organic compounds
1,2,5-Oxadiazolo[3,4-b]glycyrrhetinic acid
aKey Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China
*Correspondence e-mail: juyong@tsinghua.edu.cn
The title compound [systematic name: 11-oxo-2,3-(oxydinitrilo)olean-12-en-29-oic acid], C30H42N2O4, contains a linear array of five six-membered rings and a five-membered heterocyclic ring. The C ring, containing an α,β-unsaturated ketone, has a slightly distorted half-chair conformation, as does the A ring, with N—C—C angles 125.3 (5), 111.2 (4), 124.9 (5) and 109.2 (5)°, while the other three six-membered rings adopt chair conformations. The enantiomer has been assigned by reference to unchanging chiral centres in the synthetic procedure. An intramolecular C—H⋯O interaction is present. In the intermolecular O—H⋯O hydrogen bonds link the molecules.
Related literature
Glycyrrhetinic acid is the aglycone of glycyrrhizin, a triterpenoid saponin found in the roots of liquorice, see: Yoshida et al. (2001). For the pharmacological activities of glycyrrhetinic acid and its derivatives, see: Finney & Tarknoy (1960); Yu et al. (2006); Su et al. (2004).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: XSCANS (Bruker, 1997); cell XSCANS; data reduction: XSCANS; 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
10.1107/S1600536809020996/at2805sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536809020996/at2805Isup2.hkl
2,3-dihydroxyimino-glycyrrhetinic acid (500 mg, 0.98 mmol), 18-Crown-6 (35 mg, 0.13 mmol) and t-BuOK (220 mg, 1.96 mmol) were dissolved in 15 mL THF and 15 mL DCM. The mixture was stirred for 10 min at 50°C. The product was treated with hydrochloric acid, then washed with H2O and extracted with EtOAc. The combined organic phase was washed with brine, dried and evaporated. Purification by flash chromatography(DCM:Methanol=20:1) gave title compound(439 mg, 91%). Crystals suitable for X-ray structure analysis were obtained via slow evaporation of a solution(chloroform: acetone = 1:7) at room temperature.
All non-hydrogen atoms were subjected to anisotropic
All hydrogen atoms were generated geometrically with O—H bond distance of 0.82 Å and C—H bonds of 0.93–0.98 Å according to criteria described in the SHELXTL manual (Sheldrick, 2008). They were included in the with Uiso(H) = 1.2Ueq or 1.5Ueq (for methyl C). Final difference Fourier maps showed the highestand lowest electron densities of -0.182 and 0.157 e Å-3, respectively. Friedel pairs were averaged in the final refinement.Data collection: XSCANS (Bruker, 1997); cell
