- Synthesis of 16-dehydro-20-oxopregnanes from 17α,20-epoxy-23,24-dinorcholan-22-oic acids. Highly stereospecific oxirane → allyl alcohol isomerization of an epoxycarboxylic acid
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A microbial degradation product of natural sterols was converted into traditional precursor of steroid syntheses by a simple sequence. The title isomerization, the key step, was investigated to demonstrate a concerted mechanism, in which a cyclic transition state, involving the oxirane oxygen, the β- and γ-carbon, the γ-proton to be removed and the catalyst coordinated by the carboxylate group, is postulated.
- Toro, Andras,Pallagi, Istvan,Ambrus, Gabor
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- Synthesis of fluorinated 3beta-hydroxypregn-5-en-20-one derivatives.
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Treatment of the unstable 3beta-hydroxy-20, 20-dimethoxypregn-5-ene 3-acetate with acetic anhydride at reflux temperature gave a mixture of 3beta-hydroxy-20-methoxypregna-5, 17(20)-diene and 3beta-hydroxy-20-methoxypregna-5, 20-diene 3-acetates. Fluorination of this mixture with perchloryl fluoride afforded after fractionated crystallization 3beta-hydroxy-17-fluoro-20-methoxypregna-5, 20-diene 3-acetate. Acid hydrolysis of the reaction mixture and subsequent chromatographic separation led to 3beta-hydroxy-17-fluoropregn-5-en-20-one 3-acetate and 3beta-hydroxy-21-fluoropregn-5-en-20-one 3-acetate. 3beta-Hydroxy-17-fluoro-20-methoxy-pregna-5, 20-diene 3-acetate did not react further with perchloryl fluoride even under forcing conditions. Fluorination of 3beta-hydroxy-20-(N-ethyl benzylamino)-pregna-5, 17(20)-diene gave 3beta-hydroxy-17, 21-difluoro-pregn-5-en-20-one, exclusively.
- Pataki,Jensen
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- Synthesis and anti-cancer activity of chiral tetrahydropyrazolo[1,5-a]pyridine-fused steroids
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Regio- and stereoselective synthesis of novel chiral 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine–fused steroids via [8π?+?2π] cycloaddition of diazafulvenium methides with steroidal scaffolds is reported. The biological evaluation of the new family of hexacyclic steroids as anti-cancer agents was also carried out. Hexacyclic steroids bearing a benzyl group at C-22, derived from 16-dehydropregnenolone and 16-dehydroprogesterone, show considerable cytotoxicity against EL4 (murine T-lymphoma) in contrast with the corresponding C-22-unsubstituted derivatives showing low cytotoxicity. Thus, results indicate that the presence of the benzyl group is important to ensure cytotoxicity.
- Lopes, Susana M.M.,Sousa, Emanuel P.,Barreira, Luísa,Marques, Cátia,Rodrigues, Maria Jo?o,Pinho e Melo, Teresa M.V.D.
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- Steroids 48. Synthesis of 16α-ethyl-21-hydroxy-19-norpregn-4-ene-3,20-dione from 17-substituted 3-methoxyestradiols
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A new synthesis of 16α-ethyl-21-hydroxy-19-norpregn-4-ene-3,20-dione is described, starting from 17-cyano- and 17α-ethynyl-3-methoxyestra-1,3,5-(10)-trien-17-ols.Keywords: steroids; synthesis; 19-norpregnenes; A-aromatic pregnenes
- Lokoes, Magdalena,Bakos, Tamas,Vincze, Iren
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- Introduction of 20-Keto Side Chains in 17-Oxosteroids: Wittig-Horner-Emmons Reactions of (E)-17--3-methoxyandrosta-3,5-diene
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The synthesis is described of a series of polyfunctional unsaturated Δ16,20-20-isocyanosteroids 5a-f by the Wittig-Horner-Emmons reaction of (E)-17 steroid 4 with several aldehydes and with acetone.Hydrolysis of the isocyanosteroids 5a-f with dilute sulfuric acid gave Δ16-20-ketosteroids 6a-f in high yield.Hydrolysis of 5a was also possible under neutral conditions, via the intermediate Δ16,20-20-isocyanatosteroid 7a, leading to A-ring protected 16-dehydroprogesterone 8a.The Wittig-Horner-Emmons reaction, together with the described hydrolyses, provides a new method for the introduction of steroid side chains.The method is particularly suited for side chains of different size, structure, and functionality.
