633-34-1Relevant academic research and scientific papers
Platinum-Catalyzed α,β-Desaturation of Cyclic Ketones through Direct Metal–Enolate Formation
Chen, Ming,Dong, Guangbin
supporting information, p. 7956 - 7961 (2021/03/01)
The development of a platinum-catalyzed desaturation of cyclic ketones to their conjugated α,β-unsaturated counterparts is reported in this full article. A unique diene-platinum complex was identified to be an efficient catalyst, which enables direct metal-enolate formation. The reaction operates under mild conditions without using strong bases or acids. Good to excellent yields can be achieved for diverse and complex scaffolds. A wide range of functional groups, including those sensitive to acids, bases/nucleophiles, or palladium species, are tolerated, which represents a distinct feature from other known desaturation methods. Mechanistically, this platinum catalysis exhibits a fast and reversible α-deprotonation followed by a rate-determining β-hydrogen elimination process, which is different from the prior Pd-catalyzed desaturation method. Promising preliminary enantioselective desaturation using a chiral-diene-platinum complex has also been obtained.
A practical Δ1-dehydrogenation of Δ4-3-keto-steroids with DDQ in the presence of TBDMSCl at room temperature
Chen, Kaixiong,Liu, Chang,Deng, Le,Xu, Guangyu
experimental part, p. 513 - 516 (2010/06/21)
A mild and efficient Δ1-dehydrogenation of Δ4-3-keto-steroids with DDQ in the presence of tertbutyldimethylchlorosilane at room temperature was developed.
Reactions of Enolizable Steroidal 4-En-3-ones and 17-Ones with Hypervalent Iodine
Numazawa, Mitsuteru,Mutsumi, Ayako,Ogata, Mieko
, p. 3381 - 3386 (2007/10/02)
Reaction of the 3-oxo-4-androsten-derivative 1 or 4 with 1.2 eq. of o-iodosylbenzoic acid in methanolic KOH gave the methoxy products, the 4-methoxide 2 or 5 and the 6β-methoxide 3 or 6, along with dehydrated compound, the 4,6-dienone 7 or 8, respectively.Treatment of the 6-methoxide 3 or 6 with trimethylsilyl iodide yielded the 5α-androstane-3,6-dioxo derivative 11 or 12 in high yield.The same hypervalent oxidation of the 17-oxo steroid 15, 18, 21 or 24 using excess iodine and a longer reaction time produced the corresponding 16α-hydroxy-17,17-dimethylacetal 16, 19,22 or 25, which was converted into the 16α-hydroxy-17-one 17, 20, 23 or 26 by treatment with diluted HCl in every case.Keywords - hypervalent iodine oxidation; o-iodosylbenzoic acid; 4-en-3-oxo steroid; 17-oxo steroid; methoxylation; dehydration; 16α-hydroxy-17,17-dimethoxy steroid; 16α-hydroxy-17-oxo steroid; 5α-saturated 3,6-dioxo steroid
Methoxylation of Enolizable Steroidal 4-Ene-3-ones using Hypervalent Iodine
Numazawa, Mitsuteru,Ogata, Mieko
, p. 1092 - 1093 (2007/10/02)
Reaction of androst-4-ene-3,17-dione (1) with o-iodosylbenzoic acid in methanolic potassium hydroxide gave the methoxylated products, the 4- and 6β-methoxides (2) and (3), along with the dehydrogenated compound, the 4,6-dienone (4).
CHROMIUM(VI) BASED OXIDANTS-1. CHROMIUM PEROXIDE COMPLEXES AS VERSATILE, MILD, AND EFFICIENT OXIDANTS IN ORGANIC SYNTHESIS.
Firouzabadi, H.,Iranpoor, N.,Kiaeezadeh, F.,Toofan, J.
, p. 719 - 726 (2007/10/02)
The preparation of 2,2'-bipyridylchromium peroxide, pyridinechromium peroxide, and chromium peroxide etherate is described. 2,2'-Bipyridylchromium peroxide converts different classes of alcohols to the carbonyl compounds.In 1,2-diols C-C bond cleavage occurs extensively. α-Hydroxy acids are decarboxylated quantitatively.Oximes are converted to their carbonyl compounds and thiols to their disulfides, dihydroxy phenolic compounds to quinones, benzyl amine to benzaldehyde, aromatic amines to their azo compounds, anthracene and phenanthrene to their quinones.Pyridinechromium peroxide converts different classes of alcohols efficiently to the carbonyl compounds, thiols to their disulfides, anthracene to anthraquinone.Mandelic and benzilic acids are decarboxylated very efficiently.Chromium peroxide etherate is an efficient reagent for the oxidation of different classes of alcohols to their carbonyl compounds.
4-Chloromercurioandrosta-4,6-diene-3,17-dione: Preparation, X-Ray Structure Determination, and Potential Utility
Drew, Michael G. B.,Mann, John,Pietrzak, Barbara
, p. 1049 - 1054 (2007/10/02)
The novel steroid 4-chloromercurioandrosta-4,6-diene-3,17-dione (2) was obtained as a major side-product during conversions of 6β-bromoandrost-4-ene-3,17-dione (1b) into its 6β-fluoro derivative (1a) using HF(pyridine)n and mercuric oxide.Compound (2) was successfully converted into various 4-substituted steroids (using standard vinyl-mercury methodology), including the disteroidal mercury compound (3c).Crystals of the acetone solvate of (2), 2(HgClC19H40O2)*acetone, were monoclinic, space group P21, Z=2 with dimensions a=7.295(8), b=24.12(1), c=12.215(12) Angstroem, β=108.0(1) deg.The two independent molecules have equivalent structures with the mercury atoms strongly bound to a chlorine atom and to carbon atom C(4) of the steroid.The acetone molecule forms a weak bridge between the two mercury atoms.
Microbiological Transformations. Part 3. The Oxidation of Androstene Derivatives with the Fungus Cunninghamella elegans
Crabb, Trevor A.,Dawson, Philip J.,Williams, Roger O.
, p. 2535 - 2541 (2007/10/02)
The products obtained from the incubation of some Δ4- and Δ5-androstene derivatives with Cunninghamella elegans are largely those arising from allylic oxidation or epoxidation of the double bond, but some 9-, 12-, 14-, and 16-hydroxylation also occurs.
A synthesis of 7alpha-hydroxyandrost-4-ene-3,17-dione.
Hossain,Kirk,Mitra
, p. 603 - 608,605, 607 (2007/10/12)
The first convenient chemical synthesis of 7alpha-hydroxyandrost-4-ene-3,17-dione is reported. Androsta-4,6-diene3, 17-dione was converted into its 6alpha, 7alpha-epoxy-derivative; reduction of the epoxide with aluminum amalgam gave 7alpha-hydroxyandrost-4-ene-3,17-dione. This reducing agent is more efficient than chromous acetate for the purpose.
3-Keto-7 α,β-loweralkyl-Δ 5-steroids
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, (2013/12/16)
7(α,β)-Loweralkyl-3-keto-Δ 5 -androstanes and 7(α,β)-loweralkyl-3-keto-Δ 5 -pregnanes having anabolic, androgenic, claudogenic, progestational and anti-progestational properties are prepared by reacting 3-keto-4,6-dienic androstanes and pregnanes with organocopper reagents such as dialkyllithium cuprate. The isomerization of these compounds to yield 7(α,β)-loweralkyl-3-keto-Δ 4 -steroids is also described.