XSCANS (Bruker, 1997); data reduction: XSCANS (Bruker, 1997); 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).Fig. 1. ORTEP drawing of title compound with 35% probability ellipsoids, showing the atomic numbering scheme. | |
Fig. 2. A packing view along the a direction. |
C30H42N2O4 | F(000) = 1072 |
Mr = 494.66 | Dx = 1.220 Mg m−3 |
Orthorhombic, P212121 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2ac 2ab | Cell parameters from 52 reflections |
a = 8.5489 (11) Å | θ = 3.7–19.0° |
b = 10.9019 (18) Å | µ = 0.08 mm−1 |
c = 28.898 (3) Å | T = 295 K |
V = 2693.2 (6) Å3 | Prism, colorless |
Z = 4 | 0.5 × 0.4 × 0.3 mm |
Bruker P4 diffractometer | Rint = 0.031 |
Radiation source: fine-focus sealed tube | θmax = 25.5°, θmin = 2.0° |
Graphite monochromator | h = −1→10 |
ω scans | k = −13→1 |
3717 measured reflections | l = −1→35 |
2855 independent reflections | 3 standard reflections every 97 reflections |
2178 reflections with I > 2σ(I) | intensity decay: none |
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)] = 0.049 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.109 | H-atom parameters constrained |
S = 1.02 | w = 1/[σ2(Fo2) + (0.001P)2 + 1.3P] where P = (Fo2 + 2Fc2)/3 |
2855 reflections | (Δ/σ)max < 0.001 |
326 parameters | Δρmax = 0.16 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
C30H42N2O4 | V = 2693.2 (6) Å3 |
Mr = 494.66 | Z = 4 |
Orthorhombic, P212121 | Mo Kα radiation |
a = 8.5489 (11) Å | µ = 0.08 mm−1 |
b = 10.9019 (18) Å | T = 295 K |
c = 28.898 (3) Å | 0.5 × 0.4 × 0.3 mm |
Bruker P4 diffractometer | Rint = 0.031 |
3717 measured reflections | 3 standard reflections every 97 reflections |
2855 independent reflections | intensity decay: none |
2178 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.049 | 0 restraints |
wR(F2) = 0.109 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.16 e Å−3 |
2855 reflections | Δρmin = −0.18 e Å−3 |
326 parameters |
Experimental. absolute configuration has not been established by anomalous dispersion effects in diffraction measurements on the crystal. The enantiomer has been assigned by reference to unchanging chiral centres in the synthetic procedure. |
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 | ||
O1 | 0.6409 (6) | −0.3844 (3) | 0.25922 (12) | 0.0902 (11) | |
O2 | 0.4151 (4) | −0.0311 (2) | 0.41200 (9) | 0.0636 (9) | |
O3 | 0.0227 (4) | 0.4128 (3) | 0.47645 (11) | 0.0733 (9) | |
O4 | 0.0196 (5) | 0.6051 (3) | 0.50103 (11) | 0.0802 (10) | |
