MD Marine Drugs MD 1660-3397 Molecular Diversity Preservation International 10.3390/md9101829 marinedrugs-09-01829 Article Polyhydroxylated Steroids from the Bamboo Coral Isis hippuris ChenWei-Hua1 WangShang-Kwei2* DuhChang-Yih13* Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan; E-Mail: x_x1224@yahoo.com.tw Department of Microbiology, Kaohsiung Medical University, Kaohsiung 807, Taiwan Centers for Asia-Pacific Ocean Research and Translational Biopharmaceuticals, National Sun Yat-sen University, Kaohsiung 804, Taiwan Authors to whom correspondence should be addressed; E-Mails: yihduh@mail.nsysu.edu.tw (C.-Y.D.); skwang@cc.kmu.edu.tw (S.-K.W.); Tel.: +886-7-525-2000 (ext. 5036) (C.-Y.D.); +886-7-312-1101 (ext. 2150) (S.-K.W.); Fax: +886-7-525-5020 (C.-Y.D.). 2011 10 10 2011 9 10 1829 1839 25 8 2011 24 9 2011 30 9 2011 © 2011 by the authors; licensee MDPI, Basel, Switzerland 2011

This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).

In previous studies on the secondary metabolites of the Taiwanese octocoral Isis hippuris, specimens have always been collected at Green Island. In the course of our studies on bioactive compounds from marine organisms, the acetone-solubles of the Taiwanese octocoral I. hippuris collected at Orchid Island have led to the isolation of five new polyoxygenated steroids: hipposterone M–O (1–3), hipposterol G (4) and hippuristeroketal A (5). The structures of these compounds were determined on the basis of their spectroscopic and physical data. The anti-HCMV (human cytomegalovirus) activity of 1–5 and their cytotoxicity against selected cell lines were evaluated. Compound 2 exhibited inhibitory activity against HCMV, with an EC50 value of 6.0 μg/mL.

 octocoral Isis hippuris anti-HCMV activity 1. Introduction

The octocoral Isis hippuris, distributed widely in the western Pacific, has yielded a number of polyoxygenated steroids, including hippuristanol type [1–9], gorgosterol type [10–14], hippuristerone type [3,14,15], and hippuristerol type [3,14–16]. Those of the first type were originally reported as cytotoxins and later rediscovered as selective inhibitors against the translation factor eIF4A [17,18]. Some of the second types were reported to show cytotoxicity or a reversal of multidrug resistance activity [10]. The samples for previous studies on the secondary metabolites of Taiwanese octocoral I. hippuris were all collected at Green Island [5–7,12,14,15]. In our continued study of the bioactive metabolites from marine organism, the Taiwanese octocoral I. hippuris (Figure 1) collected at Orchid Island was selected for study since its acetone extract exhibited antiviral activity against HCMV. Bioactivity-guided fractionation resulted in the isolation of five polyoxygenated steroids: hipposterone M–O (1–3), hipposterol G (4), hippuristeroketal A (5) (Figure 2). We describe herein the isolation, structure elucidation, and biological activity of these compounds.

