- Synthesis and biological activity evaluation of novel peroxo-bridged derivatives as potential anti-hepatitis B virus agents
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Previous studies have demonstrated that natural steroid compounds containing a peroxide bridge exhibited potential anti-hepatitis B virus activity. To continue our research, a simple and regioselective methodology, using Eosin Y as a clean photosensitized oxidation catalyst, was developed for the synthesis of a peroxide bridge in steroids. The method that using Eosin Y as the catalyst was exposed to visible light and furbished in high yields, did not involve tedious work-up or purification, and avoided using environmentally hazardous solvents. It can be regarded as a green protocol. Moreover, a series of cholesterol and β-sitosterol derivatives containing a peroxide bridge were synthesized using this method and screened for their anti-HBV activity. Among the compounds synthesized in this research, 5α,8α-cyclicobioxygen-6-vinyl-3-oxo-cholesterone (1f, 3.13 μg ml?1) had the most potent activity with inhibition rates of 77.45% ± 6.01% and 58.73% ± 8.64% on the secretion of HBsAg and HBeAg antigens, respectively, after 8 days. Further acute toxicity test showed that the LD50 value of compound 1f was 362.46 mg kg?1 after an intraperitoneal injection in mice. Moreover, structure-activity relationships of cholesterol and β-sitosterol derivatives were briefly discussed.
- Jia, Menglu,Zhao, Rui,Xu, Bing,Yan, Wenqiang,Chu, Fuhao,Gu, Hongshun,Xie, Tianxin,Xiang, Hongjun,Ren, Jian,Chen, Dagang,Wang, Penglong,Lei, Haimin
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- 5,10:13,14-Disecosteroids: novel modified steroids containing 10- and 9-membered rings
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In this paper a synthetic pathway to the modified 5,10:13,14-bisfragmentation cholestane derivatives 8-14 is described. The synthesis involves introduction of the 5α- and 14α-hydroxyl groups in the cholestane molecule and subsequent cleavage of the C(5)-C(10) bond in 5α,14α-dihydroxycholestan-3β-yl acetate (4) with the HgO/I2 reagent and the C(13)-C(14) bond in the stereoisomeric 14α-hydroxy-5,10-secosteroids 5 and 6 with the Pb(OAc)4/I2 reagent. Complete and unambiguous 1H and 13C NMR resonance assignments of the obtained secosteroids, as well as the solution conformations of their 10- and 9-membered rings were determined by extensive analysis of 1D and 2D NMR spectral data. The structures and the solid-state conformations of 5,10-secosteroids 5-7 were confirmed by X-ray analysis. All diseco-compounds have a novel 5,10:13,14-disecocholestane skeleton.
- Bjelakovi?, Mira S.,Krsti?, Natalija M.,Todorovi?, Nina,Kruni?, Aleksej,Tinant, Bernard,Dabovi?, Milan M.,Pavlovi?, Vladimir D.
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- Cyclodextrin-catalyzed extraction of fluorescent sterols from monolayer membranes and small unilamellar vesicles
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This study examined the kinetics of sterol desorption from monolayer and small unilamellar vesicle membranes to 2-hydroxypropyl-β-cyclodextrin. The sterols used include cholesterol, dehydroergosterol (ergosta-5,7,9,(11),22- tetraen-3β-ol) and cholestatrienol (cholesta-5,7,9,(11)-trien-3β-ol). Desorption rates of dehydroergosterol and cholestatrienol from pure sterol monolayers were faster (3.3-4.6-fold) than the rate measured for cholesterol. In mixed monolayers (sterol: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine 30:70 mol%), both dehydroergosterol and cholestatrienol desorbed faster than cholesterol, clearly indicating a difference in interfacial behavior of these sterols. In vesicle membranes desorption of dehydroergosterol was slower than desorption of cholestatrienol, and both rates were markedly affected by the phospholipid composition. Desorption of sterols was slower from sphingomyelin as compared to phosphatidylcholine vesicles. Desorption of fluorescent sterols was also faster from vesicles prepared by ethanol-injection as compared to extruded vesicles. The results of this study suggest that dehydroergosterol and cholestatrienol differ from cholesterol in their membrane behavior, therefore care should be exercised when experimental data derived with these probes are interpreted. (C) 2000 Elsevier Science Ireland Ltd.
