organic compounds
Benzene-1,3,5-triyl tris(2,2-dimethylpropanoate)
aSchool of Chemistry, University of East Anglia, Norwich NR4 7TJ, England
*Correspondence e-mail: d.l.hughes@uea.ac.uk
In the title compound, C21H30O6, the three acetoxy groups are essentially planar with their normals rotated by −57.75 (4), −62.36 (4) and 63.36 (4)° from the normal to the mean plane of the C6 ring. The arrangement of carbonyl groups around the ring is of two groups `up' and one `down', and the propeller-style arrangement of substituent groups is spoiled with the plane of the `down' group twisted in the opposite direction; all the Cring—O—C—CMe3 conformations are trans. In the crystal, aromatic π–π stacking occurs [centroid–centroid separation = 3.320 (1) Å]; the other main intermolecular interaction is a C—H⋯π-ring contact on the opposing side from the overlapped ring pairing; there are no short C—H⋯O contacts.
Related literature
For our previous studies in this area, see: Haines & Hughes (2007); Haines et al. (2008, 2009). For a related structure, see: Haines & Hughes (2009). For furhter synthetic details, see: Hegetschweiler et al. (1990).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlisPro CCD (Oxford Diffraction, 2008); cell CrysAlisPro RED (Oxford Diffraction, 2008); data reduction: CrysAlisPro RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536809050028/hb5166sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809050028/hb5166Isup2.hkl
The title compound was prepared by conventional acylation of the parent 1,3,5-trihydroxybenzene and gave analytical data (HRMS) and spectral data (1H and 13C NMR) in full accord with the expected structure.
1,3,5-Tris-(trimethylacetoxy)benzene (1) - 1,3,5-Trihydroxybenzene (0.63 g) was dissolved in pyridine (6 ml), trimethylacetyl chloride (3.7 ml) was added, and the mixture was then stored for 12 h at room temperature. Water (1 ml) was added to destroy excess acyl chloride, and the mixture was then poured on to ice, affording a sticky solid which was separated and dissolved in dichloromethane (30 ml). This solution was washed with saturated aqueous sodium hydrogen carbonate, water, and then dried over anhydrous sodium sulfate. Concentration of the filtered solution gave a crystalline solid which was recrystallized from ethanol to give compound 1 (0.947 g, 50%), m.p. 163–165 °C; δH(CDCl3) 6.77, (s, 3H), 1.33 (s, 27H); δC (CDCl3) 176.43, 151.68, 112.57, 39.02, 26.91. m/z (ES): 396.2 [M+NH4]+. (Found: [M+NH4]+ 396.2381. C21H34NO6 requires m/z 396.2381).
Hydrogen atoms were included in idealized positions and their Uiso values were set to ride on the Ueq values of the parent carbon atoms.
Data collection: CrysAlis PRO CCD (Oxford Diffraction, 2008); cell