 2. Results and Discussion

The molecular formula C33H52O8 was assigned to hipposterone M (1) on the basis of positive HRESIMS (found m/z 599.3556 [M + Na]+), implying eight degrees of unsaturation. Its IR spectrum revealed the absorptions for hydroxyl (νmax 3454 cm−1), ketone carbonyl (νmax 1717 cm−1), and ester carbonyl (νmax 1733 cm−1) groups. NMR data (Tables 1 and 2) of 1 indicated the presence of a ketone (δC 211.7), two ester cabonyls, two oxygenated sp3 methines, an oxygenated sp3 methylene, three oxygenated sp3 quaternary carbons, two secondary methyls, four tertiary methyls, six non-oxygenated sp3 methines, eight non-oxygenated sp3 methylenes, and two non-oxygenated sp3 quaternary carbons. NMR signals (Table 1) at δC 80.0 (qC) and 67.1 (qC) suggested the existence of a tetrasubstituted expoxy. The quaternary carbon at δC 85.5, which has HMBC correlation (Figure 3) with tertiary methyl signals at δH 1.56 (s) and 1.43 (s) (Table 2) disclosed the presence of –OC(CH3)2. By extensive analysis of 2D NMR spectra, including COSY, HSQC, NOESY (Figure 4) and HMBC, 1 was shown to be a derivative of hippuristerone A [15]. HMBC correlations (Figure 3) from H2-18 (δH 3.94 and 3.75) to C-12, C-13, C-14, and C-17 established 1 as 18-hydroxyhippuristerone A. The stereochemistry of the side chain moiety was determined by comparison of the 1H and 13C NMR spectral data with those of hippuristerone A.

Hipposterone N (2) had a molecular formula of C31H50O7, as suggested by the NMR and HRESIMS data. Its IR spectrum also showed the absorptions for hydroxyl (νmax 3454 cm−1), ketone carbonyl (νmax 1715 cm−1), and ester carbonyl (νmax 1731 cm−1) groups. NMR data (Tables 1 and 2) of 2 revealed the presence of a ketone (δC 211.7), an ester cabonyl, two oxygenated sp3 methines, an oxygenated sp3 methylene, three oxygenated sp3 quaternary carbons, two secondary methyls, four tertiary methyls, six non-oxygenated sp3 methines, eight non-oxygenated sp3 methylenes, and two non-oxygenated sp3 quaternary carbons. NMR data (Tables 1 and 2) (Figure 3) of 2 resembled those of 1 except for a hydroxyl group replacing the tertiary acetoxyl in 1 [14]. HMBC correlations (Figure 3) from H3-26 (δH 1.24) and H3-27 (δH 1.21) to C-25 established 2 as a 25-deacetyl-18-hydroxy derivative of hippuristerone A. The stereochemistry of the side chain moiety was determined by comparison of the 1H and 13C NMR data with those of hippuristerones F, H, and I isolated from I. hippuris [16].

The positive HRESIMS of hipposterone O (3) established a molecular formula of C35H54O10. NMR data (Tables 1 and 2) of 3 showed the presence of a ketone (δC 211.5), three ester cabonyls, two oxygenated sp3 methines, two oxygenated sp3 methylene, three oxygenated sp3 quaternary carbons, two secondary methyls, three tertiary methyls, six non-oxygenated sp3 methines, eight non-oxygenated sp3 methylenes, and two non-oxygenated sp3 quaternary carbons. By comparison of NMR spectroscopic data (Tables 1 and 2) of 3 with those of hippuristerone J [14], the primary acetoxy group at C-21 was shift to C-18 on the basis of HMBC correlations (Figure 3) from H2-18 [δH 4.23 (1H, d, J = 11.6 Hz) and 4.30 (1H, d, J = 11.6 Hz)] to C-12, C-13, C-14, C-17, and carbonyl carbon of 18-OAc. The stereochemistry of the side chain moiety was determined by comparison of the 1H and 13C NMR spectral data with those of hippuristerones J and K previously isolated from I. hippuris [14].

Hipposterol G (4) was isolated as a white powder, and its molecular formula, C35H56O9, was determined by HRESIMS. Its IR spectrum revealed the functionalities of hydroxyl (νmax 3471 cm−1) and ester carbonyl (νmax 1734 cm−1). NMR data (Tables 1 and 2) of 4 indicated the presence of three ester cabonyls, three oxygenated sp3 methines, an oxygenated sp3 methylene, three oxygenated sp3 quaternary carbons, two secondary methyls, four tertiary methyls, six non-oxygenated sp3 methines, eight non-oxygenated sp3 methylenes, and two non-oxygenated sp3 quaternary carbons. NMR data (Tables 1 and 2) of 4 were similar to those of hippuristerone G [16] with the absence of the ketone carbon signal at δC 211.6 ppm and the presence of signal at δH 3.60 ppm NOE correlation H-3/H-5 and chemical shift values for C-1–C-7 nuclei. This is in agreement with the results reported for 5α-cholestan-3β-ol, which allowed us to propose a β orientation of OH group at C-3 (Figure 4). The stereochemistry of the side chain moiety was determined by comparison of the 1H and 13C NMR spectral data with those of hippuristerone A.