H4A | −0.0380 | 0.5758 | 0.5208 | 0.096* | |
N1 | 0.5282 (6) | −0.3188 (3) | 0.28470 (14) | 0.0767 (12) | |
N2 | 0.7751 (6) | −0.3138 (4) | 0.25298 (14) | 0.0826 (14) | |
C1 | 0.5253 (6) | −0.1096 (4) | 0.31919 (14) | 0.0592 (12) | |
H1A | 0.4552 | −0.1415 | 0.3427 | 0.071* | |
H1B | 0.4653 | −0.0574 | 0.2986 | 0.071* | |
C2 | 0.5954 (6) | −0.2133 (4) | 0.29242 (14) | 0.0587 (12) | |
C3 | 0.7457 (6) | −0.2096 (4) | 0.27309 (14) | 0.0621 (13) | |
C4 | 0.8579 (6) | −0.1039 (4) | 0.27610 (14) | 0.0586 (12) | |
C5 | 0.7758 (5) | 0.0033 (4) | 0.30352 (13) | 0.0535 (11) | |
H5A | 0.7143 | 0.0485 | 0.2805 | 0.064* | |
C6 | 0.8964 (5) | 0.0951 (4) | 0.32221 (14) | 0.0585 (11) | |
H6A | 0.9502 | 0.0594 | 0.3485 | 0.070* | |
H6B | 0.9734 | 0.1123 | 0.2985 | 0.070* | |
C7 | 0.8171 (5) | 0.2144 (4) | 0.33693 (14) | 0.0573 (11) | |
H7A | 0.7717 | 0.2530 | 0.3098 | 0.069* | |
H7B | 0.8959 | 0.2696 | 0.3492 | 0.069* | |
C8 | 0.6882 (5) | 0.1969 (4) | 0.37362 (13) | 0.0462 (10) | |
C9 | 0.5807 (5) | 0.0872 (3) | 0.36035 (13) | 0.0466 (10) | |
H9A | 0.5194 | 0.1173 | 0.3340 | 0.056* | |
C10 | 0.6578 (5) | −0.0339 (3) | 0.34242 (13) | 0.0483 (10) | |
C11 | 0.4616 (5) | 0.0705 (4) | 0.39885 (14) | 0.0526 (11) | |
C12 | 0.3977 (6) | 0.1813 (4) | 0.41969 (14) | 0.0535 (11) | |
H12A | 0.3130 | 0.1726 | 0.4396 | 0.064* | |
C13 | 0.4519 (5) | 0.2939 (3) | 0.41227 (13) | 0.0450 (10) | |
C14 | 0.5843 (5) | 0.3161 (3) | 0.37735 (13) | 0.0463 (10) | |
C15 | 0.6873 (5) | 0.4283 (4) | 0.39076 (15) | 0.0553 (11) | |
H15A | 0.7681 | 0.4011 | 0.4119 | 0.066* | |
H15B | 0.7386 | 0.4587 | 0.3631 | 0.066* | |
C16 | 0.5968 (5) | 0.5356 (3) | 0.41356 (14) | 0.0576 (11) | |
H16A | 0.6712 | 0.5968 | 0.4240 | 0.069* | |
H16B | 0.5302 | 0.5737 | 0.3905 | 0.069* | |
C17 | 0.4960 (5) | 0.4953 (4) | 0.45462 (14) | 0.0521 (10) | |
C18 | 0.3760 (5) | 0.4008 (3) | 0.43689 (13) | 0.0487 (10) | |
H18A | 0.3251 | 0.3666 | 0.4644 | 0.058* | |
C19 | 0.2459 (5) | 0.4588 (4) | 0.40792 (14) | 0.0541 (11) | |
H19A | 0.2902 | 0.4872 | 0.3789 | 0.065* | |
H19B | 0.1690 | 0.3963 | 0.4007 | 0.065* | |
C20 | 0.1633 (5) | 0.5660 (4) | 0.43147 (15) | 0.0554 (11) | |
C21 | 0.2844 (6) | 0.6604 (4) | 0.44773 (17) | 0.0653 (13) | |
H21A | 0.3316 | 0.6990 | 0.4209 | 0.078* | |
H21B | 0.2319 | 0.7237 | 0.4655 | 0.078* | |
C22 | 0.4116 (6) | 0.6038 (4) | 0.47708 (16) | 0.0644 (12) | |
H22A | 0.3659 | 0.5766 | 0.5060 | 0.077* | |
H22B | 0.4882 | 0.6666 | 0.4843 | 0.077* | |
C23 | 1.0152 (6) | −0.1466 (5) | 0.29607 (17) | 0.0815 (16) | |
