organic compounds
Secohellebrigeninamide
aGuangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, Jinan University, Guangzhou 510632, People's Republic of China
*Correspondence e-mail: trwjiang@jnu.edu.cn
The title compound, C26H37NO5, was the reaction product of hellebrigenin with N,N-dimethylformamide. It consists of three cyclohexane rings (A, B and C), one five-membered ring (D) and one dihydropyran ring (E). The stereochemistry of the ring junctions is is A/B cis, B/C trans, C/D cis and C/E trans. The cyclohexane rings A, B and C have chair conformations. Both the five-membered ring D and the dihydropyran ring adopt an Two orientations are found for the aldehyde group with occupancies of 0.608 (10) and 0.392 (10). In the crystal, short O—H⋯O hydrogen bonds and short C—H⋯O contacts involving the hydroxy group, terminal methyl group and carbonyl group link the molecules into a three-dimensional network.
Related literature
For previous isolation of hellebrigenin, see: Urscheler et al. (1955); Yang et al. (2010); Zhao et al. (2010). For the treatment of hellebrigenin with sodium hydroxide, see: Kupchan et al. (1969). For the stereochemistry of bufalin, see: Rohrer et al. (1982).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis PRO (Agilent, 2011); cell CrysAlis PRO; data reduction: XPREP in SHELXTL (Sheldrick, 2008); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: XP in SHELXTL; software used to prepare material for publication: SHELXTL.
Supporting information
10.1107/S160053681200520X/vm2153sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S160053681200520X/vm2153Isup2.hkl
Hellebrigenin (41.6 mg) was dissolved in DMF and refluxed for 3 h. After the reaction, the mixture was poured into water and extracted with ethyl acetate. The ethyl acetate extract was washed with water to remove the remaining DMF and condensed by a rotary evaporator under reduced pressure. The residue was recrystallized in methanol at room temperature to afford colorless crystals (32.5 mg) suitable for X-ray analysis.
The C-bound H atoms were positioned geometrically and were included in the
in the riding-model approximation, with C—H = 0.96 Å (CH3) and Uiso(H) = 1.5Ueq(C); 0.97 Å (CH2) and Uiso(H) = 1.2Ueq(C); 0.98 Å (CH) and Uiso(H) = 1.2Ueq(C); 0.93 Å (aryl H) and Uiso(H)= 1.2Ueq(C); O—H = 0.82 Å and Uiso(H) = 1.5Ueq(O). O3 and H19 are disordered over two positions with occupancies of 0.608 (10) and 0.392 (10). The coverage for the collection is low. It may be due to an inadequate collection strategy. Recollection of diffraction data was not thought to be necessary since the can be unambiguously assigned with reference to the known configuration of the closed related compound bufalin. The is indeterminate.Data collection: CrysAlis PRO (Agilent, 2011); cell