- Ohvo-Rekilae, Henna,Akerlund, Bjoern,Slotte, J. Peter
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- Biogenesis-Guided Synthesis and Structural Revision of Sarocladione Enabled by Ruthenium-Catalyzed Endoperoxide Fragmentation
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Sarocladione is the first 5,10:8,9-diseco-steroid with a 14-membered macrocyclic diketone framework to have been isolated from a natural source. Herein we report a biomimetic synthesis of sarocladione in only two or seven steps from inexpensive, commercially available ergosterol. The key feature of this synthesis was a novel ruthenium-catalyzed endoperoxide fragmentation, which transformed various saturated endoperoxides into olefinic diketones by cleavage of two C?C bonds. This synthesis allowed us to unambiguously determine the structure of sarocladione and provided experimental support for its revised biosynthetic origin. This work also vividly demonstrates that consideration of the biogenesis is a powerful tool for elucidating the structures of natural products.
- Ning, Yuhan,Tian, Hailong,Gui, Jinghan
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- Syntheses of 7-dehydrocholesterol peroxides and their improved anticancer activity and selectivity over ergosterol peroxide
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7-Dehydrocholesterol peroxide (5α,8α-epidioxycholest-6-ene-3β-ol, CEP) and its acetate and hemisuccinate derivatives were synthesized and isolated for the first time, which exhibit improved anticancer activity and selectivity over ergosterol peroxide (5α,8α-epidioxy-22E-ergosta-6,22-dien-3β-ol, EEP), showing potential as new chemotherapeutic agents.
- Tian, Na-Na,Li, Chao,Tian, Na,Zhou, Qian-Xiong,Hou, Yuan-Jun,Zhang, Bao-Wen,Wang, Xue-Song
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- An environmentally benign catalytic oxidation of cholesteryl acetate with molecular oxygen by using N-hydroxyphthalimide
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A green and effective method is reported for the oxidation of cholesteryl acetate to 7-keto-cholesteryl acetate with O2 in the presence of catalytic amounts of N-hydroxyphthalimide (NHPI) under mild conditions. It was found that Co(OAc)2 could cooperate with Mn(OAc)2 to enhance the catalytic ability of NHPI resulting in better yields. This economical and environmentally-friendly method provides a potentially new way for the synthesis of the intermediate product of vitamin D3 in industry, which eliminates the use of large amounts of bromine in present route and overcomes the drawbacks of the known oxidation methods.
- Yao, Zhen,Hu, Xingbang,Mao, Jianyong,Li, Haoran
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- Structure Elucidation of Oxygenated Sterols from Eggs of Sea Hare, Aplysia juliana
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Cholest-7-en-6R-methoxy-3S,5R-diol, a new sterol, and cholest-7-en-3S,5R,6R-triol were isolated from eggs of sea hare, Aplysia juliana, and their structures and absolute configurations deduced by spectroscopic studies and chemical synthesis.
- Yamaguchi, Yoshihiro,Nakanishi, Yukio,Shimokawa, Teruyuki,Hashiguchi, Shigeru,Hayashi, Akira
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- Novel industrial method for preparing vitamin D3 by taking stigmasterol as raw material
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The invention provides a novel industrial method for preparing vitamin D3 by taking stigmasterol as a raw material. The method comprises the following steps: sequentially carrying out hydroxyl acetylation, side chain oxidation, side chain isopentane reduction and hydrogenation on stigmasterol to obtain cholesterol acetate, and then sequentially carrying out oxidation, hydrazone formation, hydrazone removal, hydrolysis, illumination and the like to obtain the vitamin D3. The invention provides a novel method for preparing vitamin D3 from stigmasterol, and the method has the advantages of mild reaction conditions and high yield, and is suitable for industrial production.