The molecular formula of hippuristeroketal A (5) was found to be C35H58O9, as deduced from HRESIMS data. Its IR spectrum revealed the absorptions for hydroxyl (νmax 3471 cm−1) and ester carbonyl (νmax 1731 cm−1) groups. NMR data (Tables 1 and 2) of 5 indicated the presence of a ketal (δC 100.7), two ester cabonyls, two oxygenated sp3 methines, an oxygenated sp3 methylene, three oxygenated sp3 quaternary carbons, two secondary methyls, four tertiary methyls, six non-oxygenated sp3 methines, eight non-oxygenated sp3 methylenes, and two non-oxygenated sp3 quaternary carbons. By comparison of the NMR spectroscopic data (Tables 1 and 2) of 5 resembled those of hippuristerone F [14] with the absence of ketone carbon at δC 211.6 and the presence of two methoxyl signals [δH 3.12 (3H, s), 3.02 (3H, s) and δC 47.6 (CH3), 47.5 (CH3)] in the molecule. The HMBC correlations (Figure 3) of the methoxyl protons with C-3 [δC 100.7 (qC)], suggesting that C-3 was substituted by two methoxy groups. The stereochemistry of the side chain moiety was determined by comparison of the 1H and 13C NMR spectral data with those of hippuristerones F, H, and I previously isolated from I. hippuris [16]. Compound 5 was not an artifact because 1H NMR signals for the dimethylketal were observed before MeOH treatment.

Metabolites 1–5 were not cytotoxic against P-388 (mouse lymphocytic leukemia), HT-29 (human colon adenocarcinoma) tumor cells, and human embryonic lung (HEL) cells with IC50 values greater than 50 μg/mL. The anti-HCMV activity and cytotoxicity against of selected cell lines of 1–5 were evaluated. Compound 2 exhibited inhibitory activity against HCMV, with an EC50 values of 6.0 μg/mL.

 3. Experimental Section 3.1. General Experimental Procedures

Optical rotations were determined with a JASCO P1020 digital polarimeter. Ultraviolet (UV) and infrared (IR) spectra were obtained on JASCO V-650 and JASCO FT/IR-4100 spectrophotometers, respectively. NMR spectra were recorded on a Varian MR 400 NMR spectrometer at 400 MHz for 1H and 100 MHz for 13C or on a Varian Unity INOVA 500 FT-NMR spectrometer at 500 MHz for 1H and 125 MHz for 13C, respectively. 1H NMR chemical shifts are expressed in δ (ppm) referring to the solvent peaks δH 7.27 and 7.15 for CDCl3 and C6D6, respectively, and coupling constants are expressed in Hz. 13C NMR chemical shifts are expressed in δ (ppm) referring to the solvent peaks δC 77.0 and 128.0 for CDCl3 and C6D6, respectively. ESI-MS were recorded by ESI FT-MS on a Bruker APEX II mass spectrometer. Silica gel 60 (Merck, Germany, 230–400 mesh) and LiChroprep RP-18 (Merck, 40–63 μm) were used for column chromatography. Precoated silica gel plates (Merck, Kieselgel 60 F254, 0.25 mm) and precoated RP-18 F254s plates (Merck) were used for thin-layer chromatography (TLC) analysis. High-performance liquid chromatography (HPLC) was carried out using a Hitachi L-7100 pump equipped with a Hitachi L-7400 UV detector at 220 nm together with a semi-preparative reversed-phase column (Merck, Hibar LiChrospher RP-18e, 5 μm, 250 × 25 mm).

