- Synthesis of α-keto aldehydes via selective Cu(i)-catalyzed oxidation of α-hydroxy ketones
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An efficient approach to synthesize α-keto aldehydes was established through selective oxidation of α-hydroxy ketones catalyzed by Cu(i) using oxygen as oxidant. A wide array of α-keto aldehydes was prepared with isolated yields of up to 87%. The potential utilization of this reaction was evaluated by gram-scale reactions and synthetic applications.
- Zheng, Shasha,Smit, Wietse,Spannenberg, Anke,Tin, Sergey,de Vries, Johannes G.
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p. 4639 - 4642
(2022/04/19)
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- Requirements for mammalian carboxylesterase inhibition by substituted ethane-1,2-diones
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Carboxylesterases (CE) are ubiquitous enzymes found in both human and animal tissues and are responsible for the metabolism of xenobiotics. This includes numerous natural products, as well as a many clinically used drugs. Hence, the activity of these agents is likely dependent upon the levels and location of CE expression. We have recently identified benzil is a potent inhibitor of mammalian CEs, and in this study, we have assessed the ability of analogues of this compound to inhibit these enzymes. Three different classes of molecules were assayed: One containing different atoms vicinal to the carbonyl carbon atom and the benzene ring [PhXC(O)C(O)XPh, where X = CH2, CHBr, N, S, or O]; a second containing a panel of alkyl 1,2-diones demonstrating increasing alkyl chain length; and a third consisting of a series of 1-phenyl-2-alkyl-1,2-diones. In general, with the former series of molecules, heteroatoms resulted in either loss of inhibitory potency (when X = N), or conversion of the compounds into substrates for the enzymes (when X = S or O). However, the inclusion of a brominated methylene atom resulted in potent CE inhibition. Subsequent analysis with the alkyl diones [RC(O)C(O)R, where R ranged from CH3 to C8H17] and 1-phenyl-2-alkyl-1,2-diones [PhC(O)C(O)R where R ranged from CH3 to C6H13], demonstrated that the potency of enzyme inhibition directly correlated with the hydrophobicity (c log P) of the molecules. We conclude from these studies that that the inhibitory power of these 1,2-dione derivatives depends primarily upon the hydrophobicity of the R group, but also on the electrophilicity of the carbonyl group.
- Parkinson, Elizabeth I.,Jason Hatfield,Tsurkan, Lyudmila,Hyatt, Janice L.,Edwards, Carol C.,Hicks, Latorya D.,Yan, Bing,Potter, Philip M.
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experimental part
p. 4635 - 4643
(2011/09/19)
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- Chemi- and Bio-luminescence of Coelenterazine Analogues with Phenyl Homologues at the C-2 Position
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A series of phenyl homologues of coelenterazine substituted at the C-2 position were synthesized and their bio- and chemi-luminescence properties were investigated including the measurement of chemiluminescence spectra in various media.The light emitting species of each analogue was found to be a neutral form of a coelenteramide derivative in diethylene glycol dimethyl ether (DGM) containing a trace amount of acetate buffer (pH 5.60), while a monoanion was found only in dimethyl sulfoxide (DMSO) and a dianion was observed in DMSO containing a trace amount of aqueous sodium hydroxide.Based on pseudo first-order reaction kinetics, chemiluminescence rate constants were obtained in DGM containing a trace amount of acetate buffer.Each of the synthetic coelenterazine analogues was incorporated into recombinant apoaequorin to obtain a series of semisynthetic aequorins.Measurements of bioluminescence activities of the aequorins revealed that a benzyl group in the C-2 position was essential for efficient luminescence activity.A two-step incubation procedure was used to determine why some analogues gave less luminescence activity than the benzyl analogue and natural coelenterazine.
- Qi, Chen Feng,Gomi, Yasushiro,Hirano, Takashi,Ohashi, Mamoru,Ohmiya, Yoshihiro,Tsuji, Frederick I.
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p. 1607 - 1612
(2007/10/02)
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