CrysAlis PRO (Agilent, 2011); data reduction: XPREP in SHELXTL (Sheldrick, 2008); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: XP in SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).C26H37NO5 | F(000) = 480 |
Mr = 443.57 | Dx = 1.264 Mg m−3 |
Monoclinic, P21 | Cu Kα radiation, λ = 1.54184 Å |
a = 6.6942 (1) Å | Cell parameters from 1847 reflections |
b = 16.0580 (4) Å | θ = 6.2–62.6° |
c = 10.9672 (3) Å | µ = 0.70 mm−1 |
β = 98.693 (2)° | T = 291 K |
V = 1165.38 (5) Å3 | Block, colorless |
Z = 2 | 0.38 × 0.30 × 0.25 mm |
Oxford Diffraction Gemini S Ultra Sapphire CCD diffractometer | 2534 independent reflections |
Radiation source: fine-focus sealed tube | 2431 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.021 |
ω scan | θmax = 62.7°, θmin = 5.5° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | h = −2→7 |
Tmin = 0.673, Tmax = 1.000 | k = −18→16 |
3575 measured reflections | l = −12→11 |
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)] = 0.046 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.130 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0899P)2 + 0.1076P] where P = (Fo2 + 2Fc2)/3 |
2534 reflections | (Δ/σ)max < 0.001 |
293 parameters | Δρmax = 0.18 e Å−3 |
1 restraint | Δρmin = −0.16 e Å−3 |
C26H37NO5 | V = 1165.38 (5) Å3 |
Mr = 443.57 | Z = 2 |
Monoclinic, P21 | Cu Kα radiation |
a = 6.6942 (1) Å | µ = 0.70 mm−1 |
b = 16.0580 (4) Å | T = 291 K |
c = 10.9672 (3) Å | 0.38 × 0.30 × 0.25 mm |
β = 98.693 (2)° |
Oxford Diffraction Gemini S Ultra Sapphire CCD diffractometer | 2534 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | 2431 reflections with I > 2σ(I) |
Tmin = 0.673, Tmax = 1.000 | Rint = 0.021 |
3575 measured reflections |
R[F2 > 2σ(F2)] = 0.046 | 1 restraint |
wR(F2) = 0.130 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.18 e Å−3 |
2534 reflections | Δρmin = −0.16 e Å−3 |
293 parameters |
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 | Occ. (<1) | |
O1 | 0.3441 (4) | 1.40909 (16) | 0.1536 (2) | 0.0750 (6) | |
H1A | 0.4127 | 1.4495 | 0.1793 | 0.113* | |
O2 | 0.0185 (3) | 1.30160 (16) | 0.1275 (2) | 0.0737 (7) | |
H2A | 0.0758 | 1.3465 | 0.1413 | 0.111* | |
O3 | −0.0767 (8) | 1.1408 (4) | 0.3299 (6) | 0.1087 (18) | 0.608 (10) |
O3A | −0.0065 (11) | 1.2140 (6) | 0.4159 (9) | 0.1087 (18) | 0.39 |
O4 | 0.2368 (3) | 0.91532 (13) | 0.12249 (17) | 0.0530 (5) | |
O5 | 0.5706 (4) | 0.54857 (15) | 0.2410 (3) | 0.0815 (7) | |
N1 | 0.9026 (4) | 0.56933 (19) | 0.3016 (3) | 0.0666 (7) | |
C1 | 0.3354 (5) | 1.2767 (2) | 0.3439 (3) | 0.0618 (8) | |
H1B | 0.2441 | 1.3234 | 0.3468 | 0.074* | |
H1C | 0.3765 | 1.2577 | 0.4279 | 0.074* | |
C2 | 0.5202 (5) | 1.3069 (3) | 0.2931 (3) | 0.0712 (9) | |
H2B | 0.5820 | 1.3521 | 0.3440 | 0.085* | |
H2C | 0.6177 | 1.2619 | 0.2968 | 0.085* | |
C3 | 0.4688 (5) | 1.3362 (2) | 0.1624 (3) | 0.0674 (9) | |
H3A | 0.5939 | 1.3489 | 0.1298 | 0.081* | |