H23A | 0.9998 | −0.1769 | 0.3269 | 0.122* | |
H23B | 1.0868 | −0.0788 | 0.2967 | 0.122* | |
H23C | 1.0573 | −0.2107 | 0.2770 | 0.122* | |
C24 | 0.8894 (7) | −0.0563 (4) | 0.22619 (13) | 0.0768 (15) | |
H24A | 0.7932 | −0.0282 | 0.2128 | 0.115* | |
H24B | 0.9316 | −0.1216 | 0.2077 | 0.115* | |
H24C | 0.9629 | 0.0102 | 0.2273 | 0.115* | |
C25 | 0.7345 (5) | −0.1141 (4) | 0.38010 (14) | 0.0589 (12) | |
H25A | 0.7778 | −0.1865 | 0.3662 | 0.088* | |
H25B | 0.6572 | −0.1373 | 0.4026 | 0.088* | |
H25C | 0.8162 | −0.0685 | 0.3950 | 0.088* | |
C26 | 0.7706 (5) | 0.1700 (4) | 0.42047 (13) | 0.0566 (11) | |
H26A | 0.8343 | 0.0980 | 0.4175 | 0.085* | |
H26B | 0.6932 | 0.1570 | 0.4440 | 0.085* | |
H26C | 0.8351 | 0.2386 | 0.4288 | 0.085* | |
C27 | 0.5036 (6) | 0.3478 (4) | 0.33047 (13) | 0.0582 (12) | |
H27A | 0.4405 | 0.4199 | 0.3342 | 0.087* | |
H27B | 0.4387 | 0.2804 | 0.3210 | 0.087* | |
H27C | 0.5820 | 0.3625 | 0.3073 | 0.087* | |
C28 | 0.5997 (6) | 0.4369 (4) | 0.49226 (14) | 0.0668 (12) | |
H28A | 0.5356 | 0.4117 | 0.5178 | 0.100* | |
H28B | 0.6753 | 0.4958 | 0.5027 | 0.100* | |
H28C | 0.6528 | 0.3668 | 0.4797 | 0.100* | |
C29 | 0.0481 (6) | 0.6278 (5) | 0.39767 (16) | 0.0791 (15) | |
H29A | −0.0275 | 0.5687 | 0.3873 | 0.119* | |
H29B | 0.1045 | 0.6592 | 0.3715 | 0.119* | |
H29C | −0.0046 | 0.6940 | 0.4131 | 0.119* | |
C30 | 0.0645 (5) | 0.5169 (4) | 0.47178 (15) | 0.0557 (11) |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.123 (3) | 0.0579 (19) | 0.090 (2) | 0.001 (3) | 0.019 (3) | −0.0219 (19) |
O2 | 0.081 (2) | 0.0426 (15) | 0.0673 (18) | −0.0104 (17) | 0.0202 (19) | 0.0001 (14) |
O3 | 0.084 (2) | 0.0523 (18) | 0.084 (2) | −0.007 (2) | 0.012 (2) | −0.0047 (16) |
O4 | 0.109 (3) | 0.0517 (17) | 0.080 (2) | 0.006 (2) | 0.023 (2) | −0.0056 (17) |
N1 | 0.102 (3) | 0.053 (2) | 0.075 (2) | 0.001 (3) | 0.008 (3) | −0.011 (2) |
N2 | 0.107 (4) | 0.061 (3) | 0.079 (3) | 0.012 (3) | 0.020 (3) | −0.013 (2) |
C1 | 0.069 (3) | 0.048 (2) | 0.061 (2) | 0.002 (3) | 0.000 (3) | −0.003 (2) |
C2 | 0.082 (3) | 0.044 (2) | 0.050 (2) | 0.001 (3) | −0.003 (3) | −0.003 (2) |
C3 | 0.086 (4) | 0.053 (3) | 0.047 (2) | 0.009 (3) | 0.005 (3) | −0.002 (2) |
C4 | 0.066 (3) | 0.058 (3) | 0.052 (2) | 0.010 (3) | 0.006 (2) | −0.002 (2) |
C5 | 0.059 (3) | 0.053 (2) | 0.048 (2) | 0.006 (2) | 0.004 (2) | 0.0004 (19) |
C6 | 0.054 (3) | 0.062 (3) | 0.059 (2) | −0.004 (3) | 0.009 (2) | 0.002 (2) |
C7 | 0.058 (3) | 0.054 (2) | 0.060 (3) | −0.007 (2) | 0.012 (2) | 0.000 (2) |