 3.2. Biological Material

The octocoral I. hippuris was collected by hand using scuba at Orchid Island, 70 km off the southeastern coast of Taiwan, in August 2008 at a depth of 9 m and stored in a freezer until extraction. The voucher specimen (LY-19) was identified by Prof. Chang-Feng Dai, National Taiwan University and deposited at the Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Taiwan.

 3.3. Extraction and Isolation

A specimen of octocoral I. hippuris (4.0 kg, wet weight) was minced and exhaustively extracted with acetone (3 × 3 L) at room temperature. The combined acetone extracts was then partitioned between H2O and EtOAc. The resulting EtOAc extract (25.6 g) was subjected to gravity silica gel 60 column chromatography (Si 60 CC) using n-hexane–EtOAc and EtOAc–MeOH of increasing polarity, to give 44 fractions. Fraction 28 (0.86 g), eluted with n-hexane–EtOAc (1:6), was further subjected to Si 60 CC (n-hexane–EtOAc, 5:3) to give 4 subfractions. A subfraction 28-2 (105 mg) was separated by a RP-18 flash column (MeOH–H2O, 75:25 to 100:0) to give four fractions. In turn, a subfraction 28-2-2, eluted with MeOH–H2O (80:20), was further purified by RP-18 HPLC (MeOH–H2O–MeCN, 80:20:5) to affford 1 (3.0 mg) and 4 (0.5 mg). Similarly, the subfraction 28-3 (112 mg) was further subjected to a RP-18 flash column (MeOH–H2O, 75:25 to 100:0) to give five subfractions. A subfraction 28-3-2 (112 mg), eluted with MeOH–H2O (70:30), was further purified by RP-18 HPLC (MeOH–H2O–MeCN, 75:25:5) to obtain 1 (0.2 mg) and 4 (0.3 mg). Likewise, the subfraction 28-3-3, eluted with MeOH–H2O (80:20), was purified by RP-18 HPLC (MeOH–H2O–MeCN, 75:25:5) to give 5 (1.2 mg). Fraction 29 (0.41 g), eluted with n-hexane–EtOAc (1:7), was subjected to Si 60 CC (n-hexane–EtOAc, 8:2 to 2:8) to give four subfractions. A subfraction 29-3 (309 mg), eluted with n-hexane–EtOAc (2:7), was further fractionated by a RP-18 flash column (MeOH–H2O, 60:40 to 100:0) to give four subfractions. A subfraction 29-3-2, eluted with MeOH–H2O (75:25), was further purified by RP-18 HPLC (MeOH–H2O, 70:30) to afford 3 (1.0 mg), 2 (1.2 mg), and 1 (0.2 mg).

Hipposterone M (1): White amorphous powder; [α]D 25 −8 (c 0.1, CHCl3); IR (neat) νmax 3454, 2954, 2922, 1733, 1717, 1558, 1456, 1374, 1238, 1152, 1019 cm−1; 1H NMR (CDCl3, 400 MHz) and 13C NMR (CDCl3, 100 MHz) data in Tables 1 and 2; HRESIMS m/z 599.3556 [M + Na]+ (calcd for C33H52O8Na, 599.3560).

Hipposterone N (2): White amorphous powder; [α]D 25 −11 (c 0.1, CHCl3); IR (neat) νmax 3463, 2970, 2933, 1731, 1715, 1374, 1244, 1021, 735 cm−1; 1H NMR (CDCl3, 400 MHz) and 13C NMR (CDCl3, 100 MHz) data in Tables 1 and 2; HRESIMS m/z 557.3452 [M + Na]+ (calcd for C31H50O7Na, 557.3454).

