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1.
The structures of the -illudalane sesquiterpenoids cybrodol ), isocybrodol (), cybrodic acid (), cybrodal (), and trisnorcybrodolide (), are presented. These are the first -illudalanes to be reported. 相似文献
2.
Takeshi Imanishi Noriyuki Yagi Hiroaki Shin Miyoji Hanaoka 《Tetrahedron letters》1981,22(40):4001-4004
A new synthesis of (±)-ibogamine () and (±)-epiibogamine (), involving the intramolecular Michael addition of the keto unsaturated ester (), is described. 相似文献
3.
The novel structures assigned by Yunusov et al to the C19-diterpenoid alkaloids, acomonine (), iliensine (), 14-dehydroiliensine (), and 14-bensoyliliensine () have been found to be in error. We have demonstrated that these alkaloids are identical with the well-known alkaloids, delsoline (), delcosine (), 14-dehydrodeloosine (), and 14-benzoyldelcosine (), respectively. 相似文献
4.
Joseph Almog Jack E. Baldwin Maxwell J. Crossley John F. Debernardis Robert L. Dyer Joel R. Huff Mary K. Peters 《Tetrahedron》1981,37(21):3589-3601
The synthesis of “capped porphyrins” (), (), and (), and their (chloro)iron(III), iron(II), cobalt (II), and zinc(II) complexes is reported. These complexes serve as models for the active site of the oxygen binding haemoproteins. In addition to reversible binding of dioxygen by each of the iron (II) porphyrin complexes, the 1-methyl-imidazole-(“C3-capped porphyrin”) iron (II) complex () reacts reversibly with carbon monoxide, in solution at 25°C. 相似文献
5.
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
6.
Shinichi Uesato Shinichi Ueda Koji Kobayashi Masao Miyauchi Hiroyuki Inouye 《Tetrahedron letters》1984,25(5):573-576
Administration of 2H- or 13C-labeled monoterpenes to f. cell suspension cultures demonstrated that iridoid glucosides of the suspension cultures are biosynthesized, after iridodial cation formation from 10-oxocitral (3), via 8-epiiridodial (13), 8-epiiridotrial (14), boschnaloside (8-epiiridotrial glucoside) (12) and dehydroiridotrial glucoside (8). In addition, the coexistence of a route via iridodial cation (4), dehydroiridodial (6), dehydroiridotrial (15) and dehydroiridotrial glucoside (8) is conceivable. 相似文献
7.
Starting from 4, 5, 12, 13-tetrakis(methoxycarbonyl)[2.2]paracyclophane (), the penta-(), hexa-(–), hepta-(), and octamethyl-() derivatives have been prepared by a repetitive formylation-reduction sequence. 相似文献
8.
The protection of the 6-oxo group of deoxyguanosine with the 2-trimethylsilylethyl (), phenylthioethyl (), 4-nitrophenylthioethyl (), 4-nintrophenethyl (), and cyanoethyl () groups is described. Each protecting group is introduced in good yield and is cleaved under mild conditions. Compatibility with the various approaches to oligonucleotide synthesis is discussed. 相似文献
9.
Motomasa Kobayashi Yutaka Kiyota Satomi Orito Yoshimasa Kyogoku Isao Kitagawa 《Tetrahedron letters》1984,25(34):3731-3734
Five new pregnene-type steroidal glycosides, named pregnedioside -a (), 4′-O-acetyl-pregnedioside-a (), 3′-O-acetyl-pregnedioside-a (), pregnedioside-b (), and 4′-O-acetyl-pregnedioside-b (), were isolated from an Okinawan soft coral of Alcyonium sp. and their structures were elucidated. These are rare examples of steroidal gylcosides from soft coral. 相似文献
10.
Reaction of the cyclic 1, 3-dicarboxylic acid derivatives (), () and () with (R)- or (S)-citronellal (/) gives the enantiomeric tricyclic dihydropyrans (), (), () and (), probably via a 100% stereocontrolled intramolecular cycloaddition. 相似文献
11.
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
12.
Athelstan L.J. Beckwith George Phillipou Algirdas K. Serelis 《Tetrahedron letters》1981,22(29):2811-2814
The rates and stereochemistry of ring closure of the radicals (), (), (), and () have been determined and rationalised. 相似文献
13.
The 6-hydroperoxy-1,4-cyclooctadiene (), which is formed in the photosensitized oxygenation of 1,5-cyclooctadiene (), affords on further singlet oxygenation 5,8-dihydroperoxy-1,3-cyclooctadiene (), which via triphenylphosphine reduction leads to -5,8-dihydroxy-1,3-cyclooctadiene () and subsequent pyridinium chlorochromate oxidation to 1,3-cyclooctadien-5,8-dione (). 相似文献
14.
Unprotected thymidine and uridine react with 4-nitrophenylsulfonyl ethene () in a base catalyzed Michael type addition to give O4-(4-nitrophenylsulfonylethyl)thymidine-() and -uridine (), respectively. The 4-nitrophenylsulfonylethyl group is cleaved within 2.5 hours at 50–55°C by concentrated aqueous ammonia, via β-elimination. 相似文献
15.
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
16.
Emir Valencia Inge Weiss Sadiqa Firdous Alan J. Freyer Maurice Shamma Alejandro Urzús Victor Fajardo 《Tetrahedron》1984,40(20):3957-3962
Three Chilean barberries, Mart. ex Schult., . Hook and [ulbar|B. Phil. (Berberidaceae), have yielded several new isoindolobenzazepine and protoberberine alkaloids. Novel isoindolobenzazepines are (±)-13-deoxychilenine (), pictonamine (), chileninone (), (±)-chileniimi () and (±)-palmanine (). Highly oxidized protoberberines of particular interest include (±)-O-methylprechilenine () and (±)-prepseudopalmanine (), together with 13-methoxy-8-oxyberberine (). Isoindolobenzazepine alkaloids arise biogenetically from the rearrangement of highly oxidized protoberberines. 相似文献
17.
Herbert L. Holland David B. MacLean Russell G.A. Rodrigo Richard F.H. Manske 《Tetrahedron letters》1975,16(49):4323-4326
The reduction product of dehydrocordrastine, , with di-isobutylaluminum hydride spontaneously rearranged to the spirobenzylisoquinolines and , analogous to the alkaloids sibiricine (), corydaine (), and yenhusomidine (). 相似文献
18.
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
19.
Antonio G. Gonzalez Dulce M. Estrada Julio D. Martin Victor S. Martin Cirilo Perez Ricardo Perez 《Tetrahedron》1984,40(20):4109-4113
The methanol extract of the sponge Spongia officinalis from Pt. Guimar, Tenerife (Canary Islands) contained new diterpenoids which inhibited the growth of microbes. The structures of the new diterpenes isolated were determined as; 11β-hydroxyspongi-12-en-16-one (), 11β-acetoxyspongi-12-en-16-one (), 7β,11β-dihydroxy8pongi-12-en-16-one (), and 7β,11α-dihydroxy-spongi-12-en-16-one (), by spectral and chemical degradation studies. The previously reported diterpenes isoagatholactone () and aplysillin () were also found in the extract. 相似文献
20.
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