C4 | 0.3537 (5) | 1.2682 (2) | 0.0838 (3) | 0.0634 (8) | |
H4A | 0.3137 | 1.2896 | 0.0010 | 0.076* | |
H4B | 0.4445 | 1.2217 | 0.0784 | 0.076* | |
C5 | 0.1669 (4) | 1.2363 (2) | 0.1317 (3) | 0.0560 (7) | |
C6 | 0.0671 (5) | 1.1673 (2) | 0.0493 (3) | 0.0671 (9) | |
H6A | −0.0642 | 1.1554 | 0.0724 | 0.080* | |
H6B | 0.0456 | 1.1868 | −0.0354 | 0.080* | |
C7 | 0.1889 (6) | 1.0873 (2) | 0.0561 (3) | 0.0644 (8) | |
H7A | 0.3133 | 1.0969 | 0.0231 | 0.077* | |
H7B | 0.1125 | 1.0450 | 0.0058 | 0.077* | |
C8 | 0.2392 (4) | 1.05563 (19) | 0.1893 (2) | 0.0473 (6) | |
H8A | 0.1111 | 1.0420 | 0.2177 | 0.057* | |
C9 | 0.3438 (4) | 1.12326 (18) | 0.2759 (2) | 0.0483 (6) | |
H9A | 0.4721 | 1.1361 | 0.2472 | 0.058* | |
C10 | 0.2204 (4) | 1.2060 (2) | 0.2691 (2) | 0.0515 (7) | |
C11 | 0.3965 (5) | 1.0893 (2) | 0.4077 (2) | 0.0599 (8) | |
H11A | 0.4701 | 1.1314 | 0.4598 | 0.072* | |
H11B | 0.2728 | 1.0772 | 0.4403 | 0.072* | |
C12 | 0.5241 (5) | 1.0104 (2) | 0.4113 (3) | 0.0613 (8) | |
H12A | 0.5511 | 0.9903 | 0.4955 | 0.074* | |
H12B | 0.6528 | 1.0240 | 0.3857 | 0.074* | |
C13 | 0.4233 (4) | 0.94111 (19) | 0.3285 (2) | 0.0497 (6) | |
C14 | 0.3650 (4) | 0.97681 (19) | 0.1972 (2) | 0.0445 (6) | |
C15 | 0.5674 (4) | 0.9822 (2) | 0.1456 (3) | 0.0545 (7) | |
H15A | 0.5486 | 0.9665 | 0.0592 | 0.065* | |
H15B | 0.6208 | 1.0384 | 0.1535 | 0.065* | |
C16 | 0.7123 (4) | 0.9212 (2) | 0.2229 (3) | 0.0598 (8) | |
H16A | 0.8179 | 0.9508 | 0.2760 | 0.072* | |
H16B | 0.7739 | 0.8835 | 0.1704 | 0.072* | |
C17 | 0.5736 (4) | 0.8739 (2) | 0.2993 (3) | 0.0520 (6) | |
H17A | 0.6491 | 0.8492 | 0.3741 | 0.062* | |
C18 | 0.2473 (5) | 0.9056 (3) | 0.3841 (3) | 0.0682 (9) | |
H18A | 0.1603 | 0.9501 | 0.4018 | 0.102* | |
H18B | 0.2976 | 0.8766 | 0.4590 | 0.102* | |
H18C | 0.1727 | 0.8677 | 0.3267 | 0.102* | |
C19 | 0.0265 (6) | 1.1947 (3) | 0.3181 (4) | 0.0756 (10) | |
H19A | −0.0214 | 1.2446 | 0.3458 | 0.091* | 0.608 (10) |
H19B | −0.0789 | 1.1699 | 0.2657 | 0.091* | 0.392 (10) |
C20 | 0.4571 (4) | 0.8096 (2) | 0.2173 (3) | 0.0509 (7) | |
C21 | 0.2995 (4) | 0.83593 (19) | 0.1362 (3) | 0.0533 (7) | |
H21A | 0.2281 | 0.7961 | 0.0855 | 0.064* | |
C22 | 0.5116 (4) | 0.7228 (2) | 0.2182 (3) | 0.0519 (7) | |
H22A | 0.4238 | 0.6878 | 0.1682 | 0.062* | |
C23 | 0.6737 (4) | 0.6871 (2) | 0.2826 (3) | 0.0533 (7) | |
H23A | 0.7655 | 0.7195 | 0.3343 | 0.064* | |
C24 | 0.7095 (5) | 0.5968 (2) | 0.2728 (3) | 0.0584 (7) | |
C25 | 0.9418 (7) | 0.4814 (3) | 0.2967 (6) | 0.1014 (15) | |
H25A | 0.8161 | 0.4518 | 0.2801 | 0.152* | |
H25B | 1.0148 | 0.4634 | 0.3744 | 0.152* | |
H25C | 1.0208 | 0.4703 | 0.2324 | 0.152* | |
C26 | 1.0793 (5) | 0.6229 (3) | 0.3278 (4) | 0.0850 (12) | |
H26A | 1.0369 | 0.6799 | 0.3291 | 0.127* | |
H26B | 1.1632 | 0.6156 | 0.2649 | 0.127* | |
H26C | 1.1543 | 0.6084 | 0.4065 | 0.127* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0879 (15) | 0.0492 (13) | 0.0877 (15) | −0.0031 (12) | 0.0124 (12) | −0.0062 (12) |
