- Diazaborines oxidize slowly with H2O2 but rapidly with peroxynitrite in aqueous buffer
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Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and peroxynitrite (ONOO?) oxidize arylboronic acids to their corresponding phenols. When used in molecular imaging probes and in ROS-responsive molecules, however, simple arylboronic acids struggle to discriminate between H2O2 and ONOO? because of their fast rate of reaction with both ROS. Here, we show that diazaborines (DABs) react slowly with H2O2 but rapidly with peroxynitrite in an aqueous buffer. In addition to their slow reaction with H2O2, the immediate product of DAB oxidation with H2O2 and ONOO? can yield a kinetically trapped CN Z-isomer that slowly equilibrates with its E-isomer. Taken together, our work shows that diazaborines exhibit enhanced kinetic discrimination between H2O2 and ONOO? compared to arylboronic acids, opening up new opportunities for diazaborine-based tools in chemical biology.
- Domaille, Dylan W.,Golzwarden, Julian V. A.,Haggett, Jack G.,Han, Gun Su,Moser, Angela R.,Vyas, Shubham
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supporting information
p. 995 - 999
(2022/02/16)
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- Tuning the exchange dynamics of boronic acid hydrazones and oximes with pH and redox control
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Dynamic bonds continually form and dissociate at equilibrium. Carbonyl compounds with proximal boronic acids, including 2-formylphenylboronic acid (2-FPBA), have been reported to form highly dynamic covalent hydrazone and oxime bonds in physiological conditions, but strategies to tune the dynamics have not yet been reported. Here, we characterize the dynamics of 2-FPBA-derived hydrazones and oximes and account for both the rapid rate of formation (~102-103M?1s?1) and the relatively fast rate of hydrolysis (~10?4s?1) at physiological pH. We further show that these substrates undergo exchange with α-nucleophiles, which can be reversibly paused and restarted with pH control. Finally, we show that oxidation of the arylboronic acid effectively abolishes the rapid dynamics, which slows the forward reaction by more than 30?000 times and increases the hydrolytic half-life from 50 minutes to 6 months at physiological pH. These results set the stage to explore these linkages in dynamic combinatorial libraries, reversible bioconjugation, and self-healing materials.
- Han, Gun Su,Domaille, Dylan W.
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p. 4986 - 4991
(2021/06/16)
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- Preparation method O - alkyl substituted hydroxylamine salt
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The invention relates to a preparation method of N - alkyl substituted hydroxylamine salt, and belongs to fine chemical engineering. Pesticide or bulk pharmaceutical chemicals technical field. The present invention reacts with the N - alkyl of the oxime with an inorganic salt of hydroxylamine to give N - alkyl-substituted hydroxylamine salt and oxime. The invention provides an efficient and environment-friendly method for preparing N - alkyl substituted hydroxylamine salt, and simultaneously, an N - alkyl substituted hydroxylamine salt is prepared, and the oxime can be re-prepared to form N - alkylate of oxime so as to realize the material circulation. No equivalent acid is used in the reaction process. Alkali neutralization, avoided the current method to use a large amount of acid, alkali and produce inorganic salt solid waste shortcoming, environmental protection more. The preparation method is mild in reaction condition, and the defects of high pollution and high energy consumption of the traditional process are overcome. In-flight R1 , R2 What is R is as claimed in the claims and the description.
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Paragraph 0098; 0102-0103
(2021/11/14)
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- Synthesis of 4-(alkoxyamino)chroman-2-ones via 6-exo-trig cyclization of carbon-centered radicals into oxime ethers
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[Figure not available: see fulltext.] 4-(Alkoxyamino)chroman-2-ones were synthesized via a 6-exo-trig cyclization of alkyl radicals obtained from α-bromoesters containing an oxime ether group. In the case of secondary bromides, the best results were achie
- Bejarano, Carlos A.,Díaz, John E.,Loaiza, Alix E.
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p. 177 - 182
(2016/07/28)
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- Screening of ligands for the Ullmann synthesis of electron-rich diaryl ethers
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In the search for new ligands for the Ullmann diaryl ether synthesis, permitting the coupling of electron-rich aryl bromides at relatively low temperatures, 56 structurally diverse multidentate ligands were screened in a model system that uses copper iodide in acetonitrile with potassium phosphate as the base. The ligands differed largely in their performance, but no privileged structural class could be identified.
- Otto, Nicola,Opatz, Till
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supporting information; experimental part
p. 1105 - 1111
(2012/09/07)
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- Boron Chelates of Salicylaldoxime and Derivatives
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Formation and structure of boron chelates of salicylaldoxime are studied with O-alkyloximes and O-acyloximes of salicylaldehyde.The six-membered ring chelates thus obtained are synthesized also by alkylation resp. acylation of the preformed salicylaldoxime boron chelates.Thermolysis of the difluoroboron or diphenylboron chelates gives fluoroboronic resp. phenylboronic acid derivatives of salicylaldoxime that are isolated as dimeric compounds. - Keywords: Boron chelates; Salicylaldoxime boronates; Salicylaldoxime, O-alkyloxime and O-acyloxime; 2-Aminobezaldoxim
- Kliegel, Wolfgang,Nanninga, Dierk
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p. 465 - 484
(2007/10/02)
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