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1.
Guangtong Chen Xue Yang Shaojun Nong Min Yang Bohui Xu Wei Zhang 《Biotechnology letters》2013,35(3):439-443
Microbial transformation of 20(S)-protopanaxadiol (1) by Mucor racemosus AS 3.205 yielded two novel hydroperoxylated metabolites and three known hydroxylated metabolites. The structures of the metabolites were identified as 26-hydroxyl-20(S)-protopanaxadiol (2), 23,24-en-25-hydroxyl-20(S)-protopanaxadiol (3), 25,26-en-24(R)-hydroperoxyl-20(S)-protopanaxadiol (4), 23,24-en-25-hydroperoxyl-20(S)-protopanaxadiol (5), and 25-hydroxyl-20(S)-protopanaxadiol (6). 4 and 5 are new compounds. Metabolites 2, 4, and 5 showed the more potent inhibitory effects against DU-145 and PC-3 cell lines than the substrate. 相似文献
2.
Lin Yang Runjiang Qu Jungui Dai Xiaoguang Chen 《Journal of Molecular Catalysis .B, Enzymatic》2007,46(1-4):8-13
Mucor genevensis were used to bioconvert sinenxan A [2α,5α,10β,14β-tetraacetoxy-taxa-4(20),11-diene], a taxoid isolated from callus tissue cultures of Taxus spp., and 10 metabolites were obtained. On the basis of chemical and spectroscopic data analyses, their structures were determined as 10β-methoxy-2α,5α,14β-triacetoxy-taxa-4(20),11-diene (2), 10β-hydroxy-2α,5α,14β-triacetoxy-taxa-4(20),11-diene (3), 2α,5α,10β,14β-tetraacetoxy-4β,20-epoxy-taxa-11(12)-ene (4), 6α-hydroxy-2α,5α,10β,14β-tetraacetoxy-taxa-4(20),11-diene (5), 9α-hydroxy-2α,5α,10β,14β-tetraacetoxy-taxa-4(20),11-diene (6), 10β-hydroxy-2α,5α,14β-triacetoxy-4β,20-epoxy-taxa-11(12)-ene (7), 6α,10β-dihydroxy-2α,5α,14β-triacetoxy-taxa-4(20),11-diene (8), 6α-hydroxy-2α,5α,10β,14β-tetraacetoxy-4β,20-epoxy-taxa-11(12)-ene (9), and 9α,10β-dihydroxy-2α,5α,14β-triacetoxy-taxa-4(20),11-diene (10), and 9α,10β-O-(propane-2,2-diyl)-2α,5α,14β-triacetoxy-taxa-4(20),11-diene (11). Among them, metabolites 2, 4, and 9 were three new compounds. The three major metabolites 2, 3, and 4 along with 1 were pharmacologically evaluated for their multi-drug resistance (MDR) reversal activities towards taxol-resistant A549 tumor cells, and the results showed that 4 possessed about two-fold activity as verapamil, while 2, and 3 possessed lower activity than verapamil and 1. 相似文献
3.
In recent years several 15β-hydroxysteroids have emerged pathognomonic of adrenal disorders in human neonates of which 3α,15β,17α-trihydroxy-5β-pregnan-20-one (2) was the first to be identified in the urine of newborn infants affected with congenital adrenal hyperplasia. In this investigation we report the synthesis of the three remaining 3ξ,5ξ-isomers, namely 3α,15β,17α-trihydroxy-5α-pregnan-20-one (3), 3β,15β,17α-trihydroxy-5α-pregnan-20-one (7) and 3β,15β,17α-trihydroxy-5β-pregnan-20-one (8) for their definitive identification in pathological conditions in human neonates. 3β,15β-Diacetoxy-17α-hydroxy-5-pregnen-20-one (11), a product of chemical synthesis was converted to the isomeric 3 and 7, while conversion of 15β,17α-dihydroxy-4-pregnen-3,20-dione (4), a product of microbiological transformation, resulted in the preparation of 8. In brief, selective acetate hydrolysis of 11 gave 15β-acetoxy-3β,17α-dihydroxy-5-pregnen-20-one (12) which on catalytic hydrogenation gave 15β-acetoxy-3β,17α-dihydroxy-5α-pregnan-20-one (13) a common intermediate for the synthesis of the 3β(and α),5α-isomers. Hydrolysis of the 15β-acetate gave 7, whereas oxidation with pyridinium chlorochromate gave 15β-acetoxy-17α-hydroxy-5α-pregnan-3,20-dione (14) which on reduction with
-Selectride and hydrolysis of the 15β-acetate gave 3. Finally, hydrogenation of 4 gave 15β,17α-dihydroxy-5β-pregnan-3,20-dione (10) which on reduction with
-Selectride gave 8. 相似文献
4.
