Synthesis of 6-chloronicotinates of steroidal 3β,5α,6β-triols and 3β,5-dihydroxy-6-ketones

New esters of 3β,5α,6β-trihydroxysteroids and 3β,5-dihydroxy-6-ketosteroids containing 6-chloropyridine groups characteristic of the alkaloid epibatidine were synthesized by acylation with 6-chloronicotinoylchloride. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 175-179, March-April, 2009.     

First Total Synthesis of 3α,4α-Oxidoagarofuran and (-)-3β,4α-Dihydroxy-β-dihydroagarofuran

The first stereoselective total synthesis of (–)-3β, 4α-dihydroxy-β-dihydroagarofuran (1) and 3α, 4α-oxidoagarofuran (2) has been described. The key step is the epoxidation of α-agarofuran (6) with dimethyldioxirane.     

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.     

A new resolution of (1α,2β,3α,4β)-2,3-dibromocyclohex-5-en-1,4-diol by lipase from Mucor miehei

An efficient resolution of 2,3-dibromocyclohex-5-en-1,4-diol has been carried out, using Mucor miehei lipase operating in an organic solvent. The enantioforms obtained may find application in the preparation of chiral conduritols.     

The First Total Synthesis of Natural 6β-Cinnamoyloxy-1α- hydroxy-5, 10-bis-epi-eudesm-4-en-3-one

Eudesmane and agarofuran are naturally occurring sesquiterpenoids with characteristic decalin skeletons. These natural products frequently contain multiple hydroxyl groups and contiguous stereocenters. Members from these families show cytotoxic, immuno- s…     

Singlet oxygen addition to chiral allylic alcohols and subsequent peroxyacetalization with β-naphthaldehyde: synthesis of diastereomerically pure 3-β-naphthyl-substituted 1,2,4-trioxanes

The synthesis of a series of eight β-naphthyl-substituted 1,2,4-trioxanes 3a-h by a sequence of singlet oxygen ene reaction of allylic alcohols 1a-h and Lewis acid catalyzed peroxyacetalization of the allylic hydroperoxides 2a-h with β-naphthaldehyde is reported. The ene reactions were performed by solid-state photooxygenation in dye-crosslinked polystyrene beads and resulted in mixtures of diastereoisomeric hydroperoxides 2. Boron trifluoride catalyzed peroxyacetalization resulted in the formation of 3, as well as the 1,2,4-trioxanes 4 and 5, which were formed via acid catalyzed β-hydroperoxy alcohol cleavage.     

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.     

A Facile Synthesis of 6β-Hydroxy-7α(H)-eudesma-4-en-3-one

Sesquiterpenesconstituteagroupofnaturalcompoundswhichexhibitconsiderablebiologicalactivities,suchasantiinflamatoryicytyotoxic'andcytotoxic',seedgendnation'andmolluscacidalactivities4.InrecentyearsanumberofC-6oxyfunctionalizedeudesmanesand6-dihydroagarofurans,suchascomPounds3-6',havebeenisolatedfromnaturesources.HoweverthereportSonthesynthesisofthisparticularkindofcompoundsarefewandthereportedsynthesesaregenerallybysyntheticmethodologystartingfroma-santonin2e.Ourinterestofstudyonthesynthesisof…     

A MULTIGRAM PREPARATIVE SYNTHESIS OF CHOLEST-4-EN-3α,6β- AND -3α,6α-DIOLS

A preparative synthesis of cholest-4-en-3α,6β- and -3α,6α-diols 10 and 15 using cheap reagents and simple working-up procedures without chromatography on a multigram scale is described.     

Efficient preparation of enantiomerically pure (E)-γ-hydroxy-α,β-unsaturated p-tolylsulfoxides using lipase-mediated acylations

(E)-γ-Hydroxy-α,β-unsaturated p-tolylsulfoxides 1 have been efficiently resolved via irreversible enzymatic acylation with lipase PS (Pseudonomas cepacia) and vinyl acetate.     

