H15C | 0.6078 | 0.7088 | 0.7001 | 0.055* | |
C16 | 0.9937 (2) | 0.74546 (15) | 0.78426 (9) | 0.0259 (4) | |
C17 | 1.1085 (3) | 0.81497 (18) | 0.83260 (10) | 0.0382 (5) | |
H17A | 1.0757 | 0.892 | 0.8273 | 0.057* | |
H17B | 1.2336 | 0.8057 | 0.8245 | 0.057* | |
H17C | 1.0894 | 0.7916 | 0.8769 | 0.057* | |
C18 | 1.0503 (3) | 0.62553 (18) | 0.79128 (13) | 0.0440 (6) | |
H18A | 1.1764 | 0.6189 | 0.7841 | 0.066* | |
H18B | 0.9809 | 0.5812 | 0.7593 | 0.066* | |
H18C | 1.0296 | 0.5998 | 0.835 | 0.066* | |
C19 | 1.0203 (3) | 0.7855 (2) | 0.71551 (10) | 0.0414 (5) | |
H19A | 0.9473 | 0.7417 | 0.6843 | 0.062* | |
H19B | 1.1453 | 0.778 | 0.7067 | 0.062* | |
H19C | 0.9853 | 0.8623 | 0.7115 | 0.062* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Si1 | 0.0212 (3) | 0.0250 (3) | 0.0195 (3) | 0.00013 (19) | 0.00251 (19) | 0.00215 (19) |
O1 | 0.0221 (6) | 0.0270 (6) | 0.0202 (6) | 0.0007 (5) | 0.0055 (5) | 0.0011 (5) |
O2 | 0.0433 (8) | 0.0202 (6) | 0.0289 (7) | −0.0026 (6) | 0.0072 (6) | −0.0032 (5) |
O3 | 0.0470 (9) | 0.0279 (7) | 0.0381 (8) | 0.0057 (6) | 0.0169 (7) | −0.0044 (6) |
O4 | 0.0317 (7) | 0.0235 (6) | 0.0259 (7) | 0.0063 (5) | 0.0061 (5) | −0.0033 (5) |
C1 | 0.0226 (9) | 0.0226 (9) | 0.0173 (8) | 0.0013 (7) | 0.0015 (7) | 0.0030 (7) |
C2 | 0.0269 (9) | 0.0220 (9) | 0.0171 (8) | 0.0043 (7) | 0.0010 (7) | 0.0012 (7) |
C3 | 0.0263 (9) | 0.0221 (9) | 0.0200 (9) | −0.0014 (7) | −0.0001 (7) | 0.0031 (7) |
C4 | 0.0234 (9) | 0.0241 (9) | 0.0226 (9) | 0.0022 (7) | 0.0025 (7) | 0.0029 (7) |
C5 | 0.0269 (9) | 0.0208 (9) | 0.0200 (9) | 0.0062 (7) | 0.0022 (7) | 0.0006 (7) |
C6 | 0.0241 (9) | 0.0195 (8) | 0.0193 (9) | 0.0009 (7) | 0.0009 (7) | 0.0015 (7) |
C7 | 0.0348 (10) | 0.0197 (9) | 0.0256 (10) | −0.0026 (7) | 0.0063 (8) | −0.0024 (7) |
C8 | 0.0308 (12) | 0.0301 (11) | 0.039 (2) | −0.0030 (9) | 0.0112 (12) | −0.0024 (9) |
C8A | 0.0308 (12) | 0.0301 (11) | 0.039 (2) | −0.0030 (9) | 0.0112 (12) | −0.0024 (9) |
C9 | 0.0346 (10) | 0.0236 (9) | 0.0253 (10) | −0.0022 (8) | 0.0056 (8) | −0.0001 (8) |
C10 | 0.0377 (11) | 0.0212 (9) | 0.0231 (9) | 0.0015 (8) | 0.0037 (8) | 0.0001 (7) |
C11 | 0.0414 (19) | 0.0319 (15) | 0.0207 (13) | 0.0061 (15) | 0.0065 (14) | −0.0039 (10) |
O5 | 0.0453 (9) | 0.0544 (10) | 0.0332 (8) | 0.0020 (7) | −0.0055 (7) | 0.0002 (7) |
C12 | 0.0284 (13) | 0.0305 (13) | 0.0321 (13) | −0.0021 (10) | 0.0025 (10) | −0.0054 (10) |
C13 | 0.0406 (12) | 0.0521 (14) | 0.0503 (14) | −0.0084 (11) | −0.0072 (11) | −0.0174 (11) |
C14 | 0.0444 (12) | 0.0354 (11) | 0.0334 (11) | 0.0099 (9) | 0.0070 (9) | 0.0085 (9) |