CrysAlis PRO RED (Oxford Diffraction, 2008); data reduction: CrysAlis PRO RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).C21H30O6 | V = 1068.87 (5) Å3 |
Mr = 378.45 | Z = 2 |
Triclinic, P1 | F(000) = 408 |
Hall symbol: -P 1 | Dx = 1.176 Mg m−3 |
a = 9.4812 (3) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 10.6885 (3) Å | µ = 0.09 mm−1 |
c = 11.4799 (3) Å | T = 140 K |
α = 91.138 (2)° | Plate, colourless |
β = 97.649 (3)° | 0.65 × 0.32 × 0.15 mm |
γ = 111.624 (3)° |
Oxford Diffraction Xcalibur 3/CCD diffractometer | 6205 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 4605 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.038 |
Detector resolution: 16.0050 pixels mm-1 | θmax = 30.0°, θmin = 3.2° |
Thin–slice ϕ and ω scans | h = −13→13 |
Absorption correction: multi-scan (CrysAlis PRO RED; Oxford Diffraction, 2008) | k = −15→15 |
Tmin = 0.920, Tmax = 1.059 | l = −16→16 |
26503 measured reflections |
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)] = 0.047 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.132 | H-atom parameters constrained |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0693P)2 + 0.1174P] where P = (Fo2 + 2Fc2)/3 |
6205 reflections | (Δ/σ)max < 0.001 |
244 parameters | Δρmax = 0.65 e Å−3 |
0 restraints | Δρmin = −0.34 e Å−3 |
C21H30O6 | γ = 111.624 (3)° |
Mr = 378.45 | V = 1068.87 (5) Å3 |
Triclinic, P1 | Z = 2 |
a = 9.4812 (3) Å | Mo Kα radiation |
b = 10.6885 (3) Å | µ = 0.09 mm−1 |
c = 11.4799 (3) Å | T = 140 K |
α = 91.138 (2)° | 0.65 × 0.32 × 0.15 mm |
β = 97.649 (3)° |
Oxford Diffraction Xcalibur 3/CCD diffractometer | 6205 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO RED; Oxford Diffraction, 2008) | 4605 reflections with I > 2σ(I) |
Tmin = 0.920, Tmax = 1.059 | Rint = 0.038 |
26503 measured reflections |
R[F2 > 2σ(F2)] = 0.047 | 0 restraints |
wR(F2) = 0.132 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.65 e Å−3 |
6205 reflections | Δρmin = −0.34 e Å−3 |
244 parameters |
Experimental. CrysAlisPro RED, Oxford Diffraction Ltd., Version 1.171.32.24 Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.27936 (13) | 0.48381 (12) | 0.50299 (10) | 0.0183 (2) | |
C2 | 0.39408 (13) | 0.61026 (12) | 0.50434 (10) | 0.0187 (2) | |
H2 | 0.3990 | 0.6620 | 0.4397 | 0.022* | |
C3 | 0.50064 (13) | 0.65635 (11) | 0.60527 (10) | 0.0185 (2) | |
C4 | 0.49732 (13) | 0.58123 (12) | 0.70237 (10) | 0.0193 (2) | |
H4 | 0.5708 | 0.6140 | 0.7693 | 0.023* | |
C5 | 0.38065 (13) | 0.45569 (12) | 0.69610 (10) | 0.0183 (2) | |
C6 | 0.26969 (13) | 0.40486 (12) | 0.59784 (10) | 0.0191 (2) | |
H6 | 0.1914 | 0.3206 | 0.5956 | 0.023* | |
O1 | 0.17567 (10) | 0.42434 (8) | 0.40037 (7) | 0.02236 (19) | |
