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1.
A route towards I-oxygenated eudesmanolides, via a (2+2) photocycloaddition reaction for constructing the decalin framework is described. The following natural substances have been synthesized. (=)-dihydroreynosin (), (±)-1- oxo-dihydronmagnolialide (), (±)-maritimin (), (±)-dihydromagnolialide (), (±)-magnolialide (), (±)-dihydrosantamarine (). Also a synthesis of (±)--santonin () is presented. 相似文献
2.
Waldemar Adam Klaus Zinner Adolf Krebs Hermann Schmalstieg 《Tetrahedron letters》1981,22(46):4567-4570
The rather stable 1,2-dioxetanes () and (), derived from the sterically stabilized cyclobutadiene (), exhibit distinct enhanced chemiluminescence behavior, namely energy transfer chemiluminescence (ETC) for () and electron exchange chemiluminescence (EEC) for (). 相似文献
3.
A new and convenient synthesis of 2-isopropylfuro-(2,3-b)quinolines () from 3-(3-methylbut-1-enyl)-2-quinolones () is described. A neat synthesis of the alkaloids (±)-lunacrine (), (±)-lunasine () and (±)-demethoxylunacrine () is also reported. 相似文献
4.
Reaction of the hydroaromatic compounds () and () with lithium-diisopropylamide followed by phenylselenenyl chloride gives the selenides () and () resp. (), which form exclusively the phenols () resp. () after oxidation with 3-chloroperbenzoic acid in the presence of 3,5-dimethoxyaniline (). 相似文献
5.
-() and -1,3-Butadienylcyclobutane (), all--1-(1 ,3-butadieny1 )-2- vinylcyclobutane (), and all--1,2-bis(1,3-butadienyl)cyclobutane () have been prepared from readily available starting materials, and pyrolyzed to various cyclohexenes. 相似文献
6.
W.E. Barnette 《Journal of fluorine chemistry》1984,26(2):161-164
S-Methyl()-2,2,2-trifluorothioacetohydroximate (), S-methyl()-2,2,3,3,3-pentafluorothiopropiohydroximate (), and S-methyl()-2,2,3,3,4,4,4-heptafluorothiobutyrohydroximate () were prepared by reaction of the corresponding perfluoroalkyl nitriles , , and with methanethiol and hydroxylamine hydrochloride. 相似文献
7.
Yoshito Tobe Yasuyoshi Ueda Masaharu Matsumoto Yasuo Sakai Yoshinobu Odaira 《Tetrahedron letters》1982,23(5):537-538
Bicyclo[6.2.2]dodecadienes (), (), and () having two bridgehead double bonds were synthesized by the pyrolysis of the acetate (). 相似文献
8.
Hisashi Ishii Tsutomu Ishikawa Ih-Sheng Chen Sheng-Teh Lu 《Tetrahedron letters》1982,23(42):4345-4348
The structures of three new prenylphenyl propanoids, wutaiensol (), wutaiensal (), and methyl demethoxywutaiensate () were established by correlating with S-rutaretin methyl ether () or S-marmesin () by chemical means. The structure of wutaialdehyde (), a related compound, was also established by total synthesis of the racemate and by correlating with . Preliminary piscicidal test on these compounds disclosed that and are weakly bu distinctly positive. 相似文献
9.
Tatsuhiko Nakano A.C. Spinelli A. Martín A. Usubillaga Andrew T. McPhail Kay D. Onan 《Tetrahedron letters》1982,23(35):3627-3630
cleavage of the epoxide () of methyl (-)-kaur-9(11)-en-19-oate () with boron trifluoride-ether in benzene and in acetic anhydride yielded () and (), respectively. On epoxidation with -chloroperbenzoic acid in the presence of -nitrosomethyl urea, () suffered a backbone rearrangement to form (). 相似文献
10.
Pyrolysis of homoadamant-3-ene (), generated from 1-adamantylcarbene (), leads to the same three olefins (, , and ) that are produced from pyrolysis of 3-homoadamantyl acetate (). 相似文献
11.
