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1.
HongYanZHENG ShaoBaiLI 《中国化学快报》2005,16(1):20-22
6, 9, 11-Trihydroxy-6a, 12a-dehydrorotenoid 1 (coccineone B) was synthesized from 2-hydroxybenzaldehyde 2 and phloroglucinol. 相似文献
2.
O. Yu. Slabko N. V. Ageenko G. A. Verbitski V. A. Kaminski 《Chemistry of Heterocyclic Compounds》2002,38(2):226-230
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. 相似文献
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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). 相似文献
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The title compound, 4β,6α,9α-trimethy-2-carboxyltricyclo[6.3.0.0^(4,5)]undec-2-ene, is a sesquiterpene which was first isolated from Ligularia caloxantha and characterized by MS and NMR. In addition, the structure was determined by X-ray single-crystal diffraction. It crystallizes in orthorhombie, space group P212121 with a = 8.197(2), b = 14.876(3), c = 22.281(6) A, α = β = γ = 90°, V = 2716.9(11) ]A^3, Z = 8, C15H22O2, Mr = 234.34, Dc = 1.146 g/cm^3, μ(MoKa) = 0.074 mm^-1, F(000) = 1024, the final R = 0.0384 and wR = 0.0856 for 6200 independent reflections (Rint = 0.066) and 2538 observed ones (I 〉 2σ(I)). In the molecule, there are three fused five-membered rings; while in this crystal form, the asymmetric unit contains two molecules of the same hand and they are linked together by two intermolecular O-H...O hydrogen bonds to form a dimer. 相似文献
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I. S. Levina L. E. Kulikova V. V. Kachala L. L. Khemchyan 《Russian Chemical Bulletin》2013,62(9):2037-2040
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. 相似文献
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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. 相似文献
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2,3,4,6-Tetrar-O-methyl-α-D-glucopyranosyl bromide (3) is conveniently prepared by treatment of 2,3,4,6-tetra-O-methyl-D-glucose with HBr. This procedure is easier and produces higher yields than previously reported syntheses. 相似文献
10.
N. V. Kovganko Yu. G. Chernov S. N. Sokolov Zh. N. Kashkan V. L. Survilo 《Chemistry of Natural Compounds》2009,45(2):200-204
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. 相似文献
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K. M. Turdybekov S. V. Lindeman T. V. Timofeeva Yu. T. Struchkov 《Chemistry of Natural Compounds》1991,27(2):169-173
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. 相似文献
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《Tetrahedron: Asymmetry》2001,12(8):1211-1217
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. 相似文献
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Two procedures were developed for the synthesis of 17-alkyl-8,9-estra-1,3,5(10)-triene-3,14,17-triols from 3-methoxy-estra-1,3,5(10),8(9),14(15)-pentaene-17-one (1) using photosensitized oxidation by atmospheric oxygen or ionic hydrogenation in the presence of oxygen. It was shown that 17-hexynyl-8,9-estra-1,3,5(10)-triene-3,14,17-triol (23) and its 3-methoxy derivative (26) inhibit K+,Na+-ATPase, with inhibition degree increasing on introduction of an oxygen-containing substituent into position 17. For the first time steroids were found with 2-adrenoblocking action.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 207–212, January, 1993. 相似文献
16.
Francisc Potmischil Helmut Herzog Joachim Buddrus Mircea D. Gheorghiu 《Monatshefte für Chemie / Chemical Monthly》2000,131(4):345-352
Summary. The stereoselectivities of the quaternization reactions of (4aα,8aβ,9aβ,10aα)- and (4aα,8aα,9aβ,10aα)-tetradecahydro-10-methylacridine
with methyl- and ethyl iodide as well as those of (4aα,8aβ,9aβ,10aα)- and (4aα,8aα,9aβ,10aα)-10-ethyl-tetradecahydroacridine
with methyl iodide were investigated using 13C NMR spectroscopy including 13C-labelling where appropriate. The methylations of both N-methyl amines occur by predominant (60% and 75%, respectively) equatorial
approach, their ethylations occur sterospecifically by equatorial approach, and the methylations of the N-ethyl amines occur
by highly stereoselective (> 90%) axial approach of the quaternizing reagent.
Received October 27, 1999. Accepted November 22, 1999 相似文献
17.
A. M. Turuta N. E. Voishvillo A. V. Kamernitskii N. V. Dzhlantiashvili A. A. Korobov 《Russian Chemical Bulletin》1992,41(8):1482-1484
A preparative method was proposed for the preparation of pregn-4-ene-9,16,17-triol-3,20-dione 16,17-acetonide (2) from 5-H-pregn-16-en-3-ol-20-one (1). The key stage in the proposed sequence of the reactions is the microbiological 9-hydroxylation and introduction of the 4-en-3-one grouping into the molecule of1 by R- and S-dissociative forms of the Rhodococcus sp. strain.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1898–1901, August, 1992. 相似文献
18.
A novel taxane with an unprecedented hemiacetal ring between C-13 and C-9 was isolated from the needles of Taxus cuspidata. The structure was characterized as (12αH)-2α,10β-diacetoxy-5α-cinnamoyloxy-9α,13α-epoxytax-4(20)-ene-11β,13β-diol (1). This is the first example of a natural taxane with a C-13 and C-9 oxygen bridge to form an unusual 6/8/6/6-membered ring system. 相似文献
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We studied various methods for synthesizing 2,3-dihydroxy-
4,7
-6-ketosteroids, which are structural analogs of the ecdysteroids diaulusterols A and B. 相似文献