Synthesis of new α-chloropyridine derivatives of steroidal 3β,5α,6β-triols and 3β,5-dihydroxy-6-ketones

New steroid derivatives containing 6-chloropyridine groups characteristic of the alkaloid epibatidine and neonicotinoid insecticides were synthesized by reacting 3β,5α,6β-trihydroxysteroids or 3β,5-dihydroxy-6ketosteroids with 2-chloro-5-chloromethylpyridine. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 180-182, March-April, 2009.     

Novel Synthesis of 2β,3β,20β-Triacetoxy-5 -pregnan-6-one

Pregnenolone (2) is used in a novel synthesis of 2,3,20-triacetoxy-6-ketosteroid (6), a key intermediate in the preparation of 20-hydroxyecdysone (1)     

Synthesis of 3β,6α-dihydroxy-5α-cholan-23-one

Evidence for the presence of 3β,6α-dihydroxy-5α-chol-9(11)-en-23-one in the aglycone mixture from the starfish Marthasterias glacialis is provided by the synthesis of 3β,6α-dihydroxy-5α-cholan-23-one (19) and its identification in the hydrogenated aglycone mixture. The side-chain is constructed from the 23,24-dinorcholanol (13) by reaction of the 22-tosylate (16) with the acetylide anion, followed by hydration of the resulting 23-yne (17).     

Reaction of 3β-chloro-5α,6α-epoxysteroids with trifluoroacetic acid

It has been established that on the interaction of the 5,6-epoxysteroids (1a–c) with trifluoroacetic acid in chloroform the 6-trifluoroacetates of the 5,6-diols (2a–c) are formed in high yield. The alkaline hydrolysis of the trifluoroacetates (2a–c) leads to the corresponding diols (3a–c).Institute of Bioorganic Chemistry, Belarus' National Academy of Sciences, 220141, Belarus', Minsk, ul. Akad. Kuprevicha, 5/2. Translated from Khimiya prirodnykh Soedinenii, No. 2, pp. 201–204, March–April, 1999.     

Molecular and Crystal Structure of 2, 3, 5, 6-dipropylene-r-pyrone

11NTRODUCT1ONWeattemptedtosynthesizeanextractant(1)bythereactionofadipylchloridewithcyclopentanonepiperidineenamineaccordingtoHunig'sprocedure"',however,wemainlyobtainedthetitlecompound,whichmaybepossiblyapotentialmedicinet2'3i.Itsmolecularstructurewasfinallyconfirmedbythesingle-crystalstructuredeterminationafterconventionalUV,IR,lHNMR,MSandelementana-lyticalworks.2EXPER1MENTALSECT1ON2.1SynthesisToastirredsolutioncontaining8Omlofchloroform,2.8mloftri-ethylamineand1.51g(O-Olmol)…     

Oxidation of Steroidal 5-En-3β-ol with Pyridinium Chlorochromate: Isolation of Key Intermediate,Steroidal 6β-Hydroxy-4-en-3-one

The PCC oxidation of 5-en-3β-ol steroids proceeds to 4-en-3,6-dione through the intermediate 5-en-3-one. The isolation of another key intermediate, steroidal 6β-hydroxy-4-en-3-one guides an understanding of the mechanism involved.     

Isolation and Crystal Structure of Stigmast-4-ene-3β,6β-diol

The title compound (C29H50O2, Mr = 430.69) was isolated from the algae Halimeda xishaensis collected from the South China Sea. Its crystal structure was determined by single-crystal X-ray diffraction for the first time. The crystal belongs to orthorhombic, space group P212121 with a = 8.1560(13), b = 10.7861 (18), c = 29.973(5) A, V = 2636.8(8)A3, Z = 4, Dc = 1.085 g/cm3, F(000)= 960, μ(Mo-Ka) = 4.533 mm-1, λ = 0.71073 A, S = 1.061, (△ρ)max= 0.382 and (△ρ)min= -0.244e/A3. The structure was refined to R = 0.0561 and wR = O. 1553 for 2711 observed reflections with I ＞ 2σ(I). X-ray diffraction analysis reveals that the title compound has two β-OH groups, and the side chain is saturated. There exist two intermolecular hydrogen bonds between three molecules.     

Reaction of 5β,6β-epoxy-16α,17α-cyclohexapregnane with methylmagnesium iodide

On treatment with methylmagnesium iodide, 3β-acetoxy-5β,6β-epoxy-16α,17α-cyclo-hexapregnan-20-one undergoes 3-O-deacetylation along with the opening of the 5β,6β-epoxide ring to form 5α-methyl-6β-hydroxy steroid and the 6α-methyl-6β-hydroxy isomer, the 20-keto group remaining intact.     

