5α-还原酶抑制剂

5α-还原酶抑制剂是一类重要的治疗良性前列腺增生、男性秃顶、女性多毛等症状的药物。本文从甾体化合物和非甾体化合物两方面介绍了5α-还原酶抑制剂的研究进展。     

Biomimetic synthesis of 5α-hydroxy-guaianolides

A 5α-hydroxy-guaianolide was synthesized biomimetically from a 5-oxo-E-1(10)-germacrenolide, the stereoselectivity of the cyclization being attributed to preferred conformation.     

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).     

Synthesis of 5α-Iodo-6-one Steroids

Abstract: The synthesis of 5-iodo-5α-cholestan-6-one (6), its 3β-acetoxy-(7) and 3β-chloro-(8) analogues, 3β-acetoxy-5-iodo-5α-stigmastan-6-one (9) and its 3β-chloro-(10) analogue by the reacion of silver chromate-iodine and pyridine with the corresponding steroidal olefins (1-5) is described. The structures of these products have been established on the basis of their elemental, analytical and spectral data.     

First Total Synthesis of 5_α-Hydroxy-isopterocarpolone

Sesquiterpenic compounds of the Eudesmane family have attracted considerable attention due to their intriguing biological properties1,2, particularly significant antifeedant activity, cell growth inhibitory and plant growth regulating activities.In 1996, J. Hu and co-workers3 had isolated eudesmane sesquiterpene 5?-hydroxy-isopterocarpolone 1 from the aerial parts of chinese folk medicine Artemisia eriopoda and elucidated its structure by spectropic methods. Herein, we reported the first tota…     

STEREOCHEMISTRY OF THE BENZILIC ACID-TYPE REARRANGEMENT IN BASE-CATALYZED AUTOXIDATION OF 3α,5-CYCLO-5α-CHOLESTANE-6-ONE

The configuration of the hydroxy acid 2, a product from base-catalyzedautoxidation of 3α,5-cyclo-5α-cholestane-6-one,was established on the basis of NMRtechniques and the mechanism of the formation of 2 was discussed.     

Synthesis ofα-substitutedα-amino acids by the alkylation of 5-oxazolinone derivatives

Methods have been developed for the alkylation of 5-oxazolinone derivatives in DMF in the presence of K₂CO₃, KOH, or diisopropylethylamine and a phase transfer catalyst as well as for the preparation of-methyl-phenylalanine,-methylalanine,-methylalanine, and the methyl ester of N-benzoyl--methylalanine. Increasing the initial concentration of the starting 5-oxazolinone in the reaction mixture leads to a sharp drop in the yield of reaction products due to side condensation reactions. The reaction of 2-phenyl-4-benzyl-5- oxazolinone with ethyl iodide gave a dimer namely, 3-(benzoylamino)-3,5-dibenzylpyrrolidine-2,4-dione.Latvian Institute of Organic Chemistry, LV-1006 Riga. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 829–833, June, 1994. Original article submitted January 21, 1994.     

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.     

Microorganisms as reagents for transformations of 5α-steroids

Microbial activation of rings A, B, and C of 5-steroids is reviewed in connection with the prospects for the use of 5-steroids as a new starting material for the manufacturing of steroidal medicinal preparations. The combination of chemical synthesis and microbial methods of steroid transformation allows the successful solution of the problem of selective functionalization of steroid molecules, provided the suitable microorganisms are chosen and the conditions of their cultivation are optimized.Translated fromIzyestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 567–588, April, 1994.     

Two new 5α-adynerin-type compounds from Parepigynum funingense

<正>A new 5α-adynerin-type cardenolide,named funingenoside U(1),together with its aglycone,(17R)-3β-hydroxy-4β-acetoxy-8, 14β-epoxy-5α-card-20(22)-enolide,was isolated from the roots of Parepigynumfuningense.Their structures were established on the basis of spectral(MS,1D and 2D NMR) measurements and chemical evidences.     

Synthesis of 5 β-Chloro-4α-methoxysantonin Oxime

The newderivative 5-chloro-4-methoxysantonin oximewasprepared from5-chloro-4-methoxysantonin by reaction with hydroxylamine hydrochloride in the presence of pyridine. The structure was established by IR, UV, and PMR spectroscopies.     