- Stoelwinder, Johannes,Leusen, Albert M. van
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- Preparation method of 16-dehydroprogesterone
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The invention provides a preparation method of 16-dehydroprogesterone, and belongs to the technical field of organic synthesis. The preparation method of the 16-dehydroprogesterone provided by the invention comprises the following steps: mixing 17 alpha-hydroxyprogesterone, methylbenzene, water, acetic acid and semicarbazide hydrochloride, and carrying out elimination reaction to obtain the 16-dehydroprogesterone. The method provided by the invention is low in cost, high in product yield and purity and suitable for industrial large-scale production. Specifically, 17alpha-hydroxyprogesterone is taken as a raw material, and the raw material is low in price; toluene and water are used as solvents, semicarbazide hydrochloride is used as an elimination reagent, acetic acid is used as a catalyst, a reaction system is divided into a toluene layer and a water layer, the elimination reaction is specifically carried out in the water layer, and a product generated by the reaction is extracted to the toluene layer, so that the product yield and purity are prevented from being influenced by impurities generated by excessive reaction of the product.
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Paragraph 0034-0055
(2021/06/12)
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- Sensitized Aliphatic Fluorination Directed by Terpenoidal Enones: A "visible Light" Approach
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In our continued effort to address the challenges of selective sp3 C-H fluorination on complex molecules, we report a sensitized aliphatic fluorination directed by terpenoidal enones using catalytic benzil and visible light (white LEDs). This sensitized approach is mild, simple to set up, and an economical alternative to our previous protocol based on direct excitation using UV light in a specialized apparatus. Additionally, the amenability of this protocol to photochemical flow conditions and preliminary evidence for electron-transfer processes are highlighted.
- Bume, Desta Doro,Harry, Stefan Andrew,Pitts, Cody Ross,Lectka, Thomas
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p. 1565 - 1575
(2018/02/09)
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- On a pregnane - 16 - ene - 3, 20 - dione steroid derivatives preparation method
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The invention relates to a preparation method for a pregna-16-ene-3, 20-dione steroid derivative (II). The method is characterized by: reacting 17alpha-ethynyl-17beta-hydroxysteroid derivative I with a reagent A or an organic solvent containing the reagent A to obtaining the derivative (II). The reaction temperature ranges from 25DEG C to a solvent reflux temperature, and the reagent A is a solution formed by dissolving 5%-15% of phosphorus pentoxide in methanesulfonic acid.
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Paragraph 0071; 0072
(2018/01/04)
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- New process for synthesizing steroid 3-one-4-ene
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The invention discloses a new process for synthesizing steroid 3-one-4-ene. The method comprises the steps: with steroid 3-hydroxy-5-ene as a starting material, in a nonprotic organic solvent, with air or oxygen as an oxidant and with a transition metal nitrate and a 2,2,6,6-tetramethylpiperidine-1-oxyl free radical or an analogue thereof as catalysts, oxidizing to obtain the steroid 3-one-4-ene. The method has the advantages of high yield, mild reaction conditions, easily controlled operation, low energy consumption, low cost, and safety; and the whole process is friendly to the environment, and is suitable for industrialization.
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Paragraph 0058; 0059
(2016/10/09)
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- Novel rhenium(i) catalysts for the isomerization of propargylic alcohols into α,β-unsaturated carbonyl compounds: An unprecedented recyclable catalytic system in ionic liquids
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Carbonyl rhenium(i) complexes are efficient catalysts for the regioselective isomerization of terminal propargylic alcohols into α,β-unsaturated aldehydes or ketones which can be used as an unprecedented recyclable catalytic system (up to 10 consecutive runs) in the ionic liquid [BMIM][PF6].
- Garcia-Alvarez, Joaquin,Diez, Josefina,Gimeno, Jose,Seifried, Christine M.