Hipposterone O (3): White amorphous powder; [α]D 25 −5 (c 0.1, CHCl3); IR (neat) νmax 3471, 2974, 2939, 1731, 1449, 1373, 1247, 1023, 739 cm−1; 1H NMR (CDCl3, 400 MHz) and 13C NMR (CDCl3, 100 MHz) data in Tables 1 and 2; HRESIMS m/z 657.3616 [M + Na]+ (calcd for C35H54O10Na, 657.3614).

Hipposterol G (4): White amorphous powder; [α]D 25 +5 (c 0.1, CHCl3); IR (neat) νmax 3471, 2928, 2860, 1734, 1454, 1371, 1244, 1023, 736 cm−1; 1H NMR (CDCl3, 500 MHz) and 13C NMR (CDCl3, 125 MHz) data in Tables 1 and 2; HRESIMS m/z 643.3819 [M + Na]+ (calcd for C35H56O9Na, 643.3822).

Hppuristeroketal A (5): White amorphous powder; [α]D 25 +21 (c 0.1, CHCl3); IR (neat) νmax 3471, 2974, 1731, 1373, 1248, 1041, 739 cm−1; 1H NMR (C6D6, 500 MHz) and 13C NMR (CDCl3, 125 MHz) data in Tables 1 and 2; HRESIMS m/z 645.3975 [M + Na]+ (calcd for C35H58O9Na, 645.3978).

 3.4. Cytotoxicity Assay

Cytotoxicity was determined on P-388 (mouse lymphocytic leukemia), HT-29 (human colon adenocarcinoma), and A-549 (human lung epithelial carcinoma) tumor cells using a modification of the MTT colorimetric method according to a previously described procedure [19,20]. The provision of the P-388 cell line was supported by J.M. Pezzuto, formerly of the Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago. HT-29 and A-549 cell lines were purchased from the American Type Culture Collection.

 3.5. Anti-HCMV Assay

To determine the effects of natural products upon HCMV cytopathic effect (CPE), confluent human embryonic lung (HEL) cells grown in 24-well plates were incubated for 1 h in the presence or absence of various concentrations of tested natural products. Then, cells were infected with HCMV at an input of 1000 pfu (plaque forming units) per well of 24-well dish. Antiviral activity was expressed as IC50 (50% inhibitory concentration), or compound concentration required to reduce virus induced CPE by 50% after 7 days as compared with the untreated control. To monitor the cell growth upon treating with natural products, an MTT-colorimetric assay was employed [21].

 Acknowledgments

This research was financially supported by grants from the National Science Council (NSC99-2628-B-110-002-MY3) and Ministry of Education of Taiwan awarded to C.-Y.D.

Samples Availability: Not available.

