- Unified Total Synthesis of Five Bufadienolides
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We report a unified total synthesis of five bufadienolides: bufalin (1), bufogenin B (2), bufotalin (3), vulgarobufotoxin (4), and 3-(N-succinyl argininyl) bufotalin (5). After the steroidal ABCD ring 8 was produced, the D ring was cross-coupled with a 2-pyrone moiety and stereoselectively epoxidized to generate 6. TMSOTf promoted a stereospecific 1,2-hydride shift from 6 to establish the β-oriented 2-pyrone of 19. Functional group manipulations from 19 furnished 1-5, which potently inhibited cancer cell growth.
- Hagiwara, Koichi,Inoue, Masayuki,Itoh, Hiroaki,Shimizu, Shinsuke
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- Catalytic removal of tert-butyldimethylsilyl (TBS) ether by PVP-I
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A mild, efficient and rapid protocol the deprotection of alcoholic TBDMS ethers using PVP-1 as catalyst in methanol, the procedure of deprotection of various TBDMS ethers were found to be very convenient, easy work-up, high yielding.
- Ke, Yanxiong,Lu, Guangying,Ren, Jiangmeng,Wang, Di,Zeng, Bu-Bing
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- Stereo selective one-step reduction in the steroid skeleton 4 - ene -3 - ketone as a 3 α - hydroxy - 5 β - hydrogen A/B cis structure method
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The invention relates to a method for one-step reduction of a 4-ene-3-one structure in a steroid skeleton into an A/B cis-3a-hydroxy-5b-hydrogen structure, belonging to the fields of organic chemistry and drug synthesis. According to the method, under the conditions of room temperature and an environment of absolute ethyl alcohol, cuprous chloride is used as a catalyst and sodium borohydride is used as a reducing agent for high-selectivity conversion of the 4-ene-3-one structure of 4-AD, ADD and derivatives thereof into the A/B cis-3a-hydroxy-5b-hydrogen structure. According to results of X-diffraction results, an androstane-3a-hydroxy-5b-hydrogen-17-one product prepared by using the method has a stereo structure; reaction conditions are mild and simple; used reagents are cheap and easily available; operation is convenient; good repeatability is realized, and high yield is obtained. The method provided by the invention lays a good foundation for exploitation of resourceful utilization of sterol and for research on synthesis of drugs like ursodesoxycholic acid, chenodeoxycholic acid, deoxycholic acid and ecdyson with the A/B cis-structure with non-cholic acid type steroids as raw materials.
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Paragraph 0022; 0041; 0042; 0043
(2017/02/17)
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- Characterization of rabbit aldose reductase-like protein with 3β-hydroxysteroid dehydrogenase activity
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In this study, we isolated the cDNA for a rabbit aldose reductase-like protein that shared an 86% sequence identity to human aldo-keto reductase (AKR)1 1B10 and has been assigned as AKR1B19 in the AKR superfamily. The purified recombinant AKR1B19 was similar to AKR1B10 and rabbit aldose reductase (AKR1B2) in the substrate specificity for various aldehydes and α-dicarbonyl compounds. In contrast to AKR1B10 and AKR1B2, AKR1B19 efficiently reduced 3-keto-5α/β-dihydro-C19/C21/C24-steroids into the corresponding 3β-hydroxysteroids, showing Km of 1.3-9.1 μM and kcat of 1.1-7.6 min-1. The stereospecific reduction was also observed in the metabolism of 5α- and 5β- dihydrotestosterones in AKR1B19-overexpressing cells. The mRNA for AKR1B19 was ubiquitously expressed in rabbit tissues, and the enzyme was co-purified with 3β-hydroxysteroid dehydrogenase activity from the lung. Thus, AKR1B19 may function as a 3-ketoreductase, as well as a defense system against cytotoxic carbonyl compounds in rabbit tissues. The molecular determinants for the unique 3-ketoreductase activity were investigated by replacement of Phe303 and Met304 in AKR1B19 with Gln and Ser, respectively, in AKR1B10. Single and double mutations (F303Q, M304S and F303Q/M304S) significantly impaired this activity, suggesting the two residues play critical roles in recognition of the steroidal substrate.
