- Rhodium-Catalyzed Generation of Anhydrous Hydrogen Iodide: An Effective Method for the Preparation of Iodoalkanes
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The preparation of anhydrous hydrogen iodide directly from molecular hydrogen and iodine using a rhodium catalyst is reported for the first time. The anhydrous hydrogen iodide generated was proven to be highly active in the transformations of alkenes, phenyl aldehydes, alcohols, and cyclic ethers to the corresponding iodoalkanes. Therefore, the present methodology not only has provided convenient access to anhydrous hydrogen iodide but also offers a practical preparation method for various iodoalkanes in excellent atom economy.
- Zeng, Chaoyuan,Shen, Guoli,Yang, Fan,Chen, Jingchao,Zhang, Xuexin,Gu, Cuiping,Zhou, Yongyun,Fan, Baomin
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supporting information
p. 6859 - 6862
(2018/10/25)
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- 1,3-Dimethoxy-5-methylene-1,3-cyclohexadiene Compounds with Leaving Groups at C6: Generation, Solvolytic Reactivity, and Their Importance in the Photochemistry of 3,5-Dimethoxybenzyl Derivatives
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The photochemistry of 3,5-dimethoxybenzyl compounds with the leaving groups acetate (1a), chloride (1b), bromide (1c), iodide (1d), diethyl phosphate (1e), and trimethylamine (1f), as the chloride, was examined by both product studies and flash photolysis. The isomeric triene, 5-methylene-1,3-cyclohexadiene derivative was observed for the acetate (2a), diethyl phosphate (2e) and trimethylammonium chloride (2f). The solvolysis of these derivatives, 2, was examined in alcohol solvents and the rate correlation with YOTS values gave m = 0.47 (2a) and 0.63 (2e), suggesting SN1 reactivity but with an early transition state. Quantum yields for formation of 2a and 2e indicated that these trienes play only a minor role (~16%) in the overall photochemistry of the corresponding arylmethyl substrates.
- DeCosta,Howell,Pincock,Pincock,Rifai
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p. 4698 - 4705
(2007/10/03)
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- Synthesis of (±)-Hiburipyranone, a Cytotoxic Metabolite of Marine Sponge Mycale adhaerens
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Hiburipyranone, a cytotoxic metabolite of the marine sponge, Mycale adhaerens, was synthesized as a racemate.
- Uchida, Kanako,Watanabe, Hidenori,Mori, Kenji
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p. 1564 - 1567
(2007/10/03)
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- Synthesis and quantitative structure-activity relationship of a novel series of small conductance Ca2+-activated K+ channel blockers related to dequalinium
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The synthesis, pharmacological testing, and quantitative structure- activity relationship studies of a novel series of bisquinolinium small conductance Ca2+-activated K+ channel blockers (23) related to dequalinium are described. In this series, two quinolinium rings are linked via the 4- position to an α,ω-diamino alkylene chain and the ring N atom is quaternized with a methyl or benzyl group. The exocyclic N atom can be replaced by 0, S, or CH2 but with some loss of potency. The quinoline groups do not have to be quaternized for blocking activity, as long as they are basic enough to be protonated at the site of action. For the quaternary compounds, there is considerable steric tolerance for the group R attached to the ring N atom of the quinoline; a benzyl group gave the optimum potency in this series. Moreover, and in contrast to previously reported results for dequalinium analogues, there is no correlation of activity with N1 charge or E(HOMO). On the other hand, a good correlation was obtained between the blocking potency of the compounds and E(LUMO) [pEMR = 1.16(±0.26)E(LUMO) + 5.33(±1.29) (n = 11, r = 0.83, s = 0.243)]. It has been possible to combine this equation with the previously reported E(LUMO) correlation for a series of dequalinium analogues to include all the compounds of both series [pEMR = 1.17(±0.15)E(LUMO) + 5.33(±0.76) (n = 24, r = 0.85, s = 0.249)]. A possible physical meaning for the E(LUMO) correlation based upon the principle of maximum hardness is discussed.
- Galanakis,Davis,Ganellin,Dunn
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p. 359 - 370
(2007/10/03)
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- Antitumor agents. 120. New 4-substituted benzylamine and benzyl ether derivatives of 4'-O-demethylepipodophyollotoxin as potent inhibitors of human DNA topoisomerase II
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A number of new 4'-O-demethylepipodophyllotoxin derivatives possessing various 4β-N- or 4β-O-benzyl groups have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The 4β-N-benzyl derivatives 9-22 are, in general, as active or more active than etoposide (1). The most active compounds are 14, 16, and 17, which are more than 2-fold more potent than 1. The results indicated that a basic unsubstituted 4β-benzylamino moiety is structurally required for the enhanced activity. Replacement of the benzyl nitrogen with oxygen gave compounds (23 and 24) which are inactive. The ability of these compounds to inhibit human DNA topoisomerase II and to cause protein-linked DNA breakage appears to have no direct correlation with cytotoxicity in KB cells.
- Zhou,Wang,Chang,Chen,Cheng,Lee
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p. 3346 - 3350
(2007/10/02)
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