 References KazlauskasRMurphyPTQuinnRJWellsRJSchonholzerPAn unusual steroid from gorgonian Isis hippurisTetrahedron Lett19775044394442 HigaTTanakaJTsukitaniYKikuchiHHippuristanols, cytotoxic polyoxygenated steroids from the gorgonian Isis hippurisChem. Lett19811116471650 GonzalezNBarralMARodriguezJJimenezCNew cytotoxic steroids from the gorgonian Isis hippurisTetrahedron2001573487349710.1016/S0040-4020(01)00223-X RaoCBRamanaKVRaoDVFahyEFaulknerDJMetabolites of the gorgonian Isis hippuris from IndiaJ. Nat. Prod19885195495810.1021/np50059a023 ShenYCPrakashCVSChangYTHungMCChenSJChenHJHsuMCBioactive steroids from the Formosan gorgonian Isis hippurisChin. Pharm. J20005234135110.1211/0022357001773896 SheuJHChaoCHWangGHHungKCDuhCYChiangMYWuYCWuCCThe first A-nor-hippuristanol and two novel 4,5-secosuberosanoids from the gorgonian Isis hippurisTetrahedron Lett2004456413641610.1016/j.tetlet.2004.07.001 ChaoCHHuangLFYangYLSuJHWangGHChiangMYWuYCDaiCFSheuJHPolyoxygenated steroids from the gorgonian Isis hippurisJ. Nat. Prod20056888088510.1021/np050033y15974612 QiSHMiaoLGaoCHXuYZhangSQianPYNew steroids and a new alkaloid from the gorgonian Isis minorbrachyblasta: structures, cytotoxicity, and antilarval activityHelv. Chim. Acta20109351151610.1002/hlca.200900250 HigaTTanakaJTachibanaK18-Oxygenated polyfunctional steroids from the horgonian Isis hippurisTetrahedron Lett1981222777278010.1016/S0040-4039(01)90550-7 TanakaJTriantoAMusmanMIssaHHOhtaniIIIchibaTHigaTYoshidaWYScheuerPJNew polyoxygenated steroids exhibiting reversal of multidrug resistance from the gorgonian Isis hippurisTetrahedron2002586259626610.1016/S0040-4020(02)00625-7 TanakaJHigaTTachibanaKIwashitaTGorgost-5-ene-3β,7α,11α,12β-tetraol 12-monoacetate, a new marine sterol from the gorgonian Isis hippurisChem Lett198212951296 ShenYCPrakashCVSChangYTTwo new polyhydroxysteroids from the gorgonian Isis hippurisSteroids20016672172510.1016/S0039-128X(01)00098-811546560 UddinMHHanifNTriantoAAgarieYHigaTTanakaJFour new polyoxygenated gorgosterols from the gorgonian Isis hippurisNat. Prod. Res20112558559110.1080/14786419.2010.48530321409719 ChaoCHHuangLFWuSLSuJHHuangHCSheuJHSteroids from the gorgonian Isis hippurisJ. Nat. Prod2005681366137010.1021/np050200u16180815 SheuJHChenSPSungPJChiangMYDaiCFHippuristerone A, a novel polyoxygenated steroid from the gorgonian Isis hippurisTetrahedron Lett2000417885788810.1016/S0040-4039(00)01348-4 SheuJHHuangLFChenSPYangYLSungPJWangGHSuJHChaoCHHuWPWangJJHippuristerones E–I, new polyoxygenated steroids from the gorgonian coral Isis hippurisJ. Nat. Prod20036691792110.1021/np020602r12880306 BordeleauMEMoriAObererMLindqvistLChardLSHigaTBelshamGJWagnerGTanakaJPelletierJFunctional characterization of IRESes by an inhibitor of the RNA helicase eIF4ANat. Chem. Biol2006221322010.1038/nchembio77616532013 LindqvistLObererMReibarkhMCencicRBordeleauMEVogtEMarintchevATanakaJFagottoFAltmannMSelective pharmacological targeting of a DEAD Box RNA helicasePLoS One20083e158310.1371/journal.pone.000158318270573 GeranRIGreenbergNHMacDonaldMMSchumacherAMAbbottBJProtocols for screening chemical agents and natural products against animal tumors and other biological systemsCancer Chemother. Rep19723191 HouRSDuhCYChiangMYLinCNSinugibberol, a new cytotoxic cembranoid diterpene from the soft coral Sinularia gibberosaJ. Nat. Prod1995581126113010.1021/np50121a0267561904 StevensMBalzariniJTabarriniOAndreiGSnoeckRCecchettiVFravoliniADe ClercqEPannecouqueCCell-dependent interference of a series of new 6-aminoquinolone derivatives with viral (HIV/CMV) transactivationJ. Antimicrob. Chemother20055684785510.1093/jac/dki32816150861 Figures and Tables

Bamboo coral Isis hippuris.

Structures of compounds 1–5.

COSY and HMBC correlations of compounds 1–5.

NOESY correlations of compounds 1 and 4.

13C NMR data for compounds 1–5.