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Paragraph 0010; 0050; 0051
(2021/05/05)
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- PREPARATION OF 7-DEHYDROCHOLESTEROL USING SPECIFIC AROMATIC SOLVENTS
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The present invention relates to a new synthesis of 7- dehydrocholesterol or itsOH-protected forms of the formula I by the reaction of a compound of formula (ll)in the presence of a solvent of formula (III), comprising the step (a) wherein a salt of the formula (II) is added to a solvent of the formula (III) at a temperature of between 60 °C and the boiling point of said solvent. This process leads to a significant reduction in the level of the by-product of formula (V).
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- 7 - Dehydrogenated cholesterol and preparation method thereof
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7 - Dehydrogenated cholesterol and a preparation method thereof relate to the technical field of organic synthesis chemistry. A method for preparing 7 - dehydrogenated cholesterol, comprising performing a hydrazone reaction of 7 - arylsulfonyl hydrazone -3 - cholesterol ester to obtain an organic layer containing 7 - dehydrogenated cholesterol ester. The organic layer containing 7 - dehydrogenated cholesterol ester is subjected to saponification reaction to obtain 7 - dehydrogenated cholesterol. The hydrazone radical trapping agent is added in the hydrazone reaction process. The method can effectively inhibit the generation of aromatization impurities, wherein the total yield of the hydrazone saponification two-step reaction reaches 95% and 7 - dehydrogenated cholesterol is up to 97%.
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Paragraph 0102-0107; 0110-0113; 0124-0126; 0128-0132; ...
(2021/11/10)
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- ORGANIC SOLVENT NANOFILTRATION OF 7-DEHYDROCHOLESTEROL OR 25-HYDROXY-7-DEHYDROCHOLESTEROL OR THEIR OH PROTECTED FORMS
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The present invention relates to the purification of 7-dehydrocholesterol or 25-hydroxy-7-dehydrocholesterol or their OH-protected forms, respectively. It has been found that the process using organic solvent nanofiltration allows an efficient reduction of the amount of a new higher molecular compound which is formed in a 5 new synthesis process of of 7-dehydrocholesterol or 25-hydroxy-7-dehydrocholes- terol or their OH-protected forms in small amounts. Said new higher molecular compound can be used as colorant.
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- New industrial method for producing vitamin D3 by taking wool fat as raw material
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The invention provides a new industrial method for producing vitamin D3 by taking wool fat as a raw material. The new industrial method comprises the following steps: carrying out saponification and primary purification on the wool fat in a low alcohol solution, thus obtaining a cholesterol crude product; directly carrying out acetylation on the cholesterol crude product, thus obtaining high-purity cholesterol acetate; then sequentially carrying out oxidizing, hydrazone forming, hydrazone removing, hydrolyzing, illuminating and the like, thus obtaining the vitamin D3. A production technology disclosed by the invention is efficient, green and environment-friendly, is high in product yield and is suitable for industrial production, and the manufacturing cost of the vitamin D3 is greatly reduced; a saponification technology is ingenious in filtrate treatment, has no generation of waste liquid and waste and is more beneficial for environment protection.
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Paragraph 0043; 0044
(2019/06/13)
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- PROCESS FOR PREPARATION OF 7-DEHYDROCHOLESTEROL
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The invention discloses an improved cost-effective process for preparation of 7-Dehydrocholesterol of formula I with good yield and purity, comprising:a) epimerizing 7(alpha+beta) bromo protected cholesterol in presence of tetrabutyl ammonium bromide in toluene or a ketonic solvent or combinations thereof to obtain predominantly 7.alpha-bromo 3-protected cholesterol; b) Reacting 7.apha-bromo 3- protected cholesterol with substituted or unsubstituted thiophenol or its salts in presence of a liquor ammonia to obtain predominantly 7β-thiophenyl)-3-protected cholesterol; c) Oxidizing 7. beta. - thiophenyl 3-protected cholesterol in presence of Cumene hydrogen peroxide and Titanium tetraisopropoxide to obtain 7. beta. -phenyl sulfoxide 3-protected cholesterol; d) Converting 7. beta. -phenyl sulfoxide 3-protected cholesterol into 7-Dehydro 3-protected cholesterol in presence of base; e) purifying 7-Dehydro 3-protected cholesterol by suspending in a suitable organic solvent; and f) Deprotecting the 7-Dehydro 3-protected cholesterol by treating with alkali in presence of methanol to obtain 7-Dehydrocholesterol followed by purification of 7-Dehydrocholesterol from an organic solvent.