C11 | 0.08728 (12) | 0.49094 (12) | 0.34944 (10) | 0.0182 (2) | |
O11 | 0.08760 (11) | 0.59371 (9) | 0.39219 (8) | 0.0276 (2) | |
C12 | −0.01207 (13) | 0.41230 (12) | 0.23672 (10) | 0.0194 (2) | |
C13 | −0.14944 (15) | 0.29840 (14) | 0.27447 (13) | 0.0293 (3) | |
H13A | −0.2155 | 0.2458 | 0.2058 | 0.044* | |
H13B | −0.2056 | 0.3368 | 0.3178 | 0.044* | |
H13C | −0.1129 | 0.2416 | 0.3234 | 0.044* | |
C14 | 0.07752 (16) | 0.35349 (16) | 0.16576 (12) | 0.0313 (3) | |
H14A | 0.0122 | 0.3041 | 0.0955 | 0.047* | |
H14B | 0.1123 | 0.2940 | 0.2125 | 0.047* | |
H14C | 0.1644 | 0.4254 | 0.1447 | 0.047* | |
C15 | −0.06716 (15) | 0.50707 (14) | 0.16204 (11) | 0.0272 (3) | |
H15A | −0.1303 | 0.4582 | 0.0908 | 0.041* | |
H15B | 0.0199 | 0.5802 | 0.1427 | 0.041* | |
H15C | −0.1257 | 0.5423 | 0.2057 | 0.041* | |
O3 | 0.62184 (10) | 0.78028 (9) | 0.60186 (8) | 0.0246 (2) | |
C31 | 0.63776 (14) | 0.88421 (12) | 0.67938 (11) | 0.0236 (2) | |
O31 | 0.55553 (14) | 0.87315 (11) | 0.75191 (10) | 0.0443 (3) | |
C32 | 0.77047 (16) | 1.01112 (13) | 0.65958 (12) | 0.0296 (3) | |
C33 | 0.9154 (2) | 0.9794 (2) | 0.6641 (3) | 0.0782 (8) | |
H33A | 0.9998 | 1.0594 | 0.6518 | 0.117* | |
H33B | 0.8997 | 0.9103 | 0.6036 | 0.117* | |
H33C | 0.9379 | 0.9487 | 0.7397 | 0.117* | |
C34 | 0.7314 (3) | 1.05974 (18) | 0.54077 (15) | 0.0601 (6) | |
H34A | 0.8148 | 1.1401 | 0.5277 | 0.090* | |
H34B | 0.6400 | 1.0790 | 0.5397 | 0.090* | |
H34C | 0.7147 | 0.9909 | 0.4797 | 0.090* | |
C35 | 0.7955 (3) | 1.11854 (17) | 0.75681 (16) | 0.0604 (6) | |
H35A | 0.8793 | 1.1992 | 0.7450 | 0.091* | |
H35B | 0.8189 | 1.0867 | 0.8317 | 0.091* | |
H35C | 0.7040 | 1.1378 | 0.7553 | 0.091* | |
O5 | 0.37241 (10) | 0.38397 (9) | 0.79761 (7) | 0.02357 (19) | |
C51 | 0.39004 (16) | 0.26392 (14) | 0.79296 (11) | 0.0259 (3) | |
O51 | 0.40977 (19) | 0.21582 (13) | 0.70459 (10) | 0.0585 (4) | |
C52 | 0.38396 (14) | 0.20385 (13) | 0.91138 (10) | 0.0224 (2) | |
C53 | 0.54114 (17) | 0.27468 (17) | 0.98640 (13) | 0.0378 (3) | |
H53A | 0.5411 | 0.2383 | 1.0622 | 0.057* | |
H53B | 0.5625 | 0.3696 | 0.9963 | 0.057* | |
H53C | 0.6185 | 0.2606 | 0.9479 | 0.057* | |
C54 | 0.26045 (17) | 0.22568 (16) | 0.97295 (12) | 0.0328 (3) | |
H54A | 0.2584 | 0.1866 | 1.0476 | 0.049* | |
H54B | 0.1622 | 0.1835 | 0.9247 | 0.049* | |
H54C | 0.2833 | 0.3207 | 0.9852 | 0.049* | |
C55 | 0.3493 (2) | 0.05325 (15) | 0.89167 (14) | 0.0373 (3) | |
H55A | 0.3453 | 0.0137 | 0.9661 | 0.056* | |
H55B | 0.4285 | 0.0404 | 0.8547 | 0.056* | |
H55C | 0.2522 | 0.0108 | 0.8418 | 0.056* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0195 (5) | 0.0191 (5) | 0.0172 (5) | 0.0095 (4) | −0.0006 (4) | −0.0011 (4) |
C2 | 0.0228 (5) | 0.0182 (5) | 0.0171 (5) | 0.0094 (4) | 0.0044 (4) | 0.0031 (4) |