O2 | 0.0705 (12) | 0.0510 (13) | 0.0906 (16) | 0.0170 (12) | −0.0169 (11) | −0.0032 (13) |
O3 | 0.091 (3) | 0.098 (4) | 0.147 (4) | 0.003 (3) | 0.050 (3) | 0.008 (3) |
O3A | 0.091 (3) | 0.098 (4) | 0.147 (4) | 0.003 (3) | 0.050 (3) | 0.008 (3) |
O4 | 0.0530 (10) | 0.0431 (11) | 0.0563 (10) | −0.0014 (9) | −0.0130 (8) | −0.0010 (9) |
O5 | 0.0729 (14) | 0.0478 (14) | 0.122 (2) | −0.0068 (13) | 0.0100 (13) | −0.0097 (15) |
N1 | 0.0637 (15) | 0.0555 (16) | 0.0823 (17) | 0.0165 (13) | 0.0171 (12) | 0.0104 (14) |
C1 | 0.0785 (19) | 0.0551 (19) | 0.0496 (14) | 0.0123 (15) | 0.0023 (13) | −0.0106 (14) |
C2 | 0.0645 (17) | 0.062 (2) | 0.080 (2) | −0.0001 (17) | −0.0106 (15) | −0.0223 (19) |
C3 | 0.0655 (17) | 0.060 (2) | 0.079 (2) | −0.0063 (16) | 0.0204 (15) | −0.0040 (17) |
C4 | 0.085 (2) | 0.0552 (18) | 0.0507 (14) | 0.0045 (16) | 0.0126 (13) | −0.0032 (14) |
C5 | 0.0621 (15) | 0.0452 (16) | 0.0545 (15) | 0.0085 (14) | −0.0114 (12) | 0.0027 (14) |
C6 | 0.079 (2) | 0.0498 (19) | 0.0622 (17) | 0.0052 (17) | −0.0229 (15) | 0.0032 (16) |
C7 | 0.088 (2) | 0.0491 (18) | 0.0469 (14) | 0.0056 (16) | −0.0193 (13) | −0.0018 (14) |
C8 | 0.0463 (12) | 0.0452 (15) | 0.0460 (13) | 0.0063 (12) | −0.0065 (10) | 0.0009 (12) |
C9 | 0.0524 (13) | 0.0479 (16) | 0.0415 (13) | 0.0067 (12) | −0.0027 (10) | −0.0028 (12) |
C10 | 0.0534 (14) | 0.0478 (16) | 0.0516 (14) | 0.0081 (13) | 0.0027 (11) | 0.0007 (13) |
C11 | 0.0778 (18) | 0.0543 (18) | 0.0423 (13) | 0.0158 (16) | −0.0083 (12) | −0.0046 (13) |
C12 | 0.0705 (17) | 0.0562 (19) | 0.0494 (14) | 0.0096 (16) | −0.0157 (13) | −0.0019 (14) |
C13 | 0.0492 (13) | 0.0487 (16) | 0.0463 (13) | 0.0076 (13) | −0.0091 (10) | 0.0006 (12) |
C14 | 0.0426 (12) | 0.0424 (14) | 0.0451 (13) | −0.0002 (12) | −0.0041 (10) | −0.0032 (11) |
C15 | 0.0557 (14) | 0.0477 (16) | 0.0611 (15) | −0.0030 (14) | 0.0123 (12) | −0.0072 (14) |
C16 | 0.0442 (13) | 0.0497 (18) | 0.0839 (19) | −0.0017 (13) | 0.0047 (12) | −0.0115 (16) |
C17 | 0.0474 (12) | 0.0474 (15) | 0.0558 (14) | 0.0046 (13) | −0.0097 (11) | −0.0012 (14) |
C18 | 0.0688 (17) | 0.076 (2) | 0.0592 (16) | 0.0125 (18) | 0.0086 (13) | 0.0127 (16) |
C19 | 0.067 (2) | 0.067 (2) | 0.099 (3) | 0.0136 (19) | 0.0331 (19) | 0.006 (2) |
C20 | 0.0450 (12) | 0.0463 (16) | 0.0586 (16) | 0.0016 (12) | −0.0012 (11) | 0.0023 (13) |
C21 | 0.0546 (14) | 0.0414 (15) | 0.0601 (16) | −0.0046 (13) | −0.0038 (12) | −0.0011 (13) |
C22 | 0.0543 (14) | 0.0408 (15) | 0.0597 (14) | −0.0028 (13) | 0.0054 (11) | −0.0013 (13) |
C23 | 0.0528 (14) | 0.0448 (17) | 0.0614 (16) | 0.0028 (13) | 0.0059 (12) | −0.0001 (13) |
C24 | 0.0641 (16) | 0.0458 (17) | 0.0671 (17) | 0.0049 (15) | 0.0159 (13) | 0.0026 (14) |
C25 | 0.097 (3) | 0.056 (2) | 0.158 (4) | 0.024 (2) | 0.041 (3) | 0.012 (3) |
