- Total synthesis of ochnaflavone
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The first total syntheses of ochnaflavone, an asymmetric biflavone consisting of apigenin and luteolin moieties, and the permethyl ether of 2,3,2'',3''-tetrahydroochnaflavone have been achieved. The key steps in the synthesis of ochnaflavone were the formation of a diaryl ether and ring cyclization of an ether-linked dimeric chalcone to assemble the two flavone nuclei. Optimal experimental conditions for the oxidative cyclization to form ochnaflavone were established.
- Ndoile, Monica M.,Van Heerden, Fanie R.
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- Total synthesis of polymorphatin A, a macrocyclic bisbibenzyl with boat configured arenes
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Polymorphatin A was reported as a constituent of Marchantia polymorpha in 2007 following much speculation as to its likely existence as a natural product. Interest was rekindled when a claimed total synthesis revealed inconsistencies in spectral data betw
- Almalki, Faisal A.,Sun, Wei,Light, Mark E.,Harrowven, David C.
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- Synthesis and degranulation-inhibiting activities of the proposed apteniols B, C, and G
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The synthesis of compounds with the structures proposed for the oxyneolignan apteniols B, C, and G is described. The diphenyl ether skeletons of the proposed apteniols were formed via Ullmann ether synthesis. In particular, the spectral data for the synth
- Noshita, Toshiro,Tai, Akihiro,Nishikawa, Hikaru,Ikeda, Kaoru,Ouchi, Hidekazu,Hamada, Yoshitomo,Saito, Akiko,Yamada, Teiko
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p. 1743 - 1749
(2015/11/24)
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- Entropically favorable macrolactamization. Synthesis of isodityrosine peptide analogues by tandem Erlenmeyer condensation-macrolactamization
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Macrolactams containing a modified isodityrosine moiety were assembled by direct addition of a bis-4-aryliden-5(4H)-oxazolone, derived by double Erlenmeyer condensation of diaryl ether dicarboxaldehydes and an α,ω- diamine, derived from the same precursor. Tandem acylation of diamines with the bis-Erlenmeyer oxazolone gave macrolactams in yields of up to 30%. TECM demonstrates an entropically controlled 28-membered ring closure and allows rapid access to a variety of cyclic isodityrosine peptide analogues of the biologically active natural product bastadin-5.
- Bailey,Molinski
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p. 2500 - 2504
(2007/10/03)
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- Efficient stereoselective preparation of protected isodityrosines
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A method for stereoselective preparation of isodityrosines with identical and orthogonal protecting groups is reported. The isodityrosines holding identical protecting groups were prepared from isovaniline in a three step procedure, in 50-64% yield (> 98% ee, 84-96% de). Isodityrosine holding four orthogonal groups was prepared in four steps from isovaniline in 20% total yield (> 98% ee, 87% de).
- Jorgensen, Kare.B.,Gautun, Odd.R.
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p. 10527 - 10536
(2007/10/03)
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- Bibenzyl derivatives from Pellia epiphylla
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Reinvestigation of the phenolic constituents from a diethyl ether extract of gametophytes of Pellia epiphylla yielded pellepiphyllin, 7- hydroxypellepiphyllin, perrottetin E, perrottetin E-11-methyl ether, 14'- hydroxyperrottetin E, 10'-hydroxyperrottetin E, 10'-hydroxyperrottetin E-11- methyl ether, 10,10'-dihydroxyperrottetin E and 13',13'''-bis(10'- hydroxyperrottetin E). The structures of three bisbibenzyls published earlier are revised. The new structures have been elucidated by two-dimensional NMR- techniques and chemical synthesis. In contrast to previous publications, pellepiphyllin has been found as a constituent of P. epiphylla.
- Cullmann, Frank,Becker, Hans,Pandolfi, Enrique,Roeckner, Eckard,Eicher, Theophil
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p. 1235 - 1247
(2007/10/03)
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- SYNTHESES BASED ON β-PHENYLETHYLAMINES. VI. SYNTHESIS AND MASS-SPECTROMETRIC PROPERTIES OF BIS-β-PHENYLETHYLBENZYLAMINES AND THE PRODUCTS OF THEIR METHYLATION
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Fourteen previously undescribed bases of the bis-β-phenylethylbenzylamine series with a central diphenyl ether group differing by the relative positions of the oxygen bridge and the β-phenylethylbenzylamine substituent have been synthesized.The main directions of the fragmentation of these compounds under electron impact are competing or successive processes of cleavage of the benzyl bonds, accompanied by the structure-dependent transfer of hydrogen atoms.
- Baratov, N. U.,Mil'grom, E. G.,Vinogradova, V. I.,Rashkes, Ya. V.,Yunusov, M. S.
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p. 748 - 759
(2007/10/02)
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- THE ISOLATION AND TOTAL SYNTHESIS OF CADABICINE METHYL ETHER
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A new spermidine alkaloid, cadabicine methyl ether (1) has been isolated from stem bark of two capparidacious plants, Cadaba farinosa, Forssk., and Crataeva nurvala Bunch-Ham, using the same isolation procedure. The structure of (1) was determined by spec
- Ahmad, Viqaruddin,Amber, Aziz-Ur-Rehman,Fizza, Kaniz,Arif, Shoaib
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p. 475 - 479
(2007/10/02)
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- Synthesis of bryophyte components. 3. New syntheses of Perrottetines E, F and G
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Efficient and expeditious syntheses of the Perrottetines E, F and G (4',5-bis(m-hydroxyphenethyl)diphenyl ether derivatives) are developed, which give rise to these biologically active linear bis(bibenzyl) derivatives on a preparative scale.
- Eicher,Walter
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p. 469 - 473
(2007/10/02)
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