Seven hydroxylates of 20(S)-protopanaxatriol (1) transformed by Absidia corymbifera AS 3.3387 were isolated and identified by spectral methods including 2D-NMR. Among them, 7β-hydroxyl-20(S)-protopanaxatriol (2), 7α-hydroxyl-20(S)-protopanaxatriol (3), and 7β, 15α-dihydroxyl-20(S)-protopanaxatriol (7) are new compounds. The metabolites 2, 6, 7, and 8 showed the more potent inhibitory effects against DU-145 and PC-3 cell lines than the substrate. 相似文献
5.
Jungui Dai Lin Yang Jun-ichi Sakai Masayoshi Ando 《Journal of Molecular Catalysis .B, Enzymatic》2005,33(3-6):87-91
Biotransformation of chinensiolide B, 10α-hydroxy-1α,5α,15-H-3-oxoguaia-11(13)-en-6α,12-olide (1), yielded three selectively reduced products, 3β,10α-dihydroxy-1α,5α,15α-H-guaia-11(13)-en-6α,12-olide (2), 3α,10α-dihydroxy-1α,5α,15α-H-guaia-11(13)-en-6α,12-olide (3), and 3β,10α-dihydroxy-1α,5α,11β,15α-H-guaia-6α,12-olide (4) by the cell suspension cultures of Catharanthus roseus. 2 and 3 were also obtained from 1 incubated with cell cultures of a fungus Abisidia coerulea IFO 4011 and Platycodon grandiflorum, respectively. Among them, 2, 3 are two new compounds. The three products, 2–4, along with 1 were preliminarily evaluated for their in vitro cytotoxic activity against 3 cell lines (HepG2, WI-38 and VA-13) and all showed potent inhibitory effects on the cell proliferation. Of the four compounds, 3 was the most toxic to the three cell lines tested with IC50 values of 22.7, 0.33 and 3.30 μM, respectively. 相似文献
6.
Chemical examination of the ethyl acetate solubles of the CH3OH:CH2Cl2 (1:1) extract of the roots of Ceriops decandra collected from Kauvery estuary resulted in the isolation of four new diterpenoids, ceriopsins A–D (1–4). The structures of the new diterpenoids were elucidated by a study of their physical and spectral data as methyl 17-hydroxy-16-oxobeyeran-18-oate (1), methyl 16(R)-16,17-dihydroxybeyeran-18-oate (2), 1β,15(S)-isopimar-7-ene-1,15,16-triol (3), and 8,15(R)-epoxypimarane-1β,16-diol (4). 相似文献
7.
Andrew S. Lamm Avril R.M. Chen William F. Reynolds Paul B. Reese 《Journal of Molecular Catalysis .B, Enzymatic》2009,59(4):292-296
Santonin (1) was incubated with separate growing cultures of Aspergillus niger ATCC 9142, Mucor plumbeus ATCC 4740, Whetzelinia sclerotiorum ATCC 18687, Cunninghamella echinulata var. elegans ATCC 8688a and Phanerochaete chrysosporium ATCC 24725. Three novel metabolites were isolated: 11β,13-dihydroxysantonin (3), 6,7-dehydosantonin (5) and 3,6-dihydroxy-9-keto-9,10-seco-selina-1,3,5(10)-trien-12-oic acid-12,6-lactone (7). 11β-Hydroxysantonin (2), 14-hydroxysantonin (4) and 3,6,9-trihydroxy-9,10-seco-selina-1,3,5(10)-trien-12-oic acid-12,6-lactone (6) were also isolated. Hydroxylation at C-9 followed by a retro-aldol reaction was postulated to have produced 6 and 7. Through the synthesis and fermentation of the santonin analogues: tetrahydrosantonin (8) and α-desmotroposantonin (12), several new compounds were obtained; the most significant being 9-keto-desmotroposantonin (14), which was indicative of C-9 monohydroxylation. 相似文献
8.