C8 | 0.048 (2) | 0.043 (2) | 0.047 (2) | −0.003 (2) | 0.003 (2) | 0.0021 (18) |
C9 | 0.052 (2) | 0.041 (2) | 0.048 (2) | −0.003 (2) | 0.000 (2) | 0.0028 (17) |
C10 | 0.053 (2) | 0.042 (2) | 0.049 (2) | 0.006 (2) | 0.003 (2) | 0.0019 (19) |
C11 | 0.057 (3) | 0.044 (2) | 0.056 (2) | −0.005 (2) | 0.006 (2) | −0.0002 (19) |
C12 | 0.059 (3) | 0.045 (2) | 0.057 (2) | −0.008 (2) | 0.013 (2) | 0.000 (2) |
C13 | 0.045 (2) | 0.045 (2) | 0.045 (2) | −0.002 (2) | 0.000 (2) | 0.0007 (18) |
C14 | 0.051 (2) | 0.040 (2) | 0.048 (2) | −0.003 (2) | −0.003 (2) | −0.0002 (18) |
C15 | 0.055 (3) | 0.049 (2) | 0.062 (3) | −0.013 (2) | 0.002 (2) | 0.002 (2) |
C16 | 0.060 (3) | 0.043 (2) | 0.070 (3) | −0.009 (2) | −0.004 (3) | −0.001 (2) |
C17 | 0.050 (2) | 0.048 (2) | 0.058 (2) | −0.007 (2) | −0.001 (2) | −0.007 (2) |
C18 | 0.051 (2) | 0.043 (2) | 0.053 (2) | 0.002 (2) | −0.003 (2) | −0.0029 (18) |
C19 | 0.054 (3) | 0.051 (2) | 0.058 (2) | 0.002 (2) | −0.004 (2) | 0.001 (2) |
C20 | 0.054 (3) | 0.048 (2) | 0.064 (3) | 0.007 (2) | −0.004 (2) | 0.002 (2) |
C21 | 0.065 (3) | 0.047 (2) | 0.084 (3) | −0.001 (2) | 0.003 (3) | −0.003 (2) |
C22 | 0.061 (3) | 0.050 (2) | 0.082 (3) | −0.002 (3) | −0.007 (3) | −0.016 (2) |
C23 | 0.079 (4) | 0.083 (4) | 0.082 (3) | 0.025 (3) | 0.007 (3) | −0.004 (3) |
C24 | 0.098 (4) | 0.080 (3) | 0.052 (2) | 0.002 (4) | 0.017 (3) | −0.008 (2) |
C25 | 0.075 (3) | 0.052 (2) | 0.050 (2) | 0.008 (3) | 0.000 (2) | 0.005 (2) |
C26 | 0.061 (3) | 0.058 (3) | 0.051 (2) | 0.005 (2) | −0.005 (2) | 0.003 (2) |
C27 | 0.071 (3) | 0.053 (2) | 0.051 (2) | 0.001 (3) | −0.003 (2) | 0.0071 (19) |
C28 | 0.066 (3) | 0.075 (3) | 0.059 (3) | 0.005 (3) | −0.009 (3) | −0.009 (2) |
C29 | 0.078 (4) | 0.078 (3) | 0.082 (3) | 0.016 (3) | −0.001 (3) | 0.024 (3) |
C30 | 0.053 (3) | 0.048 (2) | 0.066 (3) | 0.008 (2) | −0.012 (2) | −0.001 (2) |
O1—N2 | 1.393 (5) | C15—H15B | 0.9700 |
O1—N1 | 1.408 (5) | C16—C17 | 1.531 (5) |
O2—C11 | 1.237 (4) | C16—H16A | 0.9700 |
O3—C30 | 1.197 (5) | C16—H16B | 0.9700 |
O4—C30 | 1.336 (5) | C17—C22 | 1.530 (5) |
O4—H4A | 0.8200 | C17—C18 | 1.541 (5) |
N1—C2 | 1.304 (5) | C17—C28 | 1.541 (5) |
N2—C3 | 1.301 (5) | C18—C19 | 1.528 (5) |
C1—C2 | 1.495 (6) | C18—H18A | 0.9800 |
C1—C10 | 1.554 (6) | C19—C20 | 1.526 (5) |
C1—H1A | 0.9700 | C19—H19A | 0.9700 |
C1—H1B | 0.9700 | C19—H19B | 0.9700 |
C2—C3 | 1.401 (7) | C20—C21 | 1.534 (6) |
C3—C4 | 1.501 (6) | C20—C30 | 1.535 (6) |
C4—C23 | 1.535 (6) | C20—C29 | 1.542 (6) |
C4—C24 | 1.556 (5) | C21—C22 | 1.511 (6) |
C4—C5 | 1.578 (6) | C21—H21A | 0.9700 |