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supporting information; scheme or table
p. 6470 - 6472
(2011/07/09)
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- Aspects of the progesterone response in Hortaea werneckii: Steroid detoxification, protein induction and remodelling of the cell wall
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Progesterone in sublethal concentrations temporarily inhibits growth of Hortaea werneckii. This study investigates some of the compensatory mechanisms which are activated in the presence of progesterone and are most probably contributing to escape from growth inhibition. These mechanisms lead on the one hand to progesterone biotransformation/detoxification but, on the other, are suggested to increase the resistance of H. werneckii to the steroid. Biotransformation can detoxify progesterone efficiently in the early logarithmic phase, with mostly inducible steroid transforming enzymes, while progesterone biotransformation/detoxification in the late logarithmic and stationary phases of growth is not very efficient. The relative contribution of constitutive steroid transforming enzymes to progesterone biotransformation is increased in these latter phases of growth. In the presence of progesterone, activation of the cell wall integrity pathway is suggested by the overexpression of Pck2 which was detected in the stationary as well as the logarithmic phase of growth of the yeast. Progesterone treated H. werneckii cells were found to be more resistant to cell lysis than mock treated cells, indicating for the first time changes in the yeast cell wall as a result of treatment with progesterone.
- Krizancic Bombek, Lidija,Lapornik, Ajda,Ukmar, Marjeta,Matis, Maja,Cresnar, Bronislava,Katalinic, Jasna Peter,Zakelj-Mavric, Marija
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experimental part
p. 1465 - 1474
(2009/04/06)
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- Isomerization of propargylic alcohols into α,β-unsaturated carbonyl compounds catalyzed by the sixteen-electron allyl-ruthenium(II) complex [Ru(η3-2-C3H4Me)(CO)(dppf)] [SbF 6]
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The 16-e- (η3-allyl)-ruthenium(II) complex [Ru(η3-2-C3H4Me)(CO)(dppf)][SbF 6] is an efficient catalyst for the regioselective isomerization of terminal propargylic alcohols HC≡CCR1R2(OH) into α,β-unsaturated aldehydes R1R2C=CHCHO or ketones R3R4C=C(R1)COMe (if R2 = CHR3R4) under mild conditions. This complex has been also used as catalyst for the preparation of conjugated 1,3-enynes via dehydration of propargylic alcohols.
- Cadierno, Victorio,Garcia-Garrido, Sergio E.,Gimeno, Jose
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p. 101 - 110
(2007/10/03)
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- Δ16-20-Ketosteroids by C2-Elongation from Δ16-17-Substituted Steroids
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Reactions of corticoid precursor steroids with a Δ16-double bond and iodine, trimethylsilyl, tributylstannyl or trifluoromethanesulfonyloxy groups in 17-position were studied with the aim of introducing an acyl substituent in 17-position.Starting with the 17-trimethylsilyl compounds, using acyl chlorides and AlCl3 as a catalyst, a mixture of chlorinated compounds were obtained, among others.Better results gave palladium-catalyzed reactions, such as the cross-coupling of 17-tributylstannyl compounds with acyl chlorides or the substitution of the 17-iodides or the 17-triflates by vinyl ethers.In the reaction of the 17-iodides, different protecting groups are tolerated; thus this method is of general use.No Δ16-17-triflates were obtained by the reaction of androsta-4-ene-3,17-dione or androsta-1,4-diene-3,17-dione with trifluoromethanesulfonyl anhydride.This is a limitation of the triflate method, which in the other cases gives the best yields (>80percent).
- Schweder, Bernd,Uhlig, Egon,Doering, Manfred,Kosemund, Dirk
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p. 439 - 444
(2007/10/02)
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- Synthesis of 20-oxo steroids
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The synthesis is described of a series of eighteen 16-dehydro-20-isocyano-20-sulfonylpregnanes (5 and 8-14) by C-20 alkylation of 17-androstanes 1-3.The geminal isocyano and sulfonyl groups at C-20 (compounds 5, 8-14) are removed by acid hydrolysis to provide a new entry into 20-oxo steroids (6, 15-19).The C-20 alkylation also includes halomethylation and alkoxymethylation to form 21-halo- and 21-alkoxy-16-dehydro-20-oxopregnanes, respectively.As an attractive alternative to acid hydrolysis, the isocyano group is first oxidized with Pb(OAc)4 to an isocyanato group prior to hydrolysis (of the geminal isocyanato and sulfonyl groups) to the same 20-oxo steroids.The latter conversion is carried out under non-acidic conditions at room temperature in a slurry of alumina in dichloromethane.
- Leusen, Daan van,Echten, Erik van,Leusen, Albert M. van
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p. 469 - 477
(2007/10/02)
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- A NEW PROCEDURE TO Δ4-3-KETOSTEROIDS FROM 5β-3-KETOSTEROIDS
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A convenient two-step process for the conversion of 5β-3-Ketosteroid series into the corresponding Δ4-enones is described.This transformation was achieved by first forming the corresponding Δ3-enol acetate which in turn was oxidized to the enone with chromium oxidizing reagents.