Di-nor-benzofuran neolignan aldehydes, Δ7-3,4-methylenedioxy-3′-methoxy-8′,9′-dinor-4′,7-epoxy-8,3′-neolignan-7′-aldehyde (ocophyllal A) 1, Δ7-3,4,5,3′-tetramethoxy-8′,9′-dinor-4′,7-epoxy-8,3′-neolignan-7′-aldehyde (ocophyllal B) 2, and macrophyllin-type bicyclo[3.2.1]octanoid neolignans (7R, 8R, 3′S, 4′S, 5′R)-Δ8′-4′-hydroxy-5′-methoxy-3,4-methylenedioxy-2′,3′,4′,5′-tetrahydro-2′-oxo-7.3′,8.5′-neolignan (ocophyllol A) 3, (7R, 8R, 3′S, 4′S, 5′R)-Δ8′-4′-hydroxy-3,4,5′-trimethoxy-2′,3′,4′,5′-tetrahydro-2′-oxo-7.3′,8.5′-neolignan (ocophyllol B) 4, (7R, 8R, 3′S, 4′S, 5′R)-Δ8′-4′-hydroxy-3,4,5,5′-tetramethoxy-2′,3′,4′,5′-tetrahydro-2′-oxo-7.3′,8.5′-neolignan (ocophyllol C) 5, as well as 2′-epi-guianin 6 and (+)-licarin B 7, were isolated and characterized from leaves of Ocotea macrophylla (Lauraceae). The structures and configuration of these compounds were determined by extensive spectroscopic analyses. Inhibition of platelet activating factor (PAF)-induced aggregation of rabbit platelets were tested with neolignans 1–7. Although compound 6 was the most potent PAF-antagonist, compounds 3–5 showed some activity. 相似文献
9.
M. Sautour F. Canon T. Miyamoto A. Dongmo M.-A. Lacaille-Dubois 《Biochemical Systematics and Ecology》2008,36(7):559-563
Phytochemical investigation of the rhizome of Dioscorea dumetorum has led to the isolation by several chromatographic steps on normal and reversed phase silica gel of a new ecdysteroid, (20R)-5β,11α,20-trihydroxyecdysone (1), and two known ecdysteroids, ajugasterone C (2) and herkesterone (3). Their structures were determined by spectroscopic methods including 1D- and 2D-NMR (COSY, TOCSY, HSQC and HMBC). This is the first report on the occurrence of phytoecdysteroids in the Dioscoreaceae family. These compounds were devoid of antifungal activity against three Candida species (Candida albicans, Candida glabrata and Candida tropicalis, MIC > 200 μg/ml). 相似文献
10.
Shwu-Fen Chang Bo-Hon Chou Li-Ming Yang Feng-Lin Hsu Wen-Kuang Lin Yi Ho Shwu-Jiuan Lin 《Bioorganic & medicinal chemistry》2009,17(17):6348-6353
Microbial transformation of isosteviol oxime (ent-16-E-hydroxyiminobeyeran-19-oic acid) (2) with Aspergillus niger BCRC 32720 and Absidia pseudocylindrospora ATCC 24169 yielded several compounds. In addition to bioconverting the d-ring to lactone and lactam moieties, 4α-carboxy-13α-hydroxy-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactone (7) and 4α-carboxy-13α-amino-13,16-seco-ent-19-norbeyeran-16-oic acid 13,16-lactam (10), one known compound, ent-1β,7α-dihydroxy-16-oxo-beyeran-19-oic acid (6), and five new compounds, ent-7α-hydroxy-16-E-hydroxyiminobeyeran-19-oic acid (3), ent-1β,7α-dihydroxy-16-E-hydroxyiminobeyeran-19-oic acid (4), ent-1β-hydroxy-16-E-hydroxyiminobeyeran-19-oic acid (5), ent-8β-cyanomethyl-13-methyl-12-podocarpen-19-oic acid (8), and ent-8β-cyanomethyl-13-methyl-13-podocarpen-19-oic acid (9), were isolated from the microbial transformation of 2. Elucidation of the structures of these isolated compounds was primarily based on 1D and 2D NMR, and HRESIMS data, and 3–5 were further confirmed by X-ray crystallographic analyses. Additionally, the inhibitory effects of all of these compounds were evaluated on NF-κB and AP-1 activation in LPS-stimulated RAW 264.7 macrophages. Among the compounds tested, 5 and 10 significantly inhibited NF-κB activation, with 5 showing equal potency to dexamethasone; 3 and 6–9 significantly inhibited AP-1 activation, particularly 8, which showed more inhibitory activity than dexamethasone. 相似文献
11.