C26 | 0.0605 (19) | 0.081 (3) | 0.112 (3) | 0.0096 (19) | 0.0097 (17) | 0.012 (2) |
O1—C3 | 1.432 (4) | C10—C19 | 1.489 (5) |
O1—H1A | 0.8200 | C11—C12 | 1.525 (4) |
O2—C5 | 1.440 (4) | C11—H11A | 0.9700 |
O2—H2A | 0.8200 | C11—H11B | 0.9700 |
O3—C19 | 1.127 (7) | C12—C13 | 1.528 (4) |
O3A—C19 | 1.169 (10) | C12—H12A | 0.9700 |
O4—C21 | 1.343 (4) | C12—H12B | 0.9700 |
O4—C14 | 1.473 (3) | C13—C18 | 1.517 (5) |
O5—C24 | 1.219 (4) | C13—C17 | 1.543 (4) |
N1—C24 | 1.357 (4) | C13—C14 | 1.544 (4) |
N1—C25 | 1.439 (5) | C14—C15 | 1.548 (4) |
N1—C26 | 1.455 (5) | C15—C16 | 1.540 (5) |
C1—C2 | 1.511 (5) | C15—H15A | 0.9700 |
C1—C10 | 1.538 (5) | C15—H15B | 0.9700 |
C1—H1B | 0.9700 | C16—C17 | 1.541 (5) |
C1—H1C | 0.9700 | C16—H16A | 0.9700 |
C2—C3 | 1.500 (5) | C16—H16B | 0.9700 |
C2—H2B | 0.9700 | C17—C20 | 1.506 (4) |
C2—H2C | 0.9700 | C17—H17A | 0.9800 |
C3—C4 | 1.526 (5) | C18—H18A | 0.9600 |
C3—H3A | 0.9800 | C18—H18B | 0.9600 |
C4—C5 | 1.517 (5) | C18—H18C | 0.9600 |
C4—H4A | 0.9700 | C19—H19A | 0.9300 |
C4—H4B | 0.9700 | C19—H19B | 0.9300 |
C5—C6 | 1.519 (4) | C20—C21 | 1.342 (4) |
C5—C10 | 1.572 (4) | C20—C22 | 1.441 (4) |
C6—C7 | 1.518 (5) | C21—H21A | 0.9300 |
C6—H6A | 0.9700 | C22—C23 | 1.331 (4) |
C6—H6B | 0.9700 | C22—H22A | 0.9300 |
C7—C8 | 1.534 (4) | C23—C24 | 1.477 (4) |
C7—H7A | 0.9700 | C23—H23A | 0.9300 |
C7—H7B | 0.9700 | C25—H25A | 0.9600 |
C8—C14 | 1.515 (4) | C25—H25B | 0.9600 |
C8—C9 | 1.540 (4) | C25—H25C | 0.9600 |
C8—H8A | 0.9800 | C26—H26A | 0.9600 |
C9—C11 | 1.535 (4) | C26—H26B | 0.9600 |
C9—C10 | 1.560 (4) | C26—H26C | 0.9600 |
C9—H9A | 0.9800 | ||
C3—O1—H1A | 109.5 | C13—C12—H12B | 108.9 |
C5—O2—H2A | 109.5 | H12A—C12—H12B | 107.7 |
C21—O4—C14 | 115.3 (2) | C18—C13—C12 | 109.6 (3) |
C24—N1—C25 | 118.9 (3) | C18—C13—C17 | 113.0 (3) |
C24—N1—C26 | 124.9 (3) | C12—C13—C17 | 113.0 (2) |
C25—N1—C26 | 116.1 (3) | C18—C13—C14 | 114.3 (2) |
C2—C1—C10 | 114.3 (3) | C12—C13—C14 | 108.1 (2) |
C2—C1—H1B | 108.7 | C17—C13—C14 | 98.5 (2) |
C10—C1—H1B | 108.7 | O4—C14—C8 | 104.82 (18) |
C2—C1—H1C | 108.7 | O4—C14—C13 | 108.3 (2) |
C10—C1—H1C | 108.7 | C8—C14—C13 | 115.1 (2) |
H1B—C1—H1C | 107.6 | O4—C14—C15 | 107.6 (2) |
C3—C2—C1 | 111.8 (3) | C8—C14—C15 | 116.2 (3) |
C3—C2—H2B | 109.3 | C13—C14—C15 | 104.5 (2) |
C1—C2—H2B | 109.3 | C16—C15—C14 | 106.0 (2) |
C3—C2—H2C | 109.3 | C16—C15—H15A | 110.5 |
C1—C2—H2C | 109.3 | C14—C15—H15A | 110.5 |
H2B—C2—H2C | 107.9 | C16—C15—H15B | 110.5 |
O1—C3—C2 | 111.6 (3) | C14—C15—H15B | 110.5 |
O1—C3—C4 | 107.9 (3) | H15A—C15—H15B | 108.7 |
C2—C3—C4 | 109.7 (3) | C15—C16—C17 | 103.4 (2) |
O1—C3—H3A | 109.2 | C15—C16—H16A | 111.1 |
C2—C3—H3A | 109.2 | C17—C16—H16A | 111.1 |
C4—C3—H3A | 109.2 | C15—C16—H16B | 111.1 |
C5—C4—C3 | 114.7 (3) | C17—C16—H16B | 111.1 |
C5—C4—H4A | 108.6 | H16A—C16—H16B | 109.0 |
C3—C4—H4A | 108.6 | C20—C17—C16 | 108.3 (2) |
C5—C4—H4B | 108.6 | C20—C17—C13 | 107.9 (2) |