Synthesis of Stigmastane 5β-Hydroxy-6-ketosteroids

-Sitosterol 1 and the intermediate 5-hydroxy-6-ketosteroids 2 and 3 were used to synthesize 5-hydroxy-6-ketosteroid oximes 4 and 5. Dehydration of 5 fromCinachyrellasponges forms (24R,6E)-24-ethylcholest-6-hydroximino-4-en-3-one 6, a steroidal oxime     

Reaction of Pregnenolone and 3α,5-Cyclo-5α-pregnan-6β-ol-20-one with Trifluoroperacetic Acid

The reaction of pregnenolone and 3,5-cyclo-5-pregnan-6-ol-20-one with trifluoroperacetic acid produces the trifluoroacetates, hydrolysis of which gives the 3,5alpha;,6-triol.     

Studies on stereocontrolled epoxidations of bis-alicyclic alcohols in steroidal skeletons: preparation of eight diastereomerically pure epoxides from cholest-4-en-3β,6β-; -3β,6α-; -3α,6β- and -3α,6α-diols

Eight diastereomerically pure epoxides have been prepared from cholest-4-en-3β,6β; -3β,6α-; -3α,6β- and -3α,6α-diols via a combination of steric, protecting group and oxidant effects on stereocontrolled epoxidations of a bis-alicyclic alcohol system within the steroidal skeleton.     

Synthesis and transformations of 2β,3β-diacetoxy-20-(4,5-dihydroisoxazol-5-yl)-6-oxo steroids

20-Hydroxy-20-(4,5-dihydroisoxazol-5-yl) steroid was brought into reactions typical of functionalization of rings A and B in ecdysteroids. The dihydroisoxazole ring remained unchanged in reactions leading to formation of the 2,3-dihydroxy-6-oxo moiety. The isomerization of 5-bromo derivative in acetic acid in the presence of a catalytic amount of hydrobromic acid and Lewis acids is accompanied by elimination of the hydroxy group from C²⁰ and subsequent migration of the double bond to the heteroring to afford the corresponding isoxazole derivative.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1500–1505.Original Russian Text Copyright © 2004 by Litvinovskaya, Drach, Khripach.     

Synthesis of 24-Methylene-cholest-5-ene-7-oxo-3β,19-diacetate

24-Methylenecholest-5-ene-7-oxo-3β,19-diacetate 5 was synthesized starting from stigmasterol via twelve step reactions in 4.1% overall yield. It can be served as a key intermediate for the synthesis of 24-methylenecholest-5-ene-3β,7β,19-mol 1, a naturally occuring polyhydroxylated sterol with potential biological activity.     

Synthesis of 2β, 3β, 14α-trihydroxy-Δ4,7-6-ketosteroids and their derivatives

A scheme using -sitosterol as an example for synthesizing 2, 3, 14-trihydroxy-^4,7-6-ketosteroids and their derivatives from 3-hydroxy-⁵-steroids was developed.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141, Belarus, Minsk, ul, akad. Kuprevicha, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 244–248, May–June, 2000.     

Synthesis of (24R)-3β,5,14α-trihydroxy-5α-stigmast-7-en-6-one 3-benzoate

An ecdysteroid analog has been synthesized from -sitosterol.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus', 220141, Belarus', Minsk, ul. Akad. Kuprevich, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 488–491, July–August, 1999.     

Three steroids with unique structural feature of 5β-Spirostan-1β,3β,17α-trihydroxyl from Reineckia carnea

A new spirostanol sapogenin and two spirostanol saponins, tentatively named reineckiagenin A (1), reineckiagenoside A (2), and reineckiagenoside B (3), were isolated from the whole plant of Reineckia carnea. By detailed analysis of their 1D and 2D NMR spectra, chemical methods, and by comparison with spectra data of known compounds, the structures of the new steroids were determined to be 25(S)-5β-spirostan-1β,3β,17α-triol (1), 25(S)-5β-spirostan-1β,3β,17α-triol 1-O-β-D-xylopyranoside (2), 25(S)-5β-spirostan-1β,3β,17α-triol 1-O-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranoside (3). Compounds 1, 2, and 3 are the first naturally occurring steroids with unique structural feature of 5β-spirostan-1β,3β,17α-trihydroxyl.     

Synthesis of Novel 17α-Eethynyl-5-androstene-3β, 7β, 17β-triol (HE3286)Derivatives

以脱氢表雄酮为原料,经羟基乙酰化,羰基亚乙二氧基化,CrO3/3,5-二甲基吡啶氧化,硼氢化钠还原,脱17-位亚乙二氧基,脱3-位乙酰基,用叔丁基二甲基氯硅烷(TBDMSC1)保护3,7-OH,17-位环氧化,17-位开环,脱TBDMSC1保护等十步反应合成了四个新型的17α-乙炔基-5-雄甾烯-3β,7β,17β-三醇(HE3286)衍生物,其结构经1H NMR和MS表征.