2446-50-6Relevant academic research and scientific papers
Temperature-Dependent Acid Dissociation Constants (Ka, ΔHa, ΔSa) for some C-Aryl Hydroxamic Acids: The Influence of C and N Substituents on Hydroxamate Anion Solvation in Aqueous Solution
Brink, Christina Poth,Fish, L. Lynne,Crumbliss, Alvin L.
, p. 2277 - 2281 (1985)
The acid dissociation constants (Ka) of a series of substituted N-methylbenzohydroxamic acids, 4-XC6H4C(O)N(OH)CH3 (X = H, CH3O, CH3, NO2) and 4-methoxybenzohydroxamic acid, 4-CH3OC6H4C(O)N(OH)H, have been determinated in aqueous solution (I =
Late-Stage Photoredox C-H Amidation of N-Unprotected Indole Derivatives: Access to N-(Indol-2-yl)amides
Weng, Yue,Ding, Bo,Liu, Yunqing,Song, Chunlan,Chan, Lo-Ying,Chiang, Chien-Wei
supporting information, p. 2710 - 2714 (2021/05/05)
The late-stage functionalization of N-unprotected indoles can be useful for modifying low-molecular-weight drugs and bioactive peptides. Whereas indole carboxamides are valuable in pharmaceutical applications, the preparation N-(indol-2-yl)amides with similar structures continues to be challenging. Herein we report on visible-light-induced late-stage photoredox C-H amidation with N-unprotected indoles and tryptophan-containing peptides, leading to the formation of N-(indol-2-yl)amide derivatives. N-Unprotected indoles and aryloxyamides that contain an electron-withdrawing group could be coupled directly to eosin Y as the photocatalyst by irradiation with a green light-emitting diode at room temperature. Mechanistic studies and density functional theory calculations indicate that the transformation might proceed through the oxidative C-H functionalization of indole with a PS? to PS?- cycle. This protocol provides a new toolkit for the late-stage modification labeling and peptide-drug conjugation of N-unprotected indole derivatives.
Access to Cyanoimines Enabled by Dual Photoredox/Copper-Catalyzed Cyanation of O-Acyl Oximes
Wei, Ziyan,Yu, Shouyun,Zhang, Ai Hua,Zhang, Hao
supporting information, p. 7315 - 7320 (2020/10/02)
An efficient strategy for the synthesis of pharmaceutically important and synthetically useful cyanoimines, as well as cyanamides, has been described. This strategy is enabled by dual photoredox/copper-catalyzed cyanation of O-acyl oximes or O-acyl hydroxamides. This state of the art protocol for cyanoimines and cyanamides features readily available starting materials, mild reaction conditions, good functional group tolerance, and operational simplicity. The resultant cyanoimines can be transformed into structurally diverse and functionally important N-containing heterocycles.
Direct and Selective 3-Amidation of Indoles Using Electrophilic N-[(Benzenesulfonyl)oxy]amides
Ortiz, Gerardo X.,Hemric, Brett N.,Wang, Qiu
supporting information, p. 1314 - 1317 (2017/03/23)
Selective C-H amidation of 1H-indoles at the C3 position is reported as a direct entry to biologically important 3-aminoindoles. This transformation is achieved using novel N-[(benzenesulfonyl)oxy]amides as electrophilic nitrogen agents in the presence of ZnCl2. Interestingly, analogous reactions in the absence of ZnCl2 resulted in the formation of indole aminal products.
Oxidative cleavage of hydroxamic acid promoted by sodium periodate
Yuan, Changchun,Du, Biao,Xun, Miao-Miao,Liu, Bo
, p. 3622 - 3628 (2017/06/13)
A series of hydroxamic acids, involving aliphatic, aromatic and cyclic substrates, were transformed to the corresponding carboxylic acids through NaIO4-mediated oxidative cleavage in mild conditions. Esterification of these acids with TMSCHN2 could result in formation of the corresponding methyl ester. This methodology makes good compensation for the existing methods transforming amides to esters. Our results also pave the way to harness hydroxamic acids as useful synthetic building blocks.
Monohydroxamic acids and bridging dihydroxamic acids as chelators to ruthenium(iii) and as nitric oxide donors: Syntheses, speciation studies and nitric oxide releasing investigation
Griffith, Darren,Krot, Krystyna,Comiskey, Jedd,Nolan, Kevin B.,Marmion, Celine J.
