- Asymmetric Total Syntheses of Kopsia Indole Alkaloids
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The asymmetric total syntheses of a group of structurally complex Kopsia alkaloids, (?)-kopsine, (?)-isokopsine, (+)-methyl chanofruticosinate, (?)-fruticosine, and (?)-kopsanone, has been achieved. The key strategies for the construction of the molecular complexity in the targets included an asymmetric Tsuji–Trost rearrangement to set the first quaternary carbon center at C20, an intramolecular cyclopropanation by diazo decomposition to install the second and third quaternary carbon centers at C2 and C7, respectively, and a SmI2-promoted acyloin condensation to assemble the isokopsine core. A radical decarboxylation of an isokopsine-type intermediate results in a thermodynamic partial rearrangement to give N-decarbomethoxyisokopsine and N-decarbomethoxykopsine, two key intermediates for the syntheses of Kopsia alkaloids with different subtype core structures.
- Leng, Lingying,Zhou, Xiaohan,Liao, Qi,Wang, Falu,Song, Hao,Zhang, Dan,Liu, Xiao-Yu,Qin, Yong
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supporting information
p. 3703 - 3707
(2017/03/21)
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- Design, synthesis, and herbicidal activities of novel 2-cyanoacrylates containing isoxazole moieties
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A series of novel 2-cyanoacrylates containing an isoxazole moiety were designed and synthesized. Their structures were characterized by 1H NMR and elemental analysis (or high-resolution mass spectrometry). Their herbicidal activities against four species were evaluated, and the results indicated that some of the title compounds showed excellent herbicidal activities against rape and amaranth pigweed in postemergence treatment even at a dose of 75 g/ha.
- Liu, Yuxiu,Cui, Zhipeng,Liu, Bin,Cai, Baoli,Li, Yonghong,Wang, Qingmin
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experimental part
p. 2685 - 2689
(2011/07/07)
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- Synthesis and evaluation of 2β-oxyimino and alkenylpenicillanic acid sulfone derivatives as β-lactamase inhibitors
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The synthesis and in vitro synergies of 2β-alkenyl and oxyiminopenam sulfone derivatives are described. Most of the compounds synthesized exhibited good inhibitory activities and synergistic antibacterial activities with piperacillin and ceftriaxone, resp
- Cho, Yong Seo,Ha, Young Jin,Kwon, Jin Sun,Pae, Ae Nim,Choi, Kyung Il,Koh, Hun Yeong,Chang, Moon Ho,Yoon, Cheol-Min,Lee, Gwan Sun
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- Pesticidal compounds
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Compounds of the formula: STR1 wherein R1 is hydrogen or alkyl; Q is a linkage group of the formula --CHR2 -- or --CHR3 --CHR4 --where R2 is hydrogen or alkyl, R3 is hydrogen or alkyl, and R4 is hydrogen or alkyl; X is nitrogen or =CH--; and Z is halogen, show insecticidal activity. Also disclosed are the processes for producing the compounds and methods of using them as insecticides.
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