24618-17-5Relevant academic research and scientific papers
Thermodynamic and structural study of complexation of phenylboronic acid with salicylhydroxamic acid and related ligands
Martínez-Aguirre, Mayte A.,Flores-Alamo, Marcos,Yatsimirsky, Anatoly K.
, (2018)
Stability constants of boronate complexes with a highly efficient bioconjugation ligand salicylhydroxamic acid, its derivatives and some structurally related compounds were determined by potentiometric and spectroscopic titrations at variable pH allowing one to obtain detailed stability – pH profiles and to identify the optimum pH for complexation with each ligand. The N,O-binding of salicylhydroxamic acid via condensation of boronic acid with phenolic OH and hydroxamic NH groups was established by crystal structure determination of isolated complexes with phenylboronic and 4-nitrophenylboronic acids. Although this type of binding is impossible for N-methylated salicylhydroxamic acid it still forms stable boronate complexes supposedly involving unusual 7-membered –O-B-O- cycle supported by 1H NMR studies. Hydroxamic acids lacking ortho-OH group and salicyloyl hydrazide form less stable boronate complexes, which nevertheless possess stabilities similar to those of catechole complexes and may be useful for conjugation applications. In contrast to other ligands, which form tetrahedral anionic complexes, salicylamidoxime forms tetrahedral, but neutral boronate complex with high stability in weakly acid solutions. The highest affinity in neutral and acid solutions surpassing that of salicylhydroxamic acid is observed with 2,6-dihydroxybenzhydroxamic acid (Kobs?=?5.2?×?104 at pH?7.4). Fairly stable mono- and bisboronate complexes are formed with 2,5-dihydroxy-1,4-benzdihydroxamic acid, which also possesses intense fluorescence and may serve as a boronic acid sensor with detection limit 4?μM. Results presented in this study provide quantitative basis for rational applications of hydroxamic acid derivatives in bioconjugation and sensing.
Benzohydroxamic acids as potent and selective anti-HCV agents
Kozlov, Maxim V.,Kleymenova, Alla A.,Romanova, Lyudmila I.,Konduktorov, Konstantin A.,Smirnova, Olga A.,Prasolov, Vladimir S.,Kochetkov, Sergey N.
supporting information, p. 5936 - 5940 (2013/10/22)
A diverse collection of 40 derivatives of benzohydroxamic acid (BHAs) of various structural groups were synthesized and tested against hepatitis C virus (HCV) in full-genome replicon assay. Some of these compounds demonstrated an exceptional activity, suppressing viral replication at sub-micromolar concentrations. The compounds were inactive against key viral enzymes NS3, and NS5B in vitro assays, suggesting host cell inhibition target(s). The testing results were consistent with metal coordination by the BHAs hydroxamic group in complex with a target(s). Remarkably, this class of compounds did not suppress poliomyelitis virus (PV) propagation in RD cells indicating a specific antiviral activity of BHAs against HCV.
Intramolecular General Base Catalysis and the Rate-determining Step in the Nucleophilic Cleavage of Ionized Phenyl Salicylate with Primary and Secondary Amines
Khan, Mohammad Niyaz
, p. 199 - 208 (2007/10/02)
The nucleophilic second-order rate constants for the reactions of ionized phenyl salicylate (PS-) with primary and secondary amines have revealed Broensted plots of slopes βnuc1 = 0.52+/-0.06 and βnuc2 = 0.27+/-0.05, respectively.The suggested stepwise reaction mechanism involves the intramolecular proton transfer from cationic nitrogen to the anionic phenolic oxygen to form the monoanionic tetrahedral addition intermediate as the rate-determining step.The low value of βnuc2 is attributed to the extensive of proton transfer in the late transition state while the large value of βnuc1 is ascribed to the proton transfer in the early transition state of the rate-determining step.However, these low and high values of βnuc2 and βnuc1, respectively, are also compatible with the occurence of respective early and late transition states in the rate-determining step involving concerted intramolecular general base-catalysed nucleophilic attack at the carbonyl carbon of PS-