Developing Photoactive Coumarin-Caged N-Hydroxysulfonamides for Generation of Nitroxyl (HNO)
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Authors
Rahman, MS
Bharadwaj, V
Lautaha, AKHS
Sampson, P
Brasch, NE
Seed, AJ
Supervisor
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Journal Article
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MDPI AG
Abstract
Photoactive N-hydroxysulfonamides photocaged with the (6-bromo-7-hydroxycoumarin-4-yl)methyl chromophore have been successfully synthesized, and the mechanisms of photodecomposition investigated for two of the compounds. Upon irradiation up to 97% of a diagnostic marker for (H)NO release, sulfinate was observed for the trifluoromethanesulfonamide system. In the absence of a species that reacts rapidly with (H)NO, (H)NO instead reacts with the carbocation intermediate to ultimately generate (E)-BHC-oxime and (Z)-BHC-oxime. Alternatively, the carbocation intermediate reacts with solvent water to give a diol. Deprotonation of the N(H) proton is required for HNO generation via concerted C-O/N-S bond cleavage, whereas the protonation state of the O(H) does not affect the observed photoproducts. If the N(H) is protonated, C-O bond cleavage to generate the parent N-hydroxysulfonamide will occur, and/or O-N bond cleavage to generate a sulfonamide. The undesired competing O-N bond cleavage pathway increases when the volume percentage of water in acetonitrile/water solvent mixtures is increased.Description
Keywords
HNO, N-hydroxysulfonamide, Piloty’s acid, nitroxyl, photocage, photochemistry, 3402 Inorganic Chemistry, 34 Chemical Sciences, 0304 Medicinal and Biomolecular Chemistry, 0305 Organic Chemistry, 0307 Theoretical and Computational Chemistry, Organic Chemistry, 3404 Medicinal and biomolecular chemistry, 3405 Organic chemistry
Source
Molecules, ISSN: 1420-3049 (Print); 1420-3049 (Online), MDPI AG, 29(16), 3918-. doi: 10.3390/molecules29163918
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© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).