C15 | 0.0345 (11) | 0.0476 (12) | 0.0269 (10) | −0.0115 (9) | −0.0037 (8) | 0.0061 (9) |
C16 | 0.0228 (9) | 0.0308 (10) | 0.0247 (10) | −0.0026 (7) | 0.0054 (7) | −0.0025 (8) |
C17 | 0.0262 (10) | 0.0504 (13) | 0.0378 (12) | −0.0071 (9) | 0.0000 (9) | −0.0083 (10) |
C18 | 0.0325 (11) | 0.0380 (12) | 0.0630 (15) | 0.0085 (9) | 0.0140 (10) | −0.0017 (11) |
C19 | 0.0405 (12) | 0.0563 (13) | 0.0291 (11) | −0.0124 (10) | 0.0147 (9) | −0.0018 (10) |
Si1—O1 | 1.6832 (12) | C11—H11A | 0.98 |
Si1—C15 | 1.849 (2) | C11—H11B | 0.98 |
Si1—C14 | 1.861 (2) | C11—H11C | 0.98 |
Si1—C16 | 1.8756 (19) | C11A—H11D | 0.98 |
O1—C1 | 1.363 (2) | C11A—H11E | 0.98 |
O2—C10 | 1.372 (2) | C11A—H11F | 0.98 |
O2—C9 | 1.443 (2) | O5—C12A | 1.262 (11) |
O3—C10 | 1.196 (2) | O5—C13 | 1.440 (3) |
O4—C5 | 1.382 (2) | O5—C12 | 1.448 (3) |
O4—C11A | 1.40 (2) | C12—C13 | 1.460 (3) |
O4—C11 | 1.446 (3) | C12—H12 | 1 |
C1—C2 | 1.396 (2) | C12A—C13 | 1.439 (10) |
C1—C6 | 1.400 (2) | C12A—H12A | 1 |
C2—C3 | 1.381 (2) | C13—H13A | 0.99 |
C2—C10 | 1.476 (2) | C13—H13B | 0.99 |
C3—C4 | 1.386 (2) | C14—H14A | 0.98 |
C3—C9 | 1.502 (2) | C14—H14B | 0.98 |
C4—C5 | 1.401 (3) | C14—H14C | 0.98 |
C4—C8A | 1.45 (8) | C15—H15A | 0.98 |
C4—C8 | 1.510 (15) | C15—H15B | 0.98 |
C5—C6 | 1.405 (2) | C15—H15C | 0.98 |
C6—C7 | 1.510 (2) | C16—C19 | 1.531 (3) |
C7—C12 | 1.484 (3) | C16—C18 | 1.534 (3) |
C7—C12A | 1.559 (10) | C16—C17 | 1.536 (3) |
C7—H7A | 0.99 | C17—H17A | 0.98 |
C7—H7B | 0.99 | C17—H17B | 0.98 |
C8—H8A | 0.98 | C17—H17C | 0.98 |
C8—H8B | 0.98 | C18—H18A | 0.98 |
C8—H8C | 0.98 | C18—H18B | 0.98 |
C8A—H8D | 0.98 | C18—H18C | 0.98 |
C8A—H8E | 0.98 | C19—H19A | 0.98 |
C8A—H8F | 0.98 | C19—H19B | 0.98 |
C9—H9A | 0.99 | C19—H19C | 0.98 |
C9—H9B | 0.99 | ||
O1—Si1—C15 | 111.75 (8) | O4—C11A—H11E | 109.5 |
O1—Si1—C14 | 109.52 (8) | H11D—C11A—H11E | 109.5 |
C15—Si1—C14 | 108.02 (10) | O4—C11A—H11F | 109.5 |
O1—Si1—C16 | 103.39 (7) | H11D—C11A—H11F | 109.5 |
C15—Si1—C16 | 112.72 (9) | H11E—C11A—H11F | 109.5 |
C14—Si1—C16 | 111.40 (9) | C12A—O5—C13 | 63.9 (5) |
C1—O1—Si1 | 127.45 (11) | C12A—O5—C12 | 53.0 (5) |
C10—O2—C9 | 111.07 (13) | C13—O5—C12 | 60.73 (14) |
C5—O4—C11A | 119.2 (9) | O5—C12—C13 | 59.37 (15) |
C5—O4—C11 | 113.62 (16) | O5—C12—C7 | 115.98 (18) |
O1—C1—C2 | 121.69 (15) | C13—C12—C7 | 123.0 (2) |
O1—C1—C6 | 120.15 (15) | O5—C12—H12 | 115.5 |
C2—C1—C6 | 118.10 (16) | C13—C12—H12 | 115.5 |
C3—C2—C1 | 121.01 (16) | C7—C12—H12 | 115.5 |
C3—C2—C10 | 108.34 (15) | O5—C12A—C13 | 64.1 (5) |
C1—C2—C10 | 130.62 (16) | O5—C12A—C7 | 123.3 (8) |