C3—C4—H4B | 108.6 | C16—C17—C13 | 103.5 (3) |
H4A—C4—H4B | 107.6 | C20—C17—H17A | 112.2 |
O2—C5—C4 | 110.1 (3) | C16—C17—H17A | 112.2 |
O2—C5—C6 | 105.8 (2) | C13—C17—H17A | 112.2 |
C4—C5—C6 | 110.6 (3) | C13—C18—H18A | 109.5 |
O2—C5—C10 | 108.2 (2) | C13—C18—H18B | 109.5 |
C4—C5—C10 | 110.8 (2) | H18A—C18—H18B | 109.5 |
C6—C5—C10 | 111.2 (3) | C13—C18—H18C | 109.5 |
C7—C6—C5 | 113.8 (2) | H18A—C18—H18C | 109.5 |
C7—C6—H6A | 108.8 | H18B—C18—H18C | 109.5 |
C5—C6—H6A | 108.8 | O3—C19—O3A | 83.9 (6) |
C7—C6—H6B | 108.8 | O3—C19—C10 | 135.9 (5) |
C5—C6—H6B | 108.8 | O3A—C19—C10 | 126.5 (6) |
H6A—C6—H6B | 107.7 | O3—C19—H19A | 112.1 |
C6—C7—C8 | 111.5 (3) | O3A—C19—H19A | 49.4 |
C6—C7—H7A | 109.3 | C10—C19—H19A | 112.1 |
C8—C7—H7A | 109.3 | O3—C19—H19B | 47.2 |
C6—C7—H7B | 109.3 | O3A—C19—H19B | 116.8 |
C8—C7—H7B | 109.3 | C10—C19—H19B | 116.8 |
H7A—C7—H7B | 108.0 | H19A—C19—H19B | 107.7 |
C14—C8—C7 | 111.8 (2) | C21—C20—C22 | 118.8 (3) |
C14—C8—C9 | 110.88 (19) | C21—C20—C17 | 117.7 (3) |
C7—C8—C9 | 111.6 (2) | C22—C20—C17 | 123.4 (2) |
C14—C8—H8A | 107.4 | C20—C21—O4 | 125.0 (3) |
C7—C8—H8A | 107.4 | C20—C21—H21A | 117.5 |
C9—C8—H8A | 107.4 | O4—C21—H21A | 117.5 |
C11—C9—C8 | 110.4 (2) | C23—C22—C20 | 127.3 (3) |
C11—C9—C10 | 113.1 (2) | C23—C22—H22A | 116.4 |
C8—C9—C10 | 112.5 (2) | C20—C22—H22A | 116.4 |
C11—C9—H9A | 106.8 | C22—C23—C24 | 120.8 (3) |
C8—C9—H9A | 106.8 | C22—C23—H23A | 119.6 |
C10—C9—H9A | 106.8 | C24—C23—H23A | 119.6 |
C19—C10—C1 | 106.9 (3) | O5—C24—N1 | 121.3 (3) |
C19—C10—C9 | 111.3 (3) | O5—C24—C23 | 121.3 (3) |
C1—C10—C9 | 112.6 (2) | N1—C24—C23 | 117.5 (3) |
C19—C10—C5 | 107.4 (2) | N1—C25—H25A | 109.5 |
C1—C10—C5 | 107.8 (3) | N1—C25—H25B | 109.5 |
C9—C10—C5 | 110.6 (2) | H25A—C25—H25B | 109.5 |
C12—C11—C9 | 111.5 (2) | N1—C25—H25C | 109.5 |
C12—C11—H11A | 109.3 | H25A—C25—H25C | 109.5 |
C9—C11—H11A | 109.3 | H25B—C25—H25C | 109.5 |
C12—C11—H11B | 109.3 | N1—C26—H26A | 109.5 |
C9—C11—H11B | 109.3 | N1—C26—H26B | 109.5 |
H11A—C11—H11B | 108.0 | H26A—C26—H26B | 109.5 |
C11—C12—C13 | 113.2 (2) | N1—C26—H26C | 109.5 |
C11—C12—H12A | 108.9 | H26A—C26—H26C | 109.5 |
C13—C12—H12A | 108.9 | H26B—C26—H26C | 109.5 |
C11—C12—H12B | 108.9 | ||
C10—C1—C2—C3 | 57.5 (4) | C7—C8—C14—C13 | 179.7 (2) |
C1—C2—C3—O1 | 65.9 (4) | C9—C8—C14—C13 | 54.5 (3) |
C1—C2—C3—C4 | −53.7 (4) | C7—C8—C14—C15 | 57.1 (3) |
O1—C3—C4—C5 | −67.4 (4) | C9—C8—C14—C15 | −68.1 (3) |
C2—C3—C4—C5 | 54.5 (4) | C18—C13—C14—O4 | −47.9 (3) |
C3—C4—C5—O2 | 65.0 (3) | C12—C13—C14—O4 | −170.2 (2) |
C3—C4—C5—C6 | −178.4 (3) | C17—C13—C14—O4 | 72.2 (2) |
C3—C4—C5—C10 | −54.7 (4) | C18—C13—C14—C8 | 69.0 (4) |
O2—C5—C6—C7 | −171.6 (3) | C12—C13—C14—C8 | −53.3 (3) |
C4—C5—C6—C7 | 69.2 (4) | C17—C13—C14—C8 | −170.9 (2) |
C10—C5—C6—C7 | −54.3 (4) | C18—C13—C14—C15 | −162.4 (3) |
C5—C6—C7—C8 | 55.2 (4) | C12—C13—C14—C15 | 75.3 (3) |