Studies on Mechanism of Chemiluminescence Reaction of 2, 6, 7-Trihydroxyl-9-(4'-chlorophenyl )-3-fluorone

1INTRoDUCTIONPhenylfluoroneisanimportanttypeofreagentinanalytica1chemistry"~'>.Themoleculesofthisreagenthavearigidplanarstructuret5'6i,sotheenergyofmolecularorbitsofthereagentscanbecalculatedbyHuckelmolecularorbitalmethod(HMO).WehadtriedtoassigndissociationconstantsforsomesuchreagentsbyacombinedspectrophotometricandHMOmethodt7'8i.Them.thodissimpleandtheresultsaresatisfactory.Inthispaper,apossiblemechanismforcatalyticchemiluminescencere-actionofCl-PFisproposedonthebasisofstudyingchemil…     

Synthesis of Hydroxylated Sterols(Ⅱ)--Synthesis of 24-Methylenecholest-4-en-3β,6α-diol

In our study on the soft coral,Alcyonium patagonicum,a new hydroxylated sterol,24-methylenecholest-4-en-3β,6α-diol(1) exhibiting a potent activity to murine leukemia cells(IC50=1 μg/mL) has been isolated[1] and synthesized[2,3].As a part of our studies on the relationship between the chemical structure and the biological activity of the hydroxylated sterols,the synthesis of 24-methylenecholest-4-en-3β,6α-diol(2) is reported here.     

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.     

Facile Synthesis of 6β-Hydroxy-7α(H)-eudesma-4-en-3-one and β-Cyperone

Eudesmane derivatives have been drawing considerable attention due to their wide spectrum of biological proerties, particulaly antifeedant, cell growth inhibitory and plant growth regulating activities.¹ In recent years a number of C-6 oxyfunctionalized eudesmanes and β-dihydroagarofurans,such as compounds 3-6,have been isolated from nature sources. However the reports on the synthesis of this particular kind of compounds are few and the reported syntheses are generally by synthetic methodology starting from α-santonin 2². Our interest of study on the synthesis of this kind of compounds prompted us to investigate a new synthetic route from cheap material (+)-dihydrocarvone 7.     

Preliminary Studies on Acylation of 10β-OH and 7α-OH in 7-Epi-10-deacetylpaclitaxel

Paclitaxel(=Taxol@Xl)hasbeensuccessfullyaPpliedtometaStaicovaryandbreaStcancertheraPyt'l.ThecomplexityofchemicalStructUreandreactivitiesofthisPOlyoxygenatedmoleculedreWalotofattentionfromorganicchemists.ThesecondaryhydroxylsattahedtoC-2,7,lOandl3eXhibitedvariousreaCtivitiesindifferentbaccatinIIl(2)analogsl'l.Generally,76-OHismorereactivetowardselectrophilicreagentSthanlOP-OHl'l.Thispropertyisutilhableinthepreparaionof7-TES-baccatinIlI(3),anAnportantintermediateforthesemisynthesisof…     

Reactivity of Hydroxy and Keto Groups on C-6 and C-17 of 3α,5α-Cycloandrostanes

Convenient methods for preparing several 3,5-cycloandrostanes have been developed in order to synthesize the phytoecdysteroid rubrosterone. Certain of their chemical transformations were studied     

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.     

Possible conformations of the seven-membered rings and relative stabilities of 1β,5α,6β,7α(H)- and 1α,5α,6β,7α(H)-guai-11(13)-en-6,12-olides

A calculation has been made by the method of molecular mechanics, using the MM2 program, of a number of stereomeres of 1,5,6,7(H)- and 1,5,6,7(H)-guai-11(13)-en-6,12-olides. The possibilities of the adoption by the seven-membered ring of particular conformations according to the type of its linkage with the 5-membered carbocycle have been considered. Questions of the influence of the orientation of the Me groups on the degree of distortion of the conformation of the seven-membered ring from the ideal and the relative stabilities of the various conformers are discussed.A. N. Nesmeyanov Institute of Organometallic Compounds, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 198–203, March–April, 1991.     

Studies on ZnBr2-mediated synthesis of axially chiral aryl-substituted allenes from terminal alkynes,aromatic aldehydes and (S)-α,α-diphenylprolinol

The studies on the ZnBr₂-mediated synthesis of axially chiral aryl-substituted allenes from terminal alkynes, aromatic aldehydes, and commercially available chiral amine (S)-α,α-diphenylprolinol were conducted. Axially chiral aryl-substituted allenes can be obtained in moderate yields with up to 96% ee.