C3 | 0.0178 (5) | 0.0159 (5) | 0.0210 (5) | 0.0047 (4) | 0.0051 (4) | −0.0007 (4) |
C4 | 0.0193 (5) | 0.0216 (6) | 0.0176 (5) | 0.0090 (4) | 0.0008 (4) | −0.0011 (4) |
C5 | 0.0233 (5) | 0.0192 (5) | 0.0158 (5) | 0.0112 (4) | 0.0047 (4) | 0.0040 (4) |
C6 | 0.0199 (5) | 0.0156 (5) | 0.0215 (5) | 0.0063 (4) | 0.0028 (4) | 0.0017 (4) |
O1 | 0.0258 (4) | 0.0196 (4) | 0.0206 (4) | 0.0107 (3) | −0.0062 (3) | −0.0025 (3) |
C11 | 0.0172 (5) | 0.0191 (5) | 0.0181 (5) | 0.0063 (4) | 0.0028 (4) | 0.0038 (4) |
O11 | 0.0308 (5) | 0.0224 (5) | 0.0299 (5) | 0.0139 (4) | −0.0048 (4) | −0.0043 (4) |
C12 | 0.0195 (5) | 0.0225 (6) | 0.0164 (5) | 0.0090 (4) | 0.0002 (4) | 0.0000 (4) |
C13 | 0.0239 (6) | 0.0247 (6) | 0.0324 (7) | 0.0024 (5) | 0.0000 (5) | −0.0002 (5) |
C14 | 0.0347 (7) | 0.0423 (8) | 0.0219 (6) | 0.0220 (6) | 0.0007 (5) | −0.0054 (5) |
C15 | 0.0291 (6) | 0.0305 (7) | 0.0218 (6) | 0.0131 (5) | −0.0027 (5) | 0.0036 (5) |
O3 | 0.0235 (4) | 0.0191 (4) | 0.0259 (4) | 0.0005 (3) | 0.0085 (3) | −0.0015 (3) |
C31 | 0.0275 (6) | 0.0184 (6) | 0.0225 (6) | 0.0065 (5) | 0.0019 (5) | 0.0025 (4) |
O31 | 0.0604 (7) | 0.0248 (5) | 0.0460 (6) | 0.0066 (5) | 0.0302 (6) | −0.0023 (5) |
C32 | 0.0330 (7) | 0.0183 (6) | 0.0305 (7) | 0.0016 (5) | 0.0037 (5) | 0.0041 (5) |
C33 | 0.0305 (9) | 0.0388 (11) | 0.153 (2) | −0.0027 (8) | 0.0166 (12) | 0.0135 (13) |
C34 | 0.0894 (15) | 0.0306 (9) | 0.0339 (9) | −0.0049 (9) | −0.0011 (9) | 0.0123 (7) |
C35 | 0.0897 (15) | 0.0251 (8) | 0.0400 (9) | −0.0093 (9) | 0.0119 (10) | −0.0039 (7) |
O5 | 0.0359 (5) | 0.0216 (4) | 0.0175 (4) | 0.0152 (4) | 0.0052 (3) | 0.0049 (3) |
C51 | 0.0360 (7) | 0.0269 (6) | 0.0214 (6) | 0.0181 (6) | 0.0071 (5) | 0.0054 (5) |
O51 | 0.1225 (12) | 0.0528 (8) | 0.0307 (6) | 0.0611 (8) | 0.0299 (7) | 0.0150 (5) |
C52 | 0.0281 (6) | 0.0241 (6) | 0.0177 (5) | 0.0128 (5) | 0.0030 (4) | 0.0057 (4) |
C53 | 0.0311 (7) | 0.0462 (9) | 0.0302 (7) | 0.0096 (6) | −0.0015 (6) | 0.0051 (6) |
C54 | 0.0387 (7) | 0.0405 (8) | 0.0267 (7) | 0.0201 (7) | 0.0140 (6) | 0.0122 (6) |
C55 | 0.0513 (9) | 0.0267 (7) | 0.0374 (8) | 0.0178 (7) | 0.0084 (7) | 0.0069 (6) |
C1—C6 | 1.3829 (16) | C31—C32 | 1.5184 (18) |
C1—C2 | 1.3861 (16) | C32—C35 | 1.516 (2) |
C1—O1 | 1.3999 (14) | C32—C34 | 1.518 (2) |
C2—C3 | 1.3802 (16) | C32—C33 | 1.527 (3) |
C2—H2 | 0.9300 | C33—H33A | 0.9600 |
C3—C4 | 1.3836 (16) | C33—H33B | 0.9600 |
C3—O3 | 1.4032 (14) | C33—H33C | 0.9600 |
C4—C5 | 1.3822 (17) | C34—H34A | 0.9600 |
C4—H4 | 0.9300 | C34—H34B | 0.9600 |
C5—C6 | 1.3830 (16) | C34—H34C | 0.9600 |
C5—O5 | 1.4025 (13) | C35—H35A | 0.9600 |
C6—H6 | 0.9300 | C35—H35B | 0.9600 |
O1—C11 | 1.3699 (13) | C35—H35C | 0.9600 |
C11—O11 | 1.1931 (14) | O5—C51 | 1.3546 (15) |
C11—C12 | 1.5221 (16) | C51—O51 | 1.1955 (16) |