- Endo, Satoshi,Matsunaga, Toshiyuki,Kumada, Sho,Fujimoto, Airi,Hara, Akira,Ohno, Satoshi,El-Kabbani, Ossama,Hu, Dawei,Toyooka, Naoki,Mano, Jun'Ichi,Tajima, Kazuo
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p. 23 - 30,8
(2020/08/20)
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- Phosphine effects in the copper(I) hydride-catalyzed hydrogenation of ketones and regioselective 1,2-reduction of α,β-unsaturated ketones and aldehydes. Hydrogenation of decalin and steroidal ketones and enones
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The stereoselectivity and regioselectivity of the catalytic hydrogenation of ketones and α,β-unsaturated ketones and aldehydes using soluble copper(I) hydride catalysts have been investigated as a function of the ancillary phosphine ligand. While a relatively narrow range of aryldialkylphosphine ligands produce active hydrogenation catalysts, some ligands provide higher selectivity for 1,2-reduction of acyclic unsaturated carbonyl substrates than observed using the previously reported dimethylphenylphosphine-stabilized catalyst. The synthetic utility of this class of hydridic hydrogenation catalysts is illustrated by the hydrogenation of decalin and steroidal ketones and enones, the latter giving allylic alcohols with high selectivity. (C) 2000 Elsevier Science Ltd.
- Chen, Jian-Xin,Daeuble, John F.,Stryker, Jeffrey M.
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p. 2789 - 2798
(2007/10/03)
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- Heterogeneous Catalysis in Carbonyl Regeneration from 1,3-Dithiolanes and 1,3-Dithianes by Zirconium Sulfophenyl Phosphonate
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Layered zirconium sulfophenyl phosphonate was found to be an efficient heterogeneous catalyst for mild hydrolysis of 1,2 dithiolanes and 1,3 dithianes to their corresponding carbonyl compounds.
- Curini, Massimo,Marcotullio, Maria Carla,Pisani, Emanuela,Rosati, Ornelio,Costantino, Umberto
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p. 769 - 770
(2007/10/03)
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- Reductive dehalogenation of α-haloketones promoted by hydroiodic acid and without solvent
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Several α-haloketones have been transformed into the corresponding ketones by reaction with aqueous 57% HI, without solvent. The products are obtained in nearly quantitative yields and with high purity (>99%) even in the case of sterically hindered starting materials.
- Penso,Mottadelli,Albanese
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p. 1385 - 1391
(2007/10/02)
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- 16-substituted androstanes and 16-substituted androstenes
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Compounds of the formula: STR1 are useful as anti-cancer, anti-obesity, anti-diabetic, anti-coronary agents, anti-aging agents, anti-hypolipidemic agents and anti-autoimmune agents.
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- Homoandrostan-17-one and homoandrosten-17-ones
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Compounds of the formula: STR1 useful as anti-cancer agents, anti-obesity agents, anti-hyperglycemic agents, anti-aging agents, anti-hyperglycemic agents and anti-autoimmune agents.
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- A New Procedure for Dethioacetalization via Equilibrium Exchange with Aqueous Acetone, Paraformaldehyde and Amberlyst 15 as Acidic Catalyst
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Carbonyl compounds were regenerated from corresponding Ethanediyl S,S-Acetals via equilibrium exchange with aqueous acetone, paraformaldehyde and Amberlyst 15, as acidic catalyst, at 80 deg C.
- Ballini, Roberto,Petrini, Marino
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p. 336 - 337
(2007/10/02)
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- 17-Hydroxy-steroids
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Compounds of the formulae: STR1 are useful as anti-cancer, anti-obesity, anti-diabetic, anti-coronary agents, anti-aging agents, anti-hypolipidemic agents and anti-autoimmune agents.
