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1.
All four isomers of substituted 3-alkylthio-4-hydroxybutenes have been synthesised: both the geometry of the double bond and the relative stereochemistry of the two chiral centres are controlled.  相似文献   

2.
The isolation and structure determination of syncarpurea (1), a novel urea from Uvaria afzelii is reported.  相似文献   

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N-Acyl derivatives of D,L-acosamine and D,L-ristosamine were synthesized with high stereo selectivity utilizing intramolecular Michael addition of γ- and δ-carbomoyloxy-α,β-unsaturated esters.  相似文献   

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Palladium catalysed alkoxycarbonylation of heterocyclic halides affords a simple and versatile synthesis of both N and S heterocyclic esters where a range of catalysts have been studied and a method to employ inexpensive inorganic bases has been found.  相似文献   

8.
A new toxic metabolite was isolated from Penicilliumparaherquei and the structure was determined by X-ray diffraction analysis. The metabolite was designated as paraherquamide.  相似文献   

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Methods are described for the stereospecific conversion of hydrindenone 3 either to the corresponding trans fused or cis fused hydrindanone (1 or 2, respectively.)  相似文献   

12.
The isolation of a new metabolite of mixed biogenesis, balearone 1from the brown alga Cystoscirabalearica is described. The structure was determined by an X-ray diffraction analysis.  相似文献   

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Structure of phaseolinone, a phytotoxin isolated from the fungus Macrophima phaseolina (Tassi) Gold, has been established as 1.  相似文献   

15.
Aszonalenin (1) has been isolated from Aspergillus zonatus together with LL-S490β (2) and the structure of 1 has been established by spectroscopic evidences and chemical transformation.  相似文献   

16.
J Leitich 《Tetrahedron letters》1980,21(32):3025-3028
The relative rates of formation of cis and trans [2+2]cycloadducts of benzyne to cis, trans- and cis, cis-1,5-cyclooctadiene, trans- and cis-cyclooctene are discussed and properties of the adducts (e.g., their unusual hydrogenation) are described.  相似文献   

17.
The structure elucidation and synthesis of WS 5995, produced by Streptomycesauranticolor, were described.  相似文献   

18.
Pinacol E-1-trimethylsilyl-1-propene-3-boronate reacts with aldehydes to form (±)-(R*,S*)-3-trimethylsilyl-4-hydroxy-1-alkenes, which can be deoxysilylated stereoselectively to either 98% Z or 99% E 1,3-dienes, including the separate components of the red bollworm moth pheromone.  相似文献   

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The structure of koumine, an indole alkaloid from Gelsemiumelegans Benth., was determined by a X-ray crystallographic study.  相似文献   

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