C2—C3—C4 | 123.09 (16) | C13—C12A—C7 | 119.3 (7) |
C2—C3—C9 | 108.42 (15) | O5—C12A—H12A | 113.8 |
C4—C3—C9 | 128.48 (16) | C13—C12A—H12A | 113.8 |
C3—C4—C5 | 115.14 (16) | C7—C12A—H12A | 113.8 |
C3—C4—C8A | 121 (2) | O5—C12A—H13B | 93.9 |
C5—C4—C8A | 123 (2) | C7—C12A—H13B | 122.4 |
C3—C4—C8 | 121.9 (5) | H12A—C12A—H13B | 81.1 |
C5—C4—C8 | 122.9 (5) | C12A—C13—O5 | 52.0 (5) |
O4—C5—C4 | 118.72 (15) | C12A—C13—C12 | 49.8 (5) |
O4—C5—C6 | 117.61 (15) | O5—C13—C12 | 59.90 (14) |
C4—C5—C6 | 123.58 (16) | O5—C13—H13A | 117.8 |
C1—C6—C5 | 118.91 (15) | C12—C13—H13A | 117.8 |
C1—C6—C7 | 120.43 (15) | C12A—C13—H13B | 79.2 |
C5—C6—C7 | 120.65 (15) | O5—C13—H13B | 117.7 |
C12—C7—C6 | 112.79 (16) | C12—C13—H13B | 117.8 |
C12—C7—C12A | 47.3 (4) | H13A—C13—H13B | 114.9 |
C6—C7—C12A | 111.4 (4) | Si1—C14—H14A | 109.5 |
C12—C7—H7A | 109 | Si1—C14—H14B | 109.5 |
C6—C7—H7A | 109 | H14A—C14—H14B | 109.5 |
C12A—C7—H7A | 138.9 | Si1—C14—H14C | 109.5 |
C12—C7—H7B | 109 | H14A—C14—H14C | 109.5 |
C6—C7—H7B | 109 | H14B—C14—H14C | 109.5 |
C12A—C7—H7B | 65.2 | Si1—C15—H15A | 109.5 |
H7A—C7—H7B | 107.8 | Si1—C15—H15B | 109.5 |
C4—C8—H8A | 109.5 | H15A—C15—H15B | 109.5 |
C4—C8—H8B | 109.5 | Si1—C15—H15C | 109.5 |
H8A—C8—H8B | 109.5 | H15A—C15—H15C | 109.5 |
C4—C8—H8C | 109.5 | H15B—C15—H15C | 109.5 |
H8A—C8—H8C | 109.5 | C19—C16—C18 | 109.91 (17) |
H8B—C8—H8C | 109.5 | C19—C16—C17 | 108.83 (16) |
C4—C8A—H8D | 109.5 | C18—C16—C17 | 109.13 (17) |
C4—C8A—H8E | 109.5 | C19—C16—Si1 | 109.37 (13) |
H8D—C8A—H8E | 109.5 | C18—C16—Si1 | 109.24 (13) |
C4—C8A—H8F | 109.5 | C17—C16—Si1 | 110.36 (13) |
H8D—C8A—H8F | 109.5 | C16—C17—H17A | 109.5 |
H8E—C8A—H8F | 109.5 | C16—C17—H17B | 109.5 |
O2—C9—C3 | 104.40 (14) | H17A—C17—H17B | 109.5 |
O2—C9—H9A | 110.9 | C16—C17—H17C | 109.5 |
C3—C9—H9A | 110.9 | H17A—C17—H17C | 109.5 |
O2—C9—H9B | 110.9 | H17B—C17—H17C | 109.5 |
C3—C9—H9B | 110.9 | C16—C18—H18A | 109.5 |
H9A—C9—H9B | 108.9 | C16—C18—H18B | 109.5 |
O3—C10—O2 | 120.90 (16) | H18A—C18—H18B | 109.5 |
O3—C10—C2 | 131.42 (18) | C16—C18—H18C | 109.5 |
O2—C10—C2 | 107.67 (15) | H18A—C18—H18C | 109.5 |
O4—C11—H11A | 109.5 | H18B—C18—H18C | 109.5 |
O4—C11—H11B | 109.5 | C16—C19—H19A | 109.5 |
H11A—C11—H11B | 109.5 | C16—C19—H19B | 109.5 |
O4—C11—H11C | 109.5 | H19A—C19—H19B | 109.5 |
H11A—C11—H11C | 109.5 | C16—C19—H19C | 109.5 |
H11B—C11—H11C | 109.5 | H19A—C19—H19C | 109.5 |
O4—C11A—H11D | 109.5 | H19B—C19—H19C | 109.5 |
C15—Si1—O1—C1 | −49.33 (16) | C10—O2—C9—C3 | 1.70 (19) |
C14—Si1—O1—C1 | 70.33 (16) | C2—C3—C9—O2 | 0.31 (19) |