C# 1, a δC, type 2, a δC, type 3, a δC, type 4, b δC, type 5, c δC, type
1 38.3, CH2 38.3, CH2 38.2, CH2 36.7, CH2 35.6, CH2
2 38.1, CH2 38.1, CH2 38.0, CH2 31.4, CH2 29.2, CH2
3 211.7, qC 211.7, qC 211.5, qC 71.2, CH 100.7, qC
4 44.5, CH2 44.5, CH2 44.5, CH2 38.0, CH2 36.2, CH2
5 46.5, CH 46.5, CH 46.4, CH 44.7, CH 43.0, CH
6 28.6, CH2 28.5, CH2 28.5, CH2 28.3, CH2 28.8, CH2
7 31.7, CH2 31.7, CH2 31.5, CH2 31.9, CH2 32.7, CH2
8 34.5, CH 34.4, CH 34.4, CH 34.5, CH 35.1, CH
9 53.1, CH 53.6, CH 53.4, CH 54.0, CH 55.1, CH
10 35.7, qC 35.7, qC 35.6, CH 35.5, qC 36.4, qC
11 21.0, CH2 21.0, CH2 21.5, CH2 21.4, CH2 22.0, CH2
12 30.6, CH2 31.0, CH2 32.4, CH2 32.2, CH2 33.3, CH2
13 46.8, qC 46.7, qC 45.6, qC 45.6, qC 46.5, qC
14 47.7, CH 48.7, CH 49.2, CH 48.7, CH 50.3, CH
15 33.3, CH2 33.3, CH2 33.5, CH2 33.4, CH2 34.4, CH2
16 70.0, CH 70.1, CH 70.3, CH 70.1, CH 71.1, CH
17 80.0, qC 79.7, qC 77.2, qC 77.7,qC 78.6, qC
18 61.9, CH2 61.9, CH2 63.5, CH2 63.5, CH2 64.3, CH2
19 11.3, CH3 11.4, CH3 11.4, CH3 12.2, CH3 12.0, CH3
20 67.1, qC 67.5, qC 66.7, qC 66.4, qC 67.3, qC
21 16.1, CH3 15.9, CH3 16.1, CH3 16.2, CH3 17.1, CH3
22 77.2, CH 77.2, CH 77.2, CH 77.2, CH 78.1, CH
23 33.5, CH 32.9, CH 32.5, CH 33.6, CH 33.6, CH
24 39.9, CH 41.7, CH 38.8, CH 40.1, CH 42.2, CH
25 85.5, qC 73.7, qC 74.2, qC 85.6, qC 73.5, qC
26 23.2, CH3 30.9, CH3 71.0, CH2 22.8, CH3 31.2, CH3
27 25.1, CH3 25.8, CH3 20.3, CH3 25.1, CH3 25.9, CH3
28 10.4, CH3 11.4, CH3 10.9, CH3 10.5, CH3 11.7, CH3
29 11.9, CH3 12.1, CH3 12.3, CH3 11.9, CH3 12.6, CH3
OAc 20.9, CH3 20.9, CH3 21.2, CH3 21.2, CH3 21.1, CH3
171.6, qC 171.6, qC 171.1, qC 171.0, qC 170.6, qC
22.6, CH3 21.1, CH3 21.0, CH3 20.9, CH3
169.8, qC 171.3, qC 171.2, qC 171.4, qC
21.1, CH3 22.7, CH3
170.8, qC 169.9, qC
OMe 47.6, CH3
47.5, CH3

Spectra were measured in CDCl3 (100 MHz);

Spectra were measured in CDCl3 (125 MHz);

Spectra were measured in C6D6 (125 MHz).

1H NMR data for compounds 1–5.

