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1.
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
2.
Claudio Fuganti Piero Grasselli Stefano Servi Carlo Zirotti 《Tetrahedron letters》1982,23(41):4269-4272
The C4erythro and threo diols (7) and (8) are converted either into the chiral epoxides (13) and (15) or into the enantiomers (14) and (16); the epoxide (13) is used as chiral synthon for the preparation of (3,4) 4-methyl-3-heptanol (21). 相似文献
3.
Hideo Kigoshi Yoshikazu Shizuri Haruki Niwa Hiyoyuki Yamada 《Tetrahedron letters》1982,23(14):1475-1476
Isolation and structural elucidation of two new acetylenic polyenes, -laurencenyne and -neolaurencenyne from the marine red alga were carried out, the former compound very recently being proposed to be a biosynthetic precursor of the C15 halogenated cyclic ethers, and . 相似文献
4.
The nitration of -cresol by nitric acid in aqueous sulphuric acid involves ~40% -substitution at CMe. The 4-methyl-4-nitrocyclohexa-2,5-dien-1-one (I) formed undergoes an acid-catalysed rearrangement to 4-methyl-2-nitrophenol. 相似文献
5.
Treatment of halo--methylphosphonium salts with potassium fluoride and halogen (I2, Br2, ICl, IBr) gives modest yields of halo--methanes. This method of preparation augments the classical Hunsdiecker approach to these materials. 相似文献
6.
W.David Ollis Julia Stephanidou Stephanatou J.Fraser Stoddart Gulten G. Unal David J. Williams 《Tetrahedron letters》1981,22(23):2225-2228
An X-ray structure analysis shows that the 5, 18-dimethyl derivative () of the title compound () crystallises from xylene as a 1:1 inclusion compound in which the host molecules adopt propeller-like conformations ( and *) with almost perfect 2 symmetry. Dynamic 1H n.m.r. spectroscopy shows that the 5, 18-dibenzyl derivative () of () forms a 1:1 inclusion compound with ethanol in the solid state and undergoes ring inversion ( ? *) between enantiomeric propeller-like conformations in solution against a barrier of 21.1 kcal mol?1 相似文献
7.
The stereospecific syntheses of three isomers of 7-hydroxy-5,6-epoxy heptanoic acid methyl ester, , and , have been achieved via a -glycoside route. 相似文献
8.
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
9.
O.R. Martin 《Tetrahedron letters》1985,26(17):2055-2058
Upon treatment with tin(IV) chloride, perbenzylated glycofuranosyl acetates such as 3 or 6 undergo an unusual, intramolecular α--arylation resulting from the internal Friedel-Crafts alkylation of the 2--benzyl substituent. 相似文献
10.
The two C6, C7 substituted title compounds have been synthesized via stereoselective 5--Trig ringclosures starting from (E)-resp. (Z)-4-nonene-1-yl bromide and 3,5-morpholinedione. 相似文献
11.
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
12.
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
13.
Sterepolide and dihydrosterepolide, new sesquiterpenes isolated from the fungus , are assigned structures and , respectively. The assignments are based mainly on spectroscopic studies and similarities to isolactarorufin (). A possible mode of biogenesis of these isolactarane type sesquiterpenes is discussed. 相似文献
14.
Judith Polonsky Zoīa Varon Thierry Prange Claudine Pascard Christian Moretti 《Tetrahedron letters》1981,22(37):3605-3608
Simarinolide and Guanepolide are new quassinoids with a C25 basic skeleton isolated from a member of the French Guyanan Simaroubaceae, Simaba cf orinocensis H.B.K. The structure was established by spectral means and that of by X-ray diffraction analysis. The previously known simarolide was also isolated. 相似文献
15.
Roshantha A.S. Chandraratna Robert R. Birge William H. Okamura 《Tetrahedron letters》1984,25(10):1007-1010
The electronic absorption spectra of the four new 12---locked retinals (1a–1d) bearing 7-, 11- double bond geometries are described and compared with those of analogous 7-, 11--geometries (1e–1h) and parent retinals (2a-h). 相似文献
16.
Structure of biluciferyl (luciferyl radical dimer), which is produced by chemical oxidation of . luciferin with such as ferricyanide, was determined to be the symmetric 5,5′-dimer of . luciferin. It gives light in the presence of . luciferase, although the bioluminescent rate is very low. We suggest that the biluciferyl is an intermediate in the oxidation of the luciferin to . luciferinol. 相似文献
17.
The synthesis of N-benzoyl--ristosamine (7) from natural tartaric acid through the intermediacy of the δ- and γ- lactones (4) and (6) is reported. 相似文献
18.
Although the hydrochloride of -4--butyl-1-phenyl--1-(N-piperidyl)cyclohexane crystallizes in the conformation with axial -butyl, it exists as an almost equimolar mixture of the two chair conformers in CD2 Cl2 solution. The position of equilibrium allows one to calculate ΔG°-Bu as ?4.9 kcal/mol. 相似文献
19.
Superoxo Co(III) complexes derived from Co(Salpr) and [Co(CN)5]3? reacted with 2,6-di--butyl--benzoquinone methides to give 2,6-di--butyl--benzoquinone and 2,6-di--butyl-2,5-cyclohexadienonespirooxiranes as the main products, which are considered to result from nucleophilic attack by the superoxo species on the exo double bond of the quinone methides. 相似文献
20.
Naoko Morisaki Jun Furukawa Hisayoshi Kobayashi Shigeo Iwasaki Shigeo Nozoe Shigenobu Okuda 《Tetrahedron letters》1985,26(39):4755-4758
Deuterium labeled -6-protoilludene () was synthesized and fed to the illudin-producing fungus (ATCC 11719). The hydrocarbon () was incorporated into illudin-M () and -S (). 相似文献