C6—C7—C8—C14 | −178.7 (3) | C17—C13—C14—C15 | −42.3 (3) |
C6—C7—C8—C9 | −53.8 (3) | O4—C14—C15—C16 | −93.9 (3) |
C14—C8—C9—C11 | −53.4 (3) | C8—C14—C15—C16 | 149.1 (2) |
C7—C8—C9—C11 | −178.7 (3) | C13—C14—C15—C16 | 21.1 (3) |
C14—C8—C9—C10 | 179.2 (2) | C14—C15—C16—C17 | 9.2 (3) |
C7—C8—C9—C10 | 53.9 (3) | C15—C16—C17—C20 | 78.0 (3) |
C2—C1—C10—C19 | −170.2 (3) | C15—C16—C17—C13 | −36.4 (3) |
C2—C1—C10—C9 | 67.3 (4) | C18—C13—C17—C20 | 55.1 (3) |
C2—C1—C10—C5 | −55.0 (3) | C12—C13—C17—C20 | −179.8 (2) |
C11—C9—C10—C19 | −59.4 (3) | C14—C13—C17—C20 | −66.0 (3) |
C8—C9—C10—C19 | 66.6 (3) | C18—C13—C17—C16 | 169.7 (2) |
C11—C9—C10—C1 | 60.6 (3) | C12—C13—C17—C16 | −65.2 (3) |
C8—C9—C10—C1 | −173.4 (2) | C14—C13—C17—C16 | 48.6 (3) |
C11—C9—C10—C5 | −178.6 (2) | C1—C10—C19—O3 | −147.7 (7) |
C8—C9—C10—C5 | −52.7 (3) | C9—C10—C19—O3 | −24.3 (8) |
O2—C5—C10—C19 | 46.2 (3) | C5—C10—C19—O3 | 96.8 (7) |
C4—C5—C10—C19 | 167.0 (3) | C1—C10—C19—O3A | −22.8 (8) |
C6—C5—C10—C19 | −69.6 (4) | C9—C10—C19—O3A | 100.6 (7) |
O2—C5—C10—C1 | −68.6 (3) | C5—C10—C19—O3A | −138.3 (7) |
C4—C5—C10—C1 | 52.2 (3) | C16—C17—C20—C21 | −77.4 (3) |
C6—C5—C10—C1 | 175.6 (2) | C13—C17—C20—C21 | 34.0 (4) |
O2—C5—C10—C9 | 167.8 (2) | C16—C17—C20—C22 | 99.9 (3) |
C4—C5—C10—C9 | −71.4 (3) | C13—C17—C20—C22 | −148.8 (3) |
C6—C5—C10—C9 | 52.0 (3) | C22—C20—C21—O4 | −177.6 (3) |
C8—C9—C11—C12 | 55.2 (3) | C17—C20—C21—O4 | −0.2 (5) |
C10—C9—C11—C12 | −177.7 (3) | C14—O4—C21—C20 | 5.0 (4) |
C9—C11—C12—C13 | −57.2 (4) | C21—C20—C22—C23 | 172.7 (3) |
C11—C12—C13—C18 | −71.4 (3) | C17—C20—C22—C23 | −4.5 (5) |
C11—C12—C13—C17 | 161.6 (3) | C20—C22—C23—C24 | −179.5 (3) |
C11—C12—C13—C14 | 53.8 (3) | C25—N1—C24—O5 | −1.4 (5) |
C21—O4—C14—C8 | −166.9 (2) | C26—N1—C24—O5 | 173.2 (4) |
C21—O4—C14—C13 | −43.6 (3) | C25—N1—C24—C23 | 178.1 (4) |
C21—O4—C14—C15 | 68.8 (3) | C26—N1—C24—C23 | −7.3 (5) |
C7—C8—C14—O4 | −61.5 (3) | C22—C23—C24—O5 | −24.2 (5) |
C9—C8—C14—O4 | 173.3 (2) | C22—C23—C24—N1 | 156.4 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1A···O5i | 0.82 | 1.97 | 2.790 (3) | 178 |
C25—H25C···O1ii | 0.96 | 2.64 | 3.513 (3) | 152 |
Symmetry codes: (i) x, y+1, z; (ii) x+1, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | C26H37NO5 |
Mr | 443.57 |
Crystal system, space group | Monoclinic, P21 |
Temperature (K) | 291 |
a, b, c (Å) | 6.6942 (1), 16.0580 (4), 10.9672 (3) |
β (°) | 98.693 (2) |
V (Å3) | 1165.38 (5) |
Z | 2 |
Radiation type | Cu Kα |
µ (mm−1) | 0.70 |
Crystal size (mm) | 0.38 × 0.30 × 0.25 |
Data collection | |
Diffractometer | Oxford Diffraction Gemini S Ultra Sapphire CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2004) |
Tmin, Tmax | 0.673, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3575, 2534, 2431 |
Rint | 0.021 |
(sin θ/λ)max (Å−1) | 0.576 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.130, 1.04 |