C12—C14 | 1.5289 (17) | C51—C52 | 1.5139 (17) |
C12—C15 | 1.5294 (17) | C52—C55 | 1.5251 (19) |
C12—C13 | 1.5391 (17) | C52—C53 | 1.5286 (19) |
C13—H13A | 0.9600 | C52—C54 | 1.5298 (17) |
C13—H13B | 0.9600 | C53—H53A | 0.9600 |
C13—H13C | 0.9600 | C53—H53B | 0.9600 |
C14—H14A | 0.9600 | C53—H53C | 0.9600 |
C14—H14B | 0.9600 | C54—H54A | 0.9600 |
C14—H14C | 0.9600 | C54—H54B | 0.9600 |
C15—H15A | 0.9600 | C54—H54C | 0.9600 |
C15—H15B | 0.9600 | C55—H55A | 0.9600 |
C15—H15C | 0.9600 | C55—H55B | 0.9600 |
O3—C31 | 1.3601 (15) | C55—H55C | 0.9600 |
C31—O31 | 1.1933 (16) | ||
C6—C1—C2 | 122.36 (11) | C35—C32—C31 | 108.92 (12) |
C6—C1—O1 | 116.42 (10) | C34—C32—C31 | 108.98 (12) |
C2—C1—O1 | 120.95 (10) | C35—C32—C33 | 109.08 (17) |
C3—C2—C1 | 117.42 (10) | C34—C32—C33 | 110.80 (18) |
C3—C2—H2 | 121.3 | C31—C32—C33 | 109.09 (12) |
C1—C2—H2 | 121.3 | C32—C33—H33A | 109.5 |
C2—C3—C4 | 122.69 (11) | C32—C33—H33B | 109.5 |
C2—C3—O3 | 116.51 (10) | H33A—C33—H33B | 109.5 |
C4—C3—O3 | 120.61 (10) | C32—C33—H33C | 109.5 |
C5—C4—C3 | 117.45 (10) | H33A—C33—H33C | 109.5 |
C5—C4—H4 | 121.3 | H33B—C33—H33C | 109.5 |
C3—C4—H4 | 121.3 | C32—C34—H34A | 109.5 |
C4—C5—C6 | 122.43 (10) | C32—C34—H34B | 109.5 |
C4—C5—O5 | 117.03 (10) | H34A—C34—H34B | 109.5 |
C6—C5—O5 | 120.41 (10) | C32—C34—H34C | 109.5 |
C1—C6—C5 | 117.64 (11) | H34A—C34—H34C | 109.5 |
C1—C6—H6 | 121.2 | H34B—C34—H34C | 109.5 |
C5—C6—H6 | 121.2 | C32—C35—H35A | 109.5 |
C11—O1—C1 | 118.78 (9) | C32—C35—H35B | 109.5 |
O11—C11—O1 | 123.06 (11) | H35A—C35—H35B | 109.5 |
O11—C11—C12 | 126.51 (10) | C32—C35—H35C | 109.5 |
O1—C11—C12 | 110.38 (9) | H35A—C35—H35C | 109.5 |
C11—C12—C14 | 111.20 (10) | H35B—C35—H35C | 109.5 |
C11—C12—C15 | 108.90 (10) | C51—O5—C5 | 119.00 (9) |
C14—C12—C15 | 109.33 (10) | O51—C51—O5 | 122.18 (12) |
C11—C12—C13 | 106.60 (10) | O51—C51—C52 | 126.14 (12) |
C14—C12—C13 | 110.37 (11) | O5—C51—C52 | 111.67 (10) |
C15—C12—C13 | 110.40 (10) | C51—C52—C55 | 108.46 (11) |
C12—C13—H13A | 109.5 | C51—C52—C53 | 107.48 (11) |
C12—C13—H13B | 109.5 | C55—C52—C53 | 110.45 (12) |
H13A—C13—H13B | 109.5 | C51—C52—C54 | 110.91 (10) |
C12—C13—H13C | 109.5 | C55—C52—C54 | 109.98 (12) |
H13A—C13—H13C | 109.5 | C53—C52—C54 | 109.53 (11) |
H13B—C13—H13C | 109.5 | C52—C53—H53A | 109.5 |
C12—C14—H14A | 109.5 | C52—C53—H53B | 109.5 |
C12—C14—H14B | 109.5 | H53A—C53—H53B | 109.5 |
H14A—C14—H14B | 109.5 | C52—C53—H53C | 109.5 |
C12—C14—H14C | 109.5 | H53A—C53—H53C | 109.5 |
H14A—C14—H14C | 109.5 | H53B—C53—H53C | 109.5 |
H14B—C14—H14C | 109.5 | C52—C54—H54A | 109.5 |
C12—C15—H15A | 109.5 | C52—C54—H54B | 109.5 |
C12—C15—H15B | 109.5 | H54A—C54—H54B | 109.5 |
H15A—C15—H15B | 109.5 | C52—C54—H54C | 109.5 |
