共查询到20条相似文献,搜索用时 31 毫秒
1.
Two steroids, 3-oxo-chol-4-ene-24-oic acid () andi ts unsaturated analog have been isolated from the dorid nudibranch , and the acid has been shown to have antifeedant properties. 相似文献
2.
Giovanni Fronza Claudio Fuganti Piero Grasselli Giulio Marinoni 《Tetrahedron letters》1979,20(40):3883-3886
The enantiomeric alcohols () and (), obtained from (2,3) tartaric acid and, respectively, -threonine, have been used to construct the C6, enantiomeric deoxy amino sugar derivatives () and () 相似文献
3.
Nobuyasu Enoki Ryoichi Ishida Shiro Urano Takeshi Matsumoto 《Tetrahedron letters》1985,26(14):1731-1734
The structures , , and have been proposed for three new diterpenes from mainly on the basis of spectroscopic evidence. 相似文献
4.
Hans Achenbach Andreas Mühlenfeld Benno Weber G.U. Brillinger 《Tetrahedron letters》1982,23(45):4659-4660
The new compounds – and have been isolated from cultures of 相似文献
5.
Toshihiro Hashimoto Motoo Tori Zenei Taira Yoshinori Asakawa 《Tetrahedron letters》1985,26(52):6473-6476
Four novel fusicoccane diterpenoids, fusicoplagins A, B, C, and D, have been isolated from the liverwort subsp. and the structures determined by spectroscopic methods, chemical transformations, and X-ray crystallographic analysis. 相似文献
6.
Claudio Fuganti Piero Grasselli Giuseppe Pedrocchi-Fantoni 《Tetrahedron letters》1981,22(40):4017-4020
The synthesis of N-benzoyl--daunosamine (14) from the C4 aldehyde (2b), prepared from -threonine, through the intermediacy of the C7 adduct (7a) is reported 相似文献
7.
A new ichthyotoxic toxin was isolated from the unialgal culture of the deleterious Florida red tide organism, Davis (Syn. ), and its structure was elucidated. 相似文献
8.
Richard E. Moore Walter P. Niemczura Oliver C.H. Kwok Suresh S. Patil 《Tetrahedron letters》1984,25(36):3931-3934
The structure of phaseolotoxin, a toxin produced by cultured pv. , the causal agent of halo blight disease in bean plants is revised to 3. The structure of octicidin, isolated from leaves of bean plants infected with pv. . has been determined to be 4, a protease degradation product of 3 which is formed in the plant. 相似文献
9.
N-Acyl derivatives of ,-acosamine and ,-ristosamine were synthesized with high stereo selectivity utilizing intramolecular Michael addition of γ- and δ-carbomoyloxy-α,β-unsaturated esters. 相似文献
10.
Eiichi Kitazawa Akira Ogiso Shuji Takahashi Masaaki Kurabayashi Harumitsu Kuwano Tadashi Hata Chihiro Tamura 《Tetrahedron letters》1979,20(13):1117-1120
Two new diterpenelactones named plaunol A () and B () exhibiting anti-Shay ulcer activity were isolated from Thai medicinal plant, . Structure of was determined by X-ray analysis of its -bromobenzoate and structure of was deduced from the results of chemical correlation and the spectral data. 相似文献
11.
E.L. Ghisalberti P.R. Jefferies T.A. Mori B.W. Skelton A.H. White 《Tetrahedron》1985,41(12):2517-2526
Three diterpene acids, representing a new class of bicyclic diterpenes, have been isolated from F. Muell. (Euphorbiaceae). Spectroscopic and X-ray cryatallographic evidence for their structure is presented. A rationale for their origin modification of the casbane skeleton is given. 相似文献
12.
The 1H and 13C nmr spectra of , -9-oxobicyclo[3.3.1]nonane-2,4-dicarboxylic acid, 3, in DMSO-d6 or alkaline D2O, clearly show that it exists in a --conformation with carboxyl groups, thus being the first case of - preference of a bicyclo[3.3.1] nonan-9-one due to the presence of ,-2,4- substituents. 相似文献
13.
3-Indazol-3-one has been generated by thermolysis of (-azidobenzoyl)iminopyridinium ylide and trapped as its Diels-Alder cycloadducts with several dienes. 相似文献
14.
Bacteria-infected leaves of two species contain isoprenyl 6a-hydroxy-pterocarpinoids including two novel compounds canescacaroin () and clandestacarpin (), for which structure and stereochemistry have been determined. 相似文献
15.
G. Cimino S. De Stefano L. Minale R. Riccio K. Hirtosu J. Clardy 《Tetrahedron letters》1979,20(38):3619-3622
The structures of two unique sesterpenes, toxislylide A and B, have been deduced by chemical, spectral, and x-ray crystallographic studies. They are components of the sponge . 相似文献
16.
Hiroyuki Kikuchi Yasumasa Tsukitani Yasuji Yamada Kazuo Iguchi Steven A. Drexler Jon Clardy 《Tetrahedron letters》1982,23(10):1063-1066
The structure and absolute stereochemistry of lemnalol (1), a new ylangene-type sesquiterpenoid isolated from the soft coral Verseveldt, has been established by spectroscopic, chemical, and x-ray crystallographic analyses. 相似文献
17.
The amino acid tyrosine has been shown to be the specific precursor of the isonitrile acid produced by (Bon.) Bain. aggr. 相似文献
18.
J Leitich 《Tetrahedron letters》1980,21(32):3025-3028
The relative rates of formation of and [2+2]cycloadducts of benzyne to , - and , -1,5-cyclooctadiene, - and -cyclooctene are discussed and properties of the adducts (e.g., their unusual hydrogenation) are described. 相似文献
19.
Two minor lipid components of the brown seaweed were characterized as (all Z) - 5′,7′-dihydroxy-2′-nonadeca-4,7,10,13,16-pentenyl-chrome chromone () and 5′,7′-dihydroxy-2′-pentadecylchrome (). 相似文献
20.
The structure of engleromycin isolated from Hennings has been established as by spectral techniques. 相似文献