C5—C6 | 1.534 (6) | C21—H21B | 0.9700 |
C5—C10 | 1.564 (6) | C22—H22A | 0.9700 |
C5—H5A | 0.9800 | C22—H22B | 0.9700 |
C6—C7 | 1.527 (6) | C23—H23A | 0.9600 |
C6—H6A | 0.9700 | C23—H23B | 0.9600 |
C6—H6B | 0.9700 | C23—H23C | 0.9600 |
C7—C8 | 1.541 (5) | C24—H24A | 0.9600 |
C7—H7A | 0.9700 | C24—H24B | 0.9600 |
C7—H7B | 0.9700 | C24—H24C | 0.9600 |
C8—C9 | 1.556 (5) | C25—H25A | 0.9600 |
C8—C26 | 1.554 (5) | C25—H25B | 0.9600 |
C8—C14 | 1.578 (5) | C25—H25C | 0.9600 |
C9—C11 | 1.519 (5) | C26—H26A | 0.9600 |
C9—C10 | 1.565 (5) | C26—H26B | 0.9600 |
C9—H9A | 0.9800 | C26—H26C | 0.9600 |
C10—C25 | 1.543 (5) | C27—H27A | 0.9600 |
C11—C12 | 1.456 (5) | C27—H27B | 0.9600 |
C12—C13 | 1.330 (5) | C27—H27C | 0.9600 |
C12—H12A | 0.9300 | C28—H28A | 0.9600 |
C13—C18 | 1.512 (5) | C28—H28B | 0.9600 |
C13—C14 | 1.536 (5) | C28—H28C | 0.9600 |
C14—C15 | 1.556 (5) | C29—H29A | 0.9600 |
C14—C27 | 1.559 (5) | C29—H29B | 0.9600 |
C15—C16 | 1.549 (5) | C29—H29C | 0.9600 |
C15—H15A | 0.9700 | ||
N2—O1—N1 | 110.5 (3) | C15—C16—H16B | 108.9 |
C30—O4—H4A | 109.5 | H16A—C16—H16B | 107.8 |
C2—N1—O1 | 103.6 (4) | C22—C17—C16 | 111.8 (3) |
C3—N2—O1 | 105.4 (4) | C22—C17—C18 | 110.1 (3) |
C2—C1—C10 | 109.4 (4) | C16—C17—C18 | 108.0 (3) |
C2—C1—H1A | 109.8 | C22—C17—C28 | 106.9 (3) |
C10—C1—H1A | 109.8 | C16—C17—C28 | 110.0 (4) |
C2—C1—H1B | 109.8 | C18—C17—C28 | 110.0 (3) |
C10—C1—H1B | 109.8 | C13—C18—C19 | 111.9 (3) |
H1A—C1—H1B | 108.2 | C13—C18—C17 | 112.7 (3) |
N1—C2—C3 | 111.2 (4) | C19—C18—C17 | 113.0 (3) |
N1—C2—C1 | 125.3 (5) | C13—C18—H18A | 106.2 |
C3—C2—C1 | 123.5 (4) | C19—C18—H18A | 106.2 |
N2—C3—C2 | 109.2 (5) | C17—C18—H18A | 106.2 |
N2—C3—C4 | 124.9 (5) | C20—C19—C18 | 114.2 (3) |
C2—C3—C4 | 125.8 (4) | C20—C19—H19A | 108.7 |
C3—C4—C23 | 110.4 (4) | C18—C19—H19A | 108.7 |
C3—C4—C24 | 108.2 (4) | C20—C19—H19B | 108.7 |
C23—C4—C24 | 107.3 (4) | C18—C19—H19B | 108.7 |
C3—C4—C5 | 108.3 (4) | H19A—C19—H19B | 107.6 |
C23—C4—C5 | 115.2 (4) | C19—C20—C21 | 109.8 (4) |
C24—C4—C5 | 107.2 (3) | C19—C20—C30 | 109.0 (3) |
C6—C5—C10 | 110.5 (3) | C21—C20—C30 | 111.9 (4) |
C6—C5—C4 | 111.2 (4) | C19—C20—C29 | 110.4 (4) |
C10—C5—C4 | 117.1 (3) | C21—C20—C29 | 109.4 (4) |
C6—C5—H5A | 105.7 | C30—C20—C29 | 106.3 (4) |
C10—C5—H5A | 105.7 | C22—C21—C20 | 112.6 (3) |
C4—C5—H5A | 105.7 | C22—C21—H21A | 109.1 |
C7—C6—C5 | 110.8 (4) | C20—C21—H21A | 109.1 |
C7—C6—H6A | 109.5 | C22—C21—H21B | 109.1 |
C5—C6—H6A | 109.5 | C20—C21—H21B | 109.1 |
C7—C6—H6B | 109.5 | H21A—C21—H21B | 107.8 |