C12—C15—H15C | 109.5 | H54A—C54—H54C | 109.5 |
H15A—C15—H15C | 109.5 | H54B—C54—H54C | 109.5 |
H15B—C15—H15C | 109.5 | C52—C55—H55A | 109.5 |
C31—O3—C3 | 118.41 (9) | C52—C55—H55B | 109.5 |
O31—C31—O3 | 122.71 (12) | H55A—C55—H55B | 109.5 |
O31—C31—C32 | 126.27 (12) | C52—C55—H55C | 109.5 |
O3—C31—C32 | 111.01 (11) | H55A—C55—H55C | 109.5 |
C35—C32—C34 | 109.94 (14) | H55B—C55—H55C | 109.5 |
C6—C1—C2—C3 | −0.10 (17) | O1—C11—C12—C13 | 79.48 (11) |
O1—C1—C2—C3 | −173.88 (10) | C2—C3—O3—C31 | 118.90 (12) |
C1—C2—C3—C4 | 0.68 (17) | C4—C3—O3—C31 | −65.99 (14) |
C1—C2—C3—O3 | 175.68 (9) | C3—O3—C31—O31 | 2.02 (18) |
C2—C3—C4—C5 | −0.51 (17) | C3—O3—C31—C32 | −177.74 (10) |
O3—C3—C4—C5 | −175.32 (10) | O31—C31—C32—C35 | 7.0 (2) |
C3—C4—C5—C6 | −0.24 (17) | O3—C31—C32—C35 | −173.27 (13) |
C3—C4—C5—O5 | −176.02 (10) | O31—C31—C32—C34 | −112.97 (18) |
C2—C1—C6—C5 | −0.59 (17) | O3—C31—C32—C34 | 66.78 (16) |
O1—C1—C6—C5 | 173.45 (10) | O31—C31—C32—C33 | 125.94 (19) |
C4—C5—C6—C1 | 0.77 (17) | O3—C31—C32—C33 | −54.31 (18) |
O5—C5—C6—C1 | 176.41 (10) | C4—C5—O5—C51 | −117.71 (12) |
C6—C1—O1—C11 | 127.36 (11) | C6—C5—O5—C51 | 66.42 (15) |
C2—C1—O1—C11 | −58.51 (14) | C5—O5—C51—O51 | −1.3 (2) |
C1—O1—C11—O11 | −4.65 (16) | C5—O5—C51—C52 | 177.76 (10) |
C1—O1—C11—C12 | 177.63 (10) | O51—C51—C52—C55 | −20.2 (2) |
O11—C11—C12—C14 | 141.50 (13) | O5—C51—C52—C55 | 160.80 (12) |
O1—C11—C12—C14 | −40.87 (13) | O51—C51—C52—C53 | 99.26 (18) |
O11—C11—C12—C15 | 20.96 (17) | O5—C51—C52—C53 | −79.78 (14) |
O1—C11—C12—C15 | −161.40 (9) | O51—C51—C52—C54 | −141.04 (17) |
O11—C11—C12—C13 | −98.15 (14) | O5—C51—C52—C54 | 39.92 (15) |
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13B···Cg1i | 0.96 | 2.82 | 3.7608 (16) | 168 |
Symmetry code: (i) −x, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C21H30O6 |
Mr | 378.45 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 140 |
a, b, c (Å) | 9.4812 (3), 10.6885 (3), 11.4799 (3) |
α, β, γ (°) | 91.138 (2), 97.649 (3), 111.624 (3) |
V (Å3) | 1068.87 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.65 × 0.32 × 0.15 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur 3/CCD diffractometer |
Absorption correction | Multi-scan (CrysAlis PRO RED; Oxford Diffraction, 2008) |
Tmin, Tmax | 0.920, 1.059 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 26503, 6205, 4605 |
Rint | 0.038 |
(sin θ/λ)max (Å−1) | 0.703 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.047, 0.132, 1.08 |
No. of reflections | 6205 |
No. of parameters | 244 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.65, −0.34 |
Computer programs: CrysAlis PRO CCD (Oxford Diffraction, 2008), CrysAlis PRO RED (Oxford Diffraction, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997).