Bo Zhang Sheng-Ping Yang Sheng Yin Chuan-Rui Zhang Yan Wu Jian-Min Yue 《Phytochemistry》2009,70(10):1305-1308
Four limonoids, 1-O-deacetyl-6-deoxykhayanolide E (1), 1-O-deacetyl-2α-hydroxykhayanolide E (2), 3-acetyl-khayalactone (3), 11α-acetoxy-2α-hydroxy-6-deoxy-destigloylswietenine acetate (4), along with 12 known limonoids, were isolated from the stems of Khaya ivorensis. Their structures were elucidated on the basis of spectroscopic analysis. 相似文献
12.
Yi-Pei Lin Tai-Yuan Chen Hsiang-Wen Tseng Mei-Hsien Lee Shui-Tein Chen 《Phytochemistry》2009,70(9):1173-1181
A platform for screening drugs for their ability to protect neuronal cells against cytotoxicity was developed. Nerve growth factor (NGF) differentiates PC12 cells into nerves, and these differentiated PC12 cells enter apoptosis when challenged with 6-hydroxydopamine (6-OHDA). A screening spectrophotometer was used to assay cytotoxicity in these cells; pretreatment with test samples allowed identification of compounds that protected against this neuronal cytotoxicity. The 95% ethanol extract of Phoenix hanceana Naudin var. formosana Beccari. (PH) showed potential neuroprotective activity in these assays. The PH ethanol extract was further fractionated by sequential partitioning with n-hexane, ethyl acetate (EtOAc), n-butanol (n-BuOH), and water. Subsequent rounds of assaying resulted in the isolation of ten constituents, and their structures were characterized by various spectroscopic techniques and identified by comparison with previous data as: isoorientin (1), isovitexin (2), veronicastroside (3), luteolin-7-O-β-d-glucopyranoside (4), isoquercitrin (5), tricin-7-neohesperidoside (6), tricin-7-O-β-d-gluco-pyranoside (7), (+)-catechin (8), (−)-epicatechin (9), and orientin 7-O-β-d-glucopyranoside (10). Among these compounds, isovitexin (2), luteolin-7-O-β-d-glucopyranoside (4) and (+)-catechin (8) showed significant neuroprotective activity in cell viability (WST-8 reduction), anti-apoptosis (Annexin V-FITC/propidium iodide double-labeled flow cytometry), and cellular ROS scavenging assays (besides isovitexin (2)), as well as a decreased caspase-8 activity in 6-OHDA-induced PC12 cells. Hence, isovitexin (2), luteolin-7-O-β-d-glucopyranoside (4), and (+)-catechin (8) protected PC12 cells from 6-OHDA-induced apoptotic neurotoxicity. 相似文献
13.
Evgenija A. Djurendi Marina P. Zavi Marija N. Saka
Jano J. anadi Vesna V. Koji Gordana M. Bogdanovi Katarina M. Penov Gai 《Steroids》2009,74(12):983-988
Starting from 3β-hydroxy-17-oxo-16,17-secoandrost-5-ene-16-nitrile (1), the new 16,17-secoandrostane derivatives 4–9 were synthesized. On the other hand, 3β-hydroxy-17-oxa-d-homoandrost-5-ene-16-one (10) yielded the new d-homo derivatives 12, 13 and 15. In vitro antiproliferative activity of selected compounds against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER−, MDA-MB-231, prostate cancer AR−, PC-3, and normal fetal lung fibroblasts, MRC-5) was evaluated. Compounds 3 and 12 showed strong antiproliferative activity against PC-3 cells, the IC50 values being 2 μM and 0.55 μM, respectively. Compounds 6 (10 μM) and 14 (9 μM) showed moderate activity against MDA-MB-231 cells. The synthesized compounds 1–3, 5–8, 10 and 12–15 were not toxic to normal fetal lung fibroblasts cells, MRC-5. 相似文献
14.