No. of reflections | 2534 |
No. of parameters | 293 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.18, −0.16 |
Absolute structure parameter | −0.3 (3) |
Computer programs: CrysAlis PRO (Agilent, 2011), XPREP in SHELXTL (Sheldrick, 2008), XP in SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1A···O5i | 0.820 | 1.970 | 2.790 (3) | 178.4 |
C25—H25C···O1ii | 0.96 | 2.64 | 3.513 (3) | 152 |
Symmetry codes: (i) x, y+1, z; (ii) x+1, y−1, z. |
Acknowledgements
This work was supported by grants from the New Century Excellent Talents Scheme of the Ministry of Education (grant No. NCET-08–0612), Guangdong High Level Talent Scheme and the Fundamental Research Funds for the Central Universities (grant No. 21609202).
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.
Hellebrigenin is a cardiac steroid. It was firstly isolated from the European toad in 1955 (Urscheler et al., 1955). Since then, it was isolated from the rhizomes of Helleborus thibetanus (Yang et al., 2010) and the skin of the Chinese toad Bufo bufo gargarizans (Zhao et al., 2010). The lactone ring at C-17 is not stable in alkaline conditions. Treatment of hellebrigenin with sodium hydroxide in methanol affords methyl isohellebrigeninate (Kupchan et al., 1969). Recently we treated hellebrigenin with N,N-dimethylformamide (DMF), and a new derivative named secohellebrigeninamide was obtained. We report herein the crystal structure of this compound.
The colorless blocks of crystals were obtained by recrystallization from the methanol solution at room temperature. The molecule (Fig. 1) is composed of three cyclohexane rings (A, B and C), one five-membered ring (D) and one dihydropyran ring (E). The stereochemistry of the ring juncture is A/B cis, B/C trans, C/D cis and C/E trans.
The cyclohexane rings A, B and C have normal chair conformations. The five-membered ring D adopts an envelope conformation with C13 displaced by 0.7246 (2) Å from the mean plane of the remaining four atoms (C14, C15, C16 and C17). Similarly, the dihydropyran ring E also adopts an envelope conformation with C13 displaced by 0.8848 (3) Å from the mean plane of the remaining five atoms (C14, C17, C20, C21 and O4). The absolute configuration determined for bufalin (Rohrer et al., 1982), a similar cardiac steroid, was invoked, giving the assignments of the chiral centres in the molecule as shown in Fig. 1.
A short intermolecular O—H···O hydrogen bond (Table 1) between the hydroxyl group at C3 and the carbonyl group at C24 [O1—H1A···O5i, 2.790 (4) Å; symmetry code: (i) x,y + 1, z] links adjacent molecules into chains along the b-axis. Adjacent chains are linked by short C—H···O contacts between the terminal methyl group and the hydroxyl group at C3 [C25—H25C···O1ii, 3.513 (3) Å; symmetry code: (ii) x + 1, y - 1, z] into a three-dimensional network (Fig. 2).