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(2015/11/27)
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- Synthesis of 7-dehydrocholesterol through hexacarbonyl molybdenum catalyzed elimination reaction
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The efficiency of hexacarbonyl molybdenum catalyzed elimination reaction of the allylic acetates has been improved by the presence of O,N- bis(trimethylsilyl) acetamide in the reaction medium. The methodology is particularly well employed for the elimination of 7-acetoxycholesterol-3- acetate(cholestrol-3,7-diacetate) for which the resulting product obtained was exclusively 5,7-homoannular diene(7-dehydrocholesterol-3-acetate). Good yield is achieved (up to 70 %) while decreasing the side products formation and reducing the costs as compared to the previously used procedures. Hexacarbonyl molybdenum elimination reaction is greatly influenced by the reaction temperature, at low as well as at high temperature low yield of the homoannular diene product is separated while at moderate conditions of temperature high products formation is observed.
- Ur Rahman, Faiz,Tan, Tian Wei
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experimental part
p. 247 - 254
(2012/05/05)
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- Studies on the Constituents of Marine Opisthobranchia, III. Isolation and Structure of Two 5,8α-Epidioxysterols and a Cholesteryl Ester Mixture from the Albumen Gland of Aplysia juliana
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From the albumen glands of the sea hare Aplysia juliana, collected in Kumamoto Prefecture, a mixture of cholesteryl esters (1) and two 5,8α-epidioxysterols 5 and 8 have been isolated.Acid-catalyzed methanolysis of 1 afforded four methyl esters of fatty acids and cholesterol. 5 and 8 were identified by spectroscopic and synthetical evidence to be 5,8α-epidioxy-5α-cholest-6-en-3β-ol and 5,8α-epidioxy-5α-cholesta-6,9(11)-dien-3β-ol, respectively.
- Miyamoto, Tomofumi,Honda, Masanori,Sugiyama, Shigeo,Higuchi, Ryuichi,Komori, Tetsuya
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p. 589 - 592
(2007/10/02)
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- COVALENT MODELS FOR PHOSPHOLIPID-STEROL INTERACTIONS. SYNTHESIS OF PHOSPHATIDYL-δ5,7,9-CHOLESTATRIEN-3β-ol
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The synthesis of O-(1',2'-di-O-palmitoyl-sn-glycero-3'-phosphoryl)-Δ5,7,9-cholestatrien-3β-ol, O-(1',2'-di-O-myristoyl-sn-glycero-3'-phosphoryl)-Δ5,7,9-cholestatrien-3β-ol, and O-(1',2'-di-O-palmitoyl-sn-glycero-3'-phosphoryl)-Δ5,7-cholestadien-3β-ol, as their triethylammonium and calcium salts, is described.The "double phosphorylating" reagent, 4,5-dimethyl-2-oxo-2-chloro-1,3,2-dioxaphosphole is used to establish the phosphate bridge between the 1,2-di-O-acyl-sn-glycerol and the corresponding sterol, Δ5,7,9-cholestatrien-3β-ol or Δ5,7-cholestadien-3β-ol.The fluorescent, conjugated, polyunsaturated phosphatidylsterols are models to study noncovalent interactions between glycerophospholipids and sterols in biological membranes.
- Ramirez, Fausto,Mandal, Sukhendu B.,Marecek, James F.
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- STEREOCHEMISTRY OF THE PRODUCT OF 3β-ACETOXYCHOLESTA-5,7-DIENE HYDROXYLATION
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3β-Acetoxycholesta-5,7-diene (1) oxidized with KMnO4-NaIO4, instead of excepted diketone 2, afforded pentol monoacetate 3, which was assigned the structure of 3β-acetoxy-5α,6α,7α,8β tetrahydroxycholestane (3d) on the basis of spectral data and appropriate chemical reactions.The oxidation mechanism of 1 to 3d has been proposed.
- Rodewald, Wladyslaw J.,Boncza-Tomaszewski, Zbigniew
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p. 405 - 411
(2007/10/02)
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