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- REGIOSELECTIVE REDUCTION OF POLYKETONES ON SILICA GEL SURFACE WITH BORANE-TRIMETHYLAMINE COMPLEX
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Steroidal diones and trione, bicyclic diones (7 and 8) and a tricyclic dione were adsorbed on silica gel and reduced with BH3*NMe3.The carbonyl groups at C-3 of the steroids, at C-4 of 7 and at C-3 of 8 were reduced regioselectively.The FT-IR spectra of 5α- and 5β-androstane-3,17-dione adsorbed on silica gel were measured.
- Gohzu, Shun-ichi,Tada, Masahiro
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- CHEMOSELECTIVITY IN MOLYBDENUM CATALYZED ALCOHOL AND ALDEHYDE OXIDATIONS
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Hydrogen peroxide in the presence of (NH4)6Mo7O24*4H2O and potassium carbonate is a chemoselective method to oxidize secondary alcohols to ketones and to oxidize aldehydes to acids, the latter also accelerated by cerium chloride.
- Trost, Barry M.,Masuyama, Yoshiro
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p. 173 - 176
(2007/10/02)
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- Microbial Oxidation of Sterol Side-Chains
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Several sterol metabolising microorganisms, Pseudomonas convexa, P. stutzeri, Micrococcus sp., Cephalosporium longisporum and Moraxella sp. were isolated from soil on 2-cyclopentyl-6-methyl heptane and cholestane as carbon sources.All these organisms were shown to have the capacity of oxidizing the eight carbon side chain of cholesterol.Excepting P. convexa, the organisms needed a chelating agent for prevention of steroid ring degradation.The Moraxella sp. proved to be the most versatile as it degraded cholesterol derivatives such as 3β-methoxy cholest-5-ene, 3β-chloro cholest-5-ene, 3,5-cyclocholestan-6-one and potassium cholesteryl sulphate to the corresponding 17-keto steroids in 10-50percent yield in shake flasks.It also gave high yields of estrone from both 19-hydroxy-3β-acetoxy cholest-5-ene and 19-hydroxy-3β-acetoxy sitost-5-ene.Two new enzymes one carrying out the oxidative O-demethylation of 6β-methoxy 3,5-cyclocholestane and the other, the isomerisation of i-steroids to normal 3β-hydroxy-Δ5 steroids were discovered.Immobilized Moraxella cells in agar carried out the side chain degradation of cholesteryl sulphate to yield 3β-hydroxy androst-5-en-17-one sulphate and the 19-hydroxy-3β-acetoxy derivatives of both cholesterol and sitosterol to estrone in high yields.The half life of entrapped cells was estimated to be 28 days.
- Bhattacharyya, P. K.,Rao, M. Krishna,Natarajan, Rama Devi,Ramgopal, Malathi,Madyastha, Prema,Madyastha, K. M.
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- Stereoselective and Regioselective Reduction of Steroid Ketones by Potassium Tri(R,S)-s-butyl)borohydride
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Potassium tri(R,S-s-butyl)borohydride reduces 3-oxo-steroids of the 5α- and 5β-series to the axial alcohol under conditions in which the 17- and 20-ketone groups remain unaffected.
- Goendoes, Gyoergy,Orr, James C.
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p. 1239 - 1240
(2007/10/02)
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- Process for the preparation of 17β-hydroxy-3-oxo-17α-pregn-4-ene-21-carboxylic acid γ-lactone
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A new process utilizing certain novel intermediates for the preparation of 17β-hydroxy-3-oxo-17α-pregn-4-ene-21-carboxylic acid γ-lactone is described herein. The procedure utilizes readily available and inexpensive sarsasaponin as starting material.
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- Synthesis of new steroid haptens for radioimmunoassay. III. 15beta Carboxyethylmercaptosteroid bovine serum albumin conjugates. Specific antisera for radioimmunoassay.
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The synthesis of 15β carboxyethylmercapto 5α dihydrotestosterone, 15β carboxyethylmercapto 5α androstane 3β, 17β diol and 15β carboxyethylmercapto 5α androstane 3α, 17β diol and the preparation of their bovine serum albumin (BSA) conjugates are described.
- Rao,Khan,Moore Jr.
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p. 171 - 184
(2007/10/10)
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