C5—C6—H6B | 109.5 | C21—C22—C17 | 114.6 (4) |
H6A—C6—H6B | 108.1 | C21—C22—H22A | 108.6 |
C6—C7—C8 | 113.8 (3) | C17—C22—H22A | 108.6 |
C6—C7—H7A | 108.8 | C21—C22—H22B | 108.6 |
C8—C7—H7A | 108.8 | C17—C22—H22B | 108.6 |
C6—C7—H7B | 108.8 | H22A—C22—H22B | 107.6 |
C8—C7—H7B | 108.8 | C4—C23—H23A | 109.5 |
H7A—C7—H7B | 107.7 | C4—C23—H23B | 109.5 |
C7—C8—C9 | 110.4 (3) | H23A—C23—H23B | 109.5 |
C7—C8—C26 | 107.4 (3) | C4—C23—H23C | 109.5 |
C9—C8—C26 | 109.8 (3) | H23A—C23—H23C | 109.5 |
C7—C8—C14 | 110.3 (3) | H23B—C23—H23C | 109.5 |
C9—C8—C14 | 108.5 (3) | C4—C24—H24A | 109.5 |
C26—C8—C14 | 110.5 (3) | C4—C24—H24B | 109.5 |
C11—C9—C8 | 107.9 (3) | H24A—C24—H24B | 109.5 |
C11—C9—C10 | 115.1 (3) | C4—C24—H24C | 109.5 |
C8—C9—C10 | 118.8 (3) | H24A—C24—H24C | 109.5 |
C11—C9—H9A | 104.5 | H24B—C24—H24C | 109.5 |
C8—C9—H9A | 104.5 | C10—C25—H25A | 109.5 |
C10—C9—H9A | 104.5 | C10—C25—H25B | 109.5 |
C25—C10—C1 | 108.3 (3) | H25A—C25—H25B | 109.5 |
C25—C10—C9 | 115.1 (3) | C10—C25—H25C | 109.5 |
C1—C10—C9 | 106.5 (3) | H25A—C25—H25C | 109.5 |
C25—C10—C5 | 112.3 (4) | H25B—C25—H25C | 109.5 |
C1—C10—C5 | 107.3 (3) | C8—C26—H26A | 109.5 |
C9—C10—C5 | 106.9 (3) | C8—C26—H26B | 109.5 |
O2—C11—C12 | 119.7 (4) | H26A—C26—H26B | 109.5 |
O2—C11—C9 | 123.2 (4) | C8—C26—H26C | 109.5 |
C12—C11—C9 | 117.0 (3) | H26A—C26—H26C | 109.5 |
C13—C12—C11 | 124.7 (4) | H26B—C26—H26C | 109.5 |
C13—C12—H12A | 117.7 | C14—C27—H27A | 109.5 |
C11—C12—H12A | 117.7 | C14—C27—H27B | 109.5 |
C12—C13—C18 | 119.1 (4) | H27A—C27—H27B | 109.5 |
C12—C13—C14 | 120.5 (4) | C14—C27—H27C | 109.5 |
C18—C13—C14 | 120.3 (3) | H27A—C27—H27C | 109.5 |
C13—C14—C15 | 112.1 (3) | H27B—C27—H27C | 109.5 |
C13—C14—C27 | 106.2 (3) | C17—C28—H28A | 109.5 |
C15—C14—C27 | 107.0 (3) | C17—C28—H28B | 109.5 |
C13—C14—C8 | 109.3 (3) | H28A—C28—H28B | 109.5 |
C15—C14—C8 | 110.3 (3) | C17—C28—H28C | 109.5 |
C27—C14—C8 | 111.9 (3) | H28A—C28—H28C | 109.5 |
C16—C15—C14 | 114.7 (3) | H28B—C28—H28C | 109.5 |
C16—C15—H15A | 108.6 | C20—C29—H29A | 109.5 |
C14—C15—H15A | 108.6 | C20—C29—H29B | 109.5 |
C16—C15—H15B | 108.6 | H29A—C29—H29B | 109.5 |
C14—C15—H15B | 108.6 | C20—C29—H29C | 109.5 |
H15A—C15—H15B | 107.6 | H29A—C29—H29C | 109.5 |
C17—C16—C15 | 113.2 (3) | H29B—C29—H29C | 109.5 |
C17—C16—H16A | 108.9 | O3—C30—O4 | 121.7 (4) |
C15—C16—H16A | 108.9 | O3—C30—C20 | 125.5 (4) |
C17—C16—H16B | 108.9 | O4—C30—C20 | 112.8 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H4A···O2i | 0.82 | 2.04 | 2.787 (4) | 151 |
C1—H1A···O2 | 0.97 | 2.36 | 2.969 (5) | 120 |