Mohamed-Elamir F. Hegazy Chika Kuwata Akihito Matsushima Ahmed A. Ahmed Toshifumi Hirata 《Journal of Molecular Catalysis .B, Enzymatic》2006,39(1-4):13
The biotransformation of sesquiterpenoids having an α,β-unsaturated carbonyl group, such as α-santonin (1), lancerodiol p-hydroxybenzoate (2), 8,9-dehydronootkatone (3), and nootkatone (4), with cultured suspension cells of Marchantia polymorpha was investigated. It was found that the CC double bond of 1 and 2 was hydrogenated to give 1,2-dihydro-α-santonin (5) and 3,4-dihydrolancerodiol p-hydroxybenzoate (6), respectively, while the allylic position of the CC double bond of 3 and 4 was hydroxylated to give 13-hydroxy-8,9-dehydronootkatone (7) and 9-hydroxynootkatone (8), respectively. 相似文献
15.
Agnieszka Glebocka Rafal R. Sicinski Lori A. Plum Hector F. DeLuca 《The Journal of steroid biochemistry and molecular biology》2007,103(3-5):310
Our recent studies with 2-(3′-hydroxypropylidene) analogs of 1α,25-dihydroxy-19-norvitamin D3 showed that this 2-substituent creates compounds with very potent biological activity. In the continuing search for vitamin D compounds with selective activity profiles, we prepared a series of 1α-hydroxy-19-norvitamin D analogs characterized by the presence of a 3′-hydroxypropylidene substituent at C-2 and a truncated side chain. These vitamin D compounds were efficiently prepared using convergent syntheses. The C,D-fragments, namely the Grundmann ketones 19, 20, 27, 36 and 37 were synthesized from the known 8β-benzoyloxy-22-aldehydes 12 and 29. These hydrindanones were subjected to Lythgoe type Wittig–Horner coupling with phosphine oxide 21, prepared by us previously, and after hydroxyl deprotection the set of 19-norvitamins 7–11 was successfully obtained. According to our expectations, all analogs (with an exception of the 20R-compound 7) have pronounced in vitro activity. When compared to the natural hormone 1α,25-(OH)2D3 (1), they show the same or only slightly reduced affinity for the vitamin D receptor while being similarly effective as 1 in differentiation of HL-60 cells into monocytes. 相似文献
16.
Roots of Anisotome pilifera yielded typical Apiaceae compounds 6,7-dimethoxy-coumarin 1 and falcarindiol 2, plus the irregular diterpenes anisotomenoic acid 3 and anisotomene alcohol 4. The new germacrane derivative 8-O-senecioyl-6β,8α,11-trihydroxygermacra-1(10)E,4E-diene 5 was also isolated and the structure established by means of high resolution mass spectrometry and 1-D and 2-D NMR spectroscopy. Distribution and chemosystematic significance of 6,8-dihydroxygermacra-1(10)E,4E-dienes and 6,8,11-trihydroxygermacra-1(10)E,4E-dienes are discussed. Additionally, leaves of A. pilifera yielded chlorogenic acid 6 and high amounts of luteolin 7-O-α-
-rhamnosyl(1→6)-β-
-glucoside 7. 相似文献
17.
M. Iqbal Choudhary Nadra Naheed Ahmed Abbaskhan Sajjad Ali Atta-ur-Rahman 《Phytochemistry》2009,70(11-12):1467-1473
Five glycosides, 2-(trans-cinnamoyloxy-methyl)-1-butene-4-O-β-d-glucopyranoside (1), 4-(6′-O-trans-cinnamoyl)-(2-hydroxymethyl-4-hydroxy-butenyl-β-d-glucopyranoside (2), 6′′-O-trans-p-coumaroyl-(4-hydroxybenzoyl)-β-d-glucopyranoside (3), 6′-O-(4-methoxy-trans-cinnamoyl) α/β-d-glucopyranose (4) 6′-O-(4′′-methoxy-trans-cinnamoyl)-kaempferol-3-β-d-glucopyranoside (7) along with six known compounds, (+)-isolariciresinol 3a-O-β-d-glucopyranoside (8) (+)-lyoniresinol 3a-O-β-d-glucopyranoside (9), apigenin 7-O-β-d-glucopyranoside (10), quercetin 3-O-β-d-glucopyranoside (11), 6′-O-cinnamoyl-α/β-d-glucopyranose (6) 6’-O-p-coumaroyl-α/β-d-glucopyranose (5) were isolated from the whole plant of Spiraea canescens. Some of these compounds showed potent radical scavenging activity in relevant non-physiological assays. Their structures were determined by NMR spectroscopic and CID mass spectrometric techniques. 相似文献
18.