C16—Si1—O1—C1 | −170.83 (14) | C4—C3—C9—O2 | −179.97 (16) |
Si1—O1—C1—C2 | 85.05 (19) | C9—O2—C10—O3 | 175.75 (17) |
Si1—O1—C1—C6 | −97.84 (17) | C9—O2—C10—C2 | −2.94 (19) |
O1—C1—C2—C3 | −179.33 (15) | C3—C2—C10—O3 | −175.4 (2) |
C6—C1—C2—C3 | 3.5 (2) | C1—C2—C10—O3 | 2.7 (3) |
O1—C1—C2—C10 | 2.8 (3) | C3—C2—C10—O2 | 3.1 (2) |
C6—C1—C2—C10 | −174.42 (17) | C1—C2—C10—O2 | −178.78 (16) |
C1—C2—C3—C4 | −0.1 (3) | C12A—O5—C12—C13 | 78.0 (6) |
C10—C2—C3—C4 | 178.22 (16) | C12A—O5—C12—C7 | −36.6 (6) |
C1—C2—C3—C9 | 179.64 (15) | C13—O5—C12—C7 | −114.6 (2) |
C10—C2—C3—C9 | −2.03 (19) | C6—C7—C12—O5 | −67.0 (2) |
C2—C3—C4—C5 | −2.0 (3) | C12A—C7—C12—O5 | 31.7 (6) |
C9—C3—C4—C5 | 178.31 (17) | C6—C7—C12—C13 | −136.0 (2) |
C2—C3—C4—C8A | 175 (3) | C12A—C7—C12—C13 | −37.3 (6) |
C9—C3—C4—C8A | −5 (3) | C12—O5—C12A—C13 | −71.7 (4) |
C2—C3—C4—C8 | 176.3 (5) | C13—O5—C12A—C7 | 109.4 (9) |
C9—C3—C4—C8 | −3.4 (6) | C12—O5—C12A—C7 | 37.6 (6) |
C11A—O4—C5—C4 | 63.1 (9) | C12—C7—C12A—O5 | −40.4 (6) |
C11—O4—C5—C4 | 85.5 (2) | C6—C7—C12A—O5 | 61.4 (9) |
C11A—O4—C5—C6 | −120.1 (9) | C12—C7—C12A—C13 | 36.2 (5) |
C11—O4—C5—C6 | −97.7 (2) | C6—C7—C12A—C13 | 138.0 (7) |
C3—C4—C5—O4 | 177.35 (15) | C7—C12A—C13—O5 | −115.3 (10) |
C8A—C4—C5—O4 | 1 (3) | O5—C12A—C13—C12 | 80.0 (5) |
C8—C4—C5—O4 | −0.9 (6) | C7—C12A—C13—C12 | −35.3 (5) |
C3—C4—C5—C6 | 0.8 (3) | C12—O5—C13—C12A | 60.4 (6) |
C8A—C4—C5—C6 | −176 (3) | C12A—O5—C13—C12 | −60.4 (6) |
C8—C4—C5—C6 | −177.5 (6) | O5—C12—C13—C12A | −63.8 (6) |
O1—C1—C6—C5 | 178.18 (14) | C7—C12—C13—C12A | 39.1 (6) |
C2—C1—C6—C5 | −4.6 (2) | C7—C12—C13—O5 | 102.8 (2) |
O1—C1—C6—C7 | −3.2 (2) | O1—Si1—C16—C19 | −179.28 (13) |
C2—C1—C6—C7 | 174.04 (15) | C15—Si1—C16—C19 | 59.87 (16) |
O4—C5—C6—C1 | −174.07 (15) | C14—Si1—C16—C19 | −61.75 (16) |
C4—C5—C6—C1 | 2.6 (3) | O1—Si1—C16—C18 | 60.38 (15) |
O4—C5—C6—C7 | 7.3 (2) | C15—Si1—C16—C18 | −60.46 (17) |
C4—C5—C6—C7 | −176.07 (16) | C14—Si1—C16—C18 | 177.91 (14) |
C1—C6—C7—C12 | −66.9 (2) | O1—Si1—C16—C17 | −59.59 (15) |
C5—C6—C7—C12 | 111.68 (19) | C15—Si1—C16—C17 | 179.56 (14) |
C1—C6—C7—C12A | −118.2 (5) | C14—Si1—C16—C17 | 57.94 (16) |
C5—C6—C7—C12A | 60.4 (5) |
Experimental details
Crystal data | |
Chemical formula | C19H28O5Si |
Mr | 364.5 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 120 |
a, b, c (Å) | 7.5682 (3), 12.2488 (4), 20.6905 (8) |
β (°) | 93.990 (4) |
V (Å3) | 1913.39 (12) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.15 |
Crystal size (mm) | 0.55 × 0.44 × 0.35 |
Data collection | |
Diffractometer | Agilent Xcalibur |
Absorption correction | Analytical (Clark & Reid, 1995) |
Tmin, Tmax | 0.938, 0.954 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6727, 3430, 2858 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.599 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.123, 1.09 |
No. of reflections | 3430 |
No. of parameters | 243 |
No. of restraints | 2 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.42, −0.18 |
Computer programs: CrysAlis PRO (Agilent, 2010), SUPERFLIP (Palatinus & Chapuis, 2007), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997), publCIF (Westrip, 2010), PLATON (Spek, 2009), WinGX (Farrugia, 1999) and Mercury (Macrae et al., 2006).
Acknowledgements
We would like to thank the National Centre for Research and Development (Poland) for financial support (grant No. LIDER/07/581L-2/10/NCBiR/2011)
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Presented research is an attempt to modify the known multi-stage total synthesis of mycophenolic acid (Patterson, 1995) by making use of epoxides as intermediates. The synthesis of the desired epoxide was successful and its X-ray structure has been determined.
In the title compound, bond length C12—C13 is ca 0.01 Å longer than C12—O5 or C13—O5, which is a trend noted for other oxirans. The valence angle at O5 is close to the average of 60.5 (9)° calculated for 17 structures containing benzyloxirane fragment, according to our CSD search (Allen et al., 2002). The most closely related compounds, which contain the 1-phenyl-2,3-epoxypropane fragment are rac-3-(9-anthryl)-1,2-epoxypropane (Langer et al., 1993) and a modified calix[4]arene (Berthalon et al., 1999).
The crystal lattice is composed of discrete molecules with no strong specific intermolecular interactions. The strongest stacking interaction is found between the benzene and furan rings of molecules related by the inversion at (1/2, 1/2, 1) with a distance of 3.8773 (13) Å between the ring centroids.
The ORTEP view of the title epoxide is given in Fig. 1. Although the oxirane ring is not connected with the aromatic ring directly, the shortest intramolecular contact between the ring and adjacent methoxy substituent is rather short 2.560 (3) Å for O5···H11A. Epoxides are known to be reactive compounds (Padwa et al., 2006), but the investigated oxirane is relatively stable and can be purified on silica gel and stored for several months. We suppose the reactivity of the epoxide ring is decreased by the steric hindrance from the proximate methoxyl and t-BuMe2Si substituents.