H# 1, δH (J in Hz) a 2, δH (J in Hz) a 3, δH (J in Hz) a 4, δH (J in Hz) b 5, δH (J in Hz) c
1 α: 1.39 m α: 1.35 m α: 1.32 m α: 1.02 m α: 1.33 m
β: 2.02 m β: 2.00 m β: 1.97 m β: 1.69 m β: 1.06 m
2 α: 2.32 m α: 2.31 m α: 2.31 m α: 1.82 m α: 1.86 m
β: 2.38 m β: 2.39 m β: 2.37 m β: 1.41 m β: 1.41 m
3 3.60 m
4 α: 2.12 dd ovl α: 2.09 dd ovl α: 2.12 dd ovl α: 1.58 m α: 1.86 dd (13.6, 3.6)
β: 2.28 t (13.6) β: 2.27 t (13.6) β: 2.26 t (13.6) β: 1.29 m β: 1.41 dd ovl
5 1.56 m 1.54 m 1.55 m 1.54 m 1.34 m
6 1.38 m 1.38 m 1.39 m 1.34 m 1.08 m
7 1.79 m 1.78 m 1.82 m 1.78 m 1.54 m
0.93 m 0.92 m 0.95 m 0.91 m 0.67 m
8 1.58 m 1.58 m 1.72 m 1.67 m 1.45 m
9 0.85 m 0.74 m 0.81 m 0.75 m 0.70 m
11 α: 1.66 m α: 1.65 m α: 1.63 m α: 1.60 m α: 1.48 m
β: 1.48 m β: 1.44 m β: 1.33 m β: 1.23 m β: 1.23 m
12 α: 1.28 m α 1.28 m α: 1.34 m α: 1.38 m α: 1.44 m
β: 2.44 m β: 2.44 m β: 2.16 m β: 2.17 m β: 2.28 m
14 1.36 m 1.18 m 1.23 m 1.31 m 1.28 m
15 α: 2.23 m α: 2.24 m α: 2.21 m α: 2.21 m α: 2.22 m
β: 1.44 m β: 1.46 m β: 1.48 m β: 1.46 m β: 1.59 m
16 4.10 t (7.2) 4.13 t (7.6) 4.06 t (7.6) 4.04 dd (8.0, 7.5) 4.38 t (7.5)
18 3.75 t (10.4) 3.74 t (11.2) 4.23 d (11.6) 4.27 d (11.5) 4.55 d (11.5)
3.94 d (11.6) 3.94 dd (11.6, 2.4) 4.30 d (11.6) 4.20 d (11.5) 4.49 d (11.5)
19 1.02 s 1.02 s 1.02 s 0.82 s 0.64 s
21 1.64 s 1.66 s 1.60 s 1.59 s 1.84 s
22 4.62 d (10.8) 4.60 d (10.8) 4.66 d (10.8) 4.67 d (11.0) 5.04 d (10.5)
23 2.28 m 2.47 m 2.50 m 2.29 m 2.43 m
24 1.97 q (8.0) 1.47 q (6.8) 1.64 q (6.8) 1.92 q (7.0) 1.55 q (7.5)
26 1.56 s 1.24 s 3.89 d (11.6) 1.56 s 0.88 s
4.04 d (11.6)
27 1.43 s 1.21 s 1.18 s 1.46 s 0.78 s
28 0.90 d (8.0) 0.90 d (6.8) 0.88 d (6.8) 0.91 d (7.0) 0.65 d (7.5)
29 0.88 d (6.4) 0.86 d (6.4) 0.88 d (6.8) 0.87 d (7.0) 0.80 d (7.0)
OAc 2.14 s, 1.99 s 2.14 s 2.07 s, 2.13 s, 2.13 s 2.06 s, 2.00 s, 2.13 s 1.76 s, 1.69 s
OMe 3.12 s, 3.02s
OH-16 3.36 s 3.43 s 3.27 br s 3.19 br s 3.83 br s
OH-18 2.44 d ovl 3.46 d ovl

Spectra were measured in CDCl3 (400 MHz);

Spectra were measured in CDCl3 (500 MHz);

Spectra were measured in C6D6 (500 MHz).