Amelia P. Guevara Carolyn Vargas Hiromu Sakurai Yasuhiro Fujiwara Keiji Hashimoto Takashi Maoka Mutzuo Kozuka Yoshohiro Ito Harukuni Tokuda Hoyoku Nishino 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》1999,440(2):1270
In the course of studies on the isolation of bioactive compounds from Philippine plants, the seeds of Moringa oleifera Lam. were examined and from the ethanol extract were isolated the new O-ethyl-4-(α-
-rhamnosyloxy)benzyl carbamate (1) together with seven known compounds, 4(α-
-rhamnosyloxy)-benzyl isothiocyanate (2), niazimicin (3), niazirin (4), β-sitosterol (5), glycerol-1-(9-octadecanoate) (6), 3-O-(6′-O-oleoyl-β-
-glucopyranosyl)-β-sitosterol (7), and β-sitosterol-3-O-β-
-glucopyranoside (8). Four of the isolates (2, 3, 7, and 8), which were obtained in relatively good yields, were tested for their potential antitumor promoting activity using an in vitro assay which tested their inhibitory effects on Epstein–Barr virus-early antigen (EBV-EA) activation in Raji cells induced by the tumor promoter, 12-O-tetradecanoyl-phorbol-13-acetate (TPA). All the tested compounds showed inhibitory activity against EBV-EA activation, with compounds 2, 3 and 8 having shown very significant activities. Based on the in vitro results, niazimicin (3) was further subjected to in vivo test and found to have potent antitumor promoting activity in the two-stage carcinogenesis in mouse skin using 7,12-dimethylbenz(a)anthracene (DMBA) as initiator and TPA as tumor promoter. From these results, niazimicin (3) is proposed to be a potent chemo-preventive agent in chemical carcinogenesis. 相似文献
19.
Jie-Li Lü Jin-Ao Duan Yu-Ping Tang Nian-Yun Yang Lai-Bin Zhang 《Biochemical Systematics and Ecology》2009,37(4):405-411
Phytochemical investigation of the radix of Angelica sinensis has led to the isolation and identification of a new phthalide dimer, (3Z)-(3aR,6S,3′R,8′S)-3a.8′,6.3′-diligustilide (1), along with three known phthalide dimers, including riligustilide (2), levistolide A (3), senkyunolide O (4), and three known phthalide monomers, including 3,9-dihydroxyl-ligustilide (5), (Z)-butylidene phthalide (6), (Z)-ligustilide (7). Their structures were determined by spectroscopic methods including IR, NMR (1H NMR, 13C NMR, COSY, HSQC, HMBC and NOESY) and MS. Meanwhile, the possible biosynthesis pathways of compounds 1 and 5 were hypothesized. 相似文献
20.
The recently described [Attolino, E.; Bonaccorsi, F.; Catelani, G.; D’Andrea, F. Carbohydr. Res. 2008, 343, 2545–2556.] β-d-MaNAcp-(1→4)-β-d-Glcp thiophenyl glycosyl donor 3 was used in α-glycosylation reactions of OH-2 and OH-3 of the suitably protected p-MeO-benzyl α-l-rhamnopyranoside acceptors 7 and 8. Glycosylation of the axial OH-2 of 7 took place in high yield (76%) and with acceptable stereoselectivity (α/β = 3.4) leading to the protected trisaccharide α-11, corresponding to the repeating unit of Streptococcus pneumoniae 19F. The same reaction on equatorial OH-3 of acceptor 8 gave the trisaccharide α-15, a constituent of the repeating unit of S. pneumoniae 19A, but in lower yield (41%) and without stereoselection (α/β = 1:1.3). Utilizing the introduced orthogonal protection of OH-1 and OH-4″, the trisaccharide α-11 was transformed into a trisaccharide building block suitable for the synthesis of its phosphorylated oligomers. 相似文献