, p. 137 - 147 (2008/04/13)
The synthesis and spectroscopic characterisation of novel mononuclear RuIII(edta)(hydroxamato) complexes of general formula [Ru(H 2edta)(monoha)] (where monoha = 3- or 4-NH2, 2-, 3- or 4-Cl and 3-Me-phenylhydroxamato), as well as the first example of a Ru III-N-aryl aromatic hydroxamate, [Ru(H2edta)(N-Me-bha)] ·H2O (N-Me-bha = N-methylbenzohydroxamato) are reported. Three dinuclear RuIII complexes with bridging dihydroxamato ligands of general formula [{Ru(H2edta)}2(μ-diha)] where diha = 2,6-pyridinedihydroxamato and 1,3- or 1,4-benzodihydroxamato, the first of their kind with RuIII, are also described. The speciation of all of these systems (with the exception of the Ru-1,4-benzodihydroxamic acid and Ru-N-methylbenzohydroxamic systems) in aqueous solution was investigated. We previously proposed that nitrosyl abstraction from hydroxamic acids by Ru III involves initial formation of RuIII-hydroxamates. Yet, until now, no data on the rate of nitric oxide (NO) release from hydroxamic acids has been published. We now describe a UV-VIS spectroscopic study, where we monitored the decrease in the ligand-to-metal charge-transfer band of a series of RuIII-monohydroxamates with time, with a view to gaining an insight into the NO-releasing properties of hydroxamic acids. The Royal Society of Chemistry.
Determination of pKa's of hydroxamic acids by nucleophilic substitution reaction
Shrivastava, Ashish,Ghosh, Kallol K.,Dubey
, p. 1630 - 1634 (2008/09/19)
Acid dissociation constant (pKa) of some para-substituted benzohydroxamic, 4-XC6H4CONHOH, and N-methyl para-substituted benzohydroxamic acids, 4- XC6H4CON(OH) CH3, where X = H, CH3, CH3O, NO2, Cl, have been determined spectrophotometrically by nucleophilic substitution reactions of p-nitrophenyl acetate with hydroxamate ions at 27± 0.1°C. All reactions in this study follow pseudo-first order kinetics under condition of excess nucleophile. Good correlation has been observed between pKa and substitutent constants pointing out the validity of the Hammett equation. The kinetics results have been discussed on the basis of pKa and α-effect of hydroxamic acids.
Protective solutions for organs
-
, (2008/06/13)
Described is a protective solution for avoiding ischemic, storage or ischemia/reperfusion to organs, or to isolated cell systems, or to tissue components after perfusion, surgery, transplantation, or cryopreservation and subsequent reperfusion, which contains alkali ions, and if need be also alkaline earth ions as the electrolyte, a buffer e.g. on a histidine derivation basis, as well as a polyol and/or a saccharide, has an osmolarity of about 290 mosm/l to about 350 mosm/l, as well as a pH value of about 6.8 to about 7.4, and to which hydroxamic acid, and/or one or more hydroxamic acid derivatives are added.
A Facile Preparation of N-(Isopropoxyalkyl) Amides by Generation and Trapping of N-Acyliminium Ions from Ionization-Rearrangement Reactions of N-Triflyloxy Amides
Hoffman, Robert V.,Nayyar, Naresh K.
, p. 3530 - 3539 (2007/10/02)
A series of hydroxamic acids were converted to N-triflyloxy amides which were heated in 2-propanol to give N-(1-isopropoxyalkyl) amides in high yields.The method is simple, direct, and extremely tolerant of structural diversity both in the N-acyl group, a
Polar ligand adsorption controls semiconductor surface potentials
Bruening,Moons,Yaron-Marcovich,Cahen,Libman,Shanzer
, p. 2972 - 2977 (2007/10/02)
Controlled surface modification of CdTe single crystals and CdTe and CulnSe2 solar cell quality thin films was achieved by chemisorption of a series of organic ligands with varying dipole moments. Contact potential difference measurements in air showed that adsorption of benzoic or hydroxamic acid derivatives on the thin films or crystals changes the semiconductors' electron affinity without significantly affecting band bending. The magnitude and direction of surface potential changes, which reach 670 mV between extreme modifications, correlate with the ligands' dipole moments. Ligand dipole moments were controlled by varying the substituents of the ligand. Quantitative Fourier transform infrared (FTIR) spectroscopy showed that benzoic acid surface coverage is about one monolayer. Finally, FTIR spectral analysis showed that the benzoic acid derivatives adsorb via coordination to Cd on CdTe and that hydroxamic acids bind to Cd on CdTe and to In on CuInSe2. These phenomena occur in several systems (two semiconductor compounds, two types of binding groups, and two types of surface morphologies were examined) and may prove useful in band edge engineering.