C25—H25B···O2 | 0.96 | 2.39 | 3.021 (5) | 123 |
Symmetry code: (i) x−1/2, −y+1/2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C30H42N2O4 |
Mr | 494.66 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 295 |
a, b, c (Å) | 8.5489 (11), 10.9019 (18), 28.898 (3) |
V (Å3) | 2693.2 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.5 × 0.4 × 0.3 |
Data collection | |
Diffractometer | Bruker P4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3717, 2855, 2178 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.606 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.049, 0.109, 1.02 |
No. of reflections | 2855 |
No. of parameters | 326 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.16, −0.18 |
Computer programs: XSCANS (Bruker, 1997), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O4—H4A···O2i | 0.82 | 2.04 | 2.787 (4) | 151.0 |
C1—H1A···O2 | 0.97 | 2.36 | 2.969 (5) | 120.0 |
C25—H25B···O2 | 0.96 | 2.39 | 3.021 (5) | 123.2 |
Symmetry code: (i) x−1/2, −y+1/2, −z+1. |
Acknowledgements
The authors acknowledge financial support from the NSFC (No. 20772071)
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.
Glycyrrhetinic acid is the aglycone of glycyrrhizin, a triterpenoid saponin found in the roots of licorice(glycyrrhiza glabra)(Yoshida et al., 2001). It is well known as a potent sweet saponin and a number of triterpenoids. Glycyrrhetinic acid and its derivatives have several pharmacological activities, such as anti-inflammatory(Finney et al., 1960), anti-viral(Yu et al., 2006) and anti-tumor(Su et al. 2004). Recently, our group has designed and synthesized a novel series of glycyrrhetinic acid derivatives by chemical modification, and [2,3-c][1,2,5]oxadiazol-glycyrrhetinic acid showed primarily considerable bioactivity of inhibiting growth of HepG-2 tumour cell.
The title compound was obtained as colourless plate in the orthorhombic space group P2(1)2(1)2(1). A view of the molecular structure with the numbering scheme is shown in Fig. 1 and selected dimensions are given in Table 1. The molecule is composed of five fused six-membered rings and a five-membered heterocyclic ring, viz. A(C1–C5/C10), B(C5–C10), C(C8/C9/C11–C14), D(C13–C18), E(C17–C22) and F(C2—N2—O2—N1—C3). Ring B, D and E adopt chair conformations, while ring A and C adopt a slightly distorted half-chair conformation as a result of the double bonds being in or out of rings. The lengths of single bonds N1–C2 and N2–C3 are nearly equal, though there is a gem-dimethyl on C4.