Efficient approach to novel 1α-triazolyl-5α-androstane derivatives as potent antiproliferative agents

Stereoselective 1,4-Michael addition of azoimide to 17β-acetoxy-5α-adrost-1-en-3-one was carried out to furnish a 1α-azido-3-ketone, which was reduced to give the 3β- and 3α-hydroxy epimers in a ratio of 5 : 2. The Cu(I)-catalyzed 1,3-dipolar cycloaddition of the major isomer to terminal alkynes afforded 1α-triazolyl derivatives, which were deacetylated to the corresponding 3β,17β-diols or oxidized to the analogous 3-ketones. However, the ability of the minor 1α,3α-azidoalcohol to undergo similar cyclization was found to be affected significantly by the steric bulk of the substituents on the alkyne reaction partner. All triazolyl compounds were tested in vitro on three malignant gynecological cell lines (HeLa, MCF7 and A2780).     

Synthesis of 5α, 13α, 14α-Androstan-16-One and 5α, 13β, 14β—Androstan-16-One Using a Novel 17–16 Carbonyl Transposition

In the course of current work on the conformational analysis of cis-hydrindanones¹, we required 5α, 13α, 14α and 5α, 13β, 14β-androstan-16-one 5 and 10 the C and D rings of which provide rigid models of the two conformations of cis-hydrindan-2-one.     

A novel synthesis of N-acetyl-α-d-fucosamine 1-phosphate and uridine 5"-diphospho-N-acetyl-α-d-fucosamine

In connection with studies on the biosynthesis of capsular polysaccharides from Staphylococcus aureus, a new synthesis of uridine 5"-(2-acetamido-2,6-dideoxy--d-galactopyranosyl diphosphate) (uridine 5"-diphospho-N-acetyl--d-fucosamine) using 2-azido-3,4-di-O-acetyl-2,6-dideoxy--d-galactopyranosyl nitrate as the key intermediate was carried out. The reaction of this product with cesium dibenzyl phosphate smoothly affords the corresponding -glycosyl dibenzyl phosphate, which undergoes anomerization on treatment with BF₃·Et₂O and 2-bromopyridine to give -glycosyl dibenzyl phosphate in high yield. This product was then transformed into 2-amino-3,4-di-O-acetyl-2,6-dideoxy--d-galactopyranosyl phosphate, subsequently converted into 2-acetamido-2,6-dideoxy--d-galactopyranosyl phosphate and the target nucleoside diphosphate sugar.     

Novel Synthesis of 22,25-Dideoxyecdysone and Its 5α-Isomer

22,25-Dideoxyecdysone (1) and 5-22,25-dideoxyecdysone (1a) were prepared from cholesterol via a new scheme using the key intermediates 3-chloro-5-bromo-6-ketone 3, 3-chloro-7-bromo-6-ketone 4, and 2,7-dien-6-one 7.     

Conversion of Epiandrosterone Into 17β-Amino-5α-androstane

A new method for synthesizing 17-amino-5-androstane was developed based on tigogenin. The configuration at C-17 was proved by PMR.     

合成抗孕酮新药RU—486中间体3,3—乙撑二氧—5α,10α及5？…

采用薄层色谱成功地分离了３,３－乙撑二氧－△＾５（１０）,９（１１）－雌甾二烯－１７α（１－丙炔基）－１７β醇的环氧化产物３,３－乙撑二氧－５α,１０α－环氧－△＾９（１１）－雌烯－１７α（１－丙烯基）－１７β醇（简称Ｉα）和３,３－乙撑二氧－５β,１０β－环氧－△＾９（１１）－雌烯－１７α（１－丙炔基）－１７β醇（简称Ｉβ）,并对Ｉα和Ｉβ进行了定性和定量分析,其结果在红外谱图、核磁实验中得到验     

Oxidative Coupling of 4α,9-Diaza-1,2,4α,9α-tetrahydrofluorenes. 5. Reaction with o-Aminophenol and o-Aminothiophenol

Oxidative coupling of 4,9-diaza-1,2,4,9-tetrahydro-9H-fluorenes with o-aminophenol and o-aminothiophenol in the presence of MnO₂ gives o-hydroxyphenyl- and o-mercaptophenylquinonediimines, cyclization of which gives derivatives of phenoxazine and phenothiazine.     

4α-甲基-5α胆甾烷的合成及中间体立体化学的研究

本文报道用与文献不同的路线合成了4α-甲基-5α胆甾烷并研究了中间体的立体化学。