- Hernandez, J. Edgardo,Samano, Vicente,Valdes, Victoria
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p. 131 - 136
(2007/10/02)
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- A Facile Synthesis of 16α-Methyl-17α,21-dihydroxy-4-pregnen-3,20-dione
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A new way of transformation of 16-dehydropregnenolone acetate (1) into 16α-methyl-17α,21-dihydroxy-4-pregnen-3,20-dione is described.
- Daniewski, Andrzej Robert,Wojciechowska, Wanda
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p. 147 - 149
(2007/10/02)
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- STEREOSPECIFIC DEOXYGENATION OF 1,2-DIOLS TO OLEFINS
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The 2-dimethylamino-1,3-dioxolane derivatives of 1,2-diols when treated with trifluoromethane sulfonic anhydride and diisopropylethylamine in toluene give the corresponding olefins stereospecifically under mild experimental conditions.
- King, John L.,Posner, Bruce A.,Mak, Kwok Tim,Yang, Nien-chu C.
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p. 3919 - 3922
(2007/10/02)
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- A NOVEL METHOD TO BUILD ACETYL AND HYDROXYACETYL SIDE-CHAINS IN 17-OXOSTEROIDS
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Nine examples are given of the title process.
- Leusen, Daan van,Leusen, Albert M. van
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p. 2581 - 2584
(2007/10/02)
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- A New Method of Transforming 11β,17α,21-Trihydroxy-20-oxo Steroids into the 21-Chloro-20-oxo-Δ9(11),16 Derivatives
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Reaction of the 17α nitrates 1a,b with lithium chloride in hexamethylphosphoric triamide or N-methylpyrrolidone results in formation of the Δ16 steroids 2a,b by elimination of the 17α nitrooxy group.The corresponding 21 mesylates 1c,d are transformed into the 21-chloro-Δ16 steroids 2b,c under the same conditions.When the reaction was carried out with the 11β,17α-dinitrooxy-21-mesyloxy derivatives 4, the 21-chloro-Δ9(11),16 steroids 5 were obtained. 5a is a suitable intermediate for a short synthesis of 10, a topical anti-inflammatory corticosteroid.
- Annen, Klaus,Hofmeister, Helmut,Laurent, Henry,Wiechert, Rudolf
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p. 966 - 972
(2007/10/02)
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- A Ready Conversion of a Pregnane-20-carboxaldehyde to 17α-Hydroxypregnan-20-ones and Pregn-16-en-20-ones
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Reaction of (20S)-5α-chloro-3β-hydroxypregnane-20-carboxaldehyde (9, prepared in two steps from stigmasterol) with oxygen and potassium tert-butoxide, followed by trimethyl phosphite treatment, afforded 5α-chloro-3β,17α-dihydroxypregnan-20-one (6) and 3β,17α-dihydroxypregn-5-en-20-one (7).This mixture was converted into 7 by potassium hydroxide treatment, and into 17α-hydroxypregn-4-ene-3,20-dione (8) by reaction with pyridinium dichromate followed by potassium hydroxide treatment.Bromination-dehydrobromination of 9, in one or two steps, afforded (Z)- and (E)-5α-chloro-3β-hydroxypregn-17(20)-ene-20-carboxaldehyde (11).Reaction of 11 with oxygen and potassium hydroxide gave 5α-chloro-3β-hydroxypregn-16-en-20-one (12), which was converted to 3β-hydroxypregna-15,6-dien-20-one (13) by further potassium hydroxide treatment, and to pregna-4,16-diene-3,20-dione (14) by Oppenauer reaction using excess aluminium isopropoxide.
- Biancini, Bruno,Caciagli, Valerio,Centini, Felice,Eletti-Bianchi, Giancarlo,Re, Luciano
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p. 1829 - 1835
(2007/10/02)
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- Process for preparing Δ9(11) and/or Δ16 -unsaturated sternoids
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A process for preparing a Δ9(11) - and/or Δ16 -unsaturated steroid comprises heating the corresponding steroid of the pregnane series substituted by 9α-chloro- and/or 16α-chloro- or 17α-acyloxy, in an inert, aprotic high-boiling solvent at 180°-350° C.
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