The biomimetic reactions of epoxygermacrene-D () with basic alumina afforded three new interesting compounds (, , and ), two of which ( and ) have the same carbon skeleton as that of periplanone-A (), a sexual stimulant for the American cockroach. The remaining one () is a bicyclo[3.1.0]hexane derivative, from whch an axisonitrile-3 type compound () has been produced. Finally, preisocalamendiol () was also converted into . 相似文献
12.
Reduction of the indole-1-carboxaldehydes (-) with borane /THF gives the 1-methylindoles () in 42-91-% yields together with the di(indolylmethyl)ethers (), the indolyl-methyl indolines (), the unsymmetric ether() and the indolenine () as the minor products, except . This appears to be the first report on the formation of symmetric ethers in the borane/THF reduction of an oxygen function. The formation of and from and implies that electrophilic substitution takes place primarily at position 3 of 3-substituted indoles, did not form the corresponding probably because of steric hindrance. These results are discussed in relation to the mechanisms of borane/THF reduction, origin of the different products and electrophilic substitution in 3-substituted indoles. 相似文献
13.
Unambiguous synthesis of 2-methyl-3-isopropenylanisole () and 2-isopropenyl-3-methylanisole () has led to revision, from () to (), of the structure assigned to a monoterpene phenol ether isolated from . 相似文献
14.
S.C. Pakrashi B. Achari E. Ali P.P. Ghosh Dastidar R.R. Sinha 《Tetrahedron letters》1980,21(27):2667-2670
Alangimarine (), alamarine () and alangimaridine (), isolated from the seeds of the title plant, have been characterised as a new class of alkaloids. Presence of isoalamarine () in the stem-bark is indicated. 相似文献
15.
Reaction of nerol () with thallium(III) perchlorate gave 6-oxabicyclo[3.2.1]octane derivatives () and (), and 6,9-dioxabicyclo[3.3.1]nonane derivatives () as the cyclization products. 相似文献
16.
Ernst-Ulrich Würthwein Jayaraman Chandrasekhar Eluvathingal D Jenmis Paul von Ragué Schleyer 《Tetrahedron letters》1981,22(9):843-846
Semi-empirical (MINDO/3 and UNDO) MO calculations on highly strained planar tetracoordinate carbon candidates indicate the central carbons in - [4.4.4.4] fenestrane () to have pyramidal () and in trans-[4.4.4.]fenestrane () to have distorted tetrahedral () geometries. In [2.2.2.2]paddlane (), the two central carbons are pentacoordinate. Each is nearly coplanar with four carbon neighbours; additionally, the two bridgehead carbons are connected by a single bond (). 相似文献
17.
Tetsuji Kametani Keiichiro Fukumoto Hiroshi Kurobe Hideo Nemoto 《Tetrahedron letters》1981,22(37):3653-3656
The acid catalysed cyclization of β-hydroxy selenide (), which was prepared from nerolidol () the epoxide (), was carried out to give bicyclic ether () directly which was further transformed into caparrapl oxide (). 相似文献
18.
Naomichi Furukawa Tsuyoshi Morishita Takeshi Akasaka Shigeru Oae 《Tetrahedron letters》1979,20(41):3973-3976
The reaction of thiolsulfinates () with rifluoro- or richloroacetic anhydride gives sulfinyl carboxylates () via formation of sulfenyl trihaloacetate (), which in the presence o olefins, can be trapped to afford β-trifluoro- or β-richloroacetoxysulfides () in good yields. 相似文献
19.
A new synthesis of the pyranoquinolone alkaloids flindersine (), 8-methoxyflindersine (), N-methylflindersine (), zanthobunglanine () oricine () and veprisine () and the prenylquinolone alkaloids atanine (), preskimmianine () N-methylatanine (), O-methylglycosolone () and N-methylpreskimmianine () is described. 相似文献
20.
Reaction of () and () with the acetal () in presence of trimethylsilyl trifluoromethanesulfonate at ?70° C gives the α-glucosides () and (), whereas () and () lead to the β-glucosides () and (). At 0° C reaction of () with the acetals () gives exclusively the α-glucosides (). 相似文献