D—H···A | D—H | H···A | D···A | D—H···A |
C13—H13B···Cg1i | 0.96 | 2.82 | 3.7608 (16) | 168 |
Symmetry code: (i) −x, −y+1, −z+1. |
Acknowledgements
We thank the EPSRC National
Service Centre at Swansea for determination of the low and high resolution mass spectra.References
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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.
Structural factors which enhance the solubility of organic compounds in liquid carbon dioxide are difficult to identify, but a knowledge of these is important in view of the possibility of using liquid carbon dioxide as an environmentally acceptable, cheap, safe and readily available alternative to replace organic-based solvents in the development of so-called "green chemistry". Previous studies (Haines et al., 2008) have shown that certain types of acyl group promote the solubilities of per-acylated D-glucopyranose derivatives in liquid carbon dioxide; in particular trimethylacetyl groups promoted solubility, their effect being comparable to acetyl groups and superior to dimethylacetyl groups. In searching for an explanation for solubility differences in this series based on differing intermolecular forces in the solid state, we conducted crystal structure studies on the compounds (Haines & Hughes, 2007), but the results indicated no substantial difference in such intermolecular forces.
Measurement of solubilities in liquid carbon dioxide of 1,3,5-triacetoxybenzene (2) and substituted derivatives, viz 1,3,5-tris-(dimethylacetoxy)benzene (3) and 1,3,5-tris-(trimethylacetoxy)benzene (1), chosen in an attempt to separate the effects on solubility of the number and structure of peripheral substituents in compounds of similar overall molecular dimensions to the carbohydrate derivatives, showed no major differences (Haines, et al., 2009, unpublished results) and prompted an investigation of their crystal structures in order to compare intermolecular interactions in these compounds.
The stucture of the title compound, (1), is shown in Figure 1; compound 2 is described in the preceding paper (Haines and Hughes, 2009). Unfortunately, of the crystals of 3 grown under a variety of conditions, none gave acceptable diffraction patterns, all showing diffuse and blurry diffracted beams and refinement of a disordered structure to rather poor R-values. It is noteworthy that the corresponding dimethylacetyl derivative in the D-glucopyranose series also showed some disorder in its crystalline form. It is also of interest that in both the D-glucopyranose and benzene series, we were unable to crystallize the propionyl derivatives.
Compound 1 was prepared by the acylation of 1,3,5-trihydroxybenzene with trimethylacetyl chloride and formed crystals with molecules arranged in interacting pairs by overlap of the arene rings about a centre of symmetry. C(2) lies over the centre of the opposing ring and is 3.320 (1) Å from the mean-plane of that ring, and C(1) overlaps C(3a) at a distance of 3.326 (2) Å. H(13Bb) is directed towards the centre of the C6 ring from the opposite side and is displaced 2.81 Å from the ring plane; the six H···C distances lie in the range 3.06–3.22 Å; supercripts denote symmetry operations. In contrast to 1,3,5-triacetoxybenzene (2) (previous paper, Haines and Hughes, 2009), there are no intermolecular C—H···O contacts with H···O distances less than 2.55 Å. There are also differences in intramolecular structure from that in 2 in the arrangement of carbonyl groups around the ring. Thus, the three acetoxy groups are essentially planar (as in 2) but have normals rotated -57.75 (4), -62.36 (4) and 63.36 (4)° from the normal to the mean-plane of the C6 ring (in contrast to the three positive angles in 2). Also, the carbonyl O-atoms of two groups here are 'up' and one is 'down' (in contrast to three 'up' in 2), and the propeller-style arrangement of substituent groups is spoiled with the plane of the 'down' group twisted in the opposite direction. In both compounds, all the Cring—O—C—R (R=Me or CMe3) conformations are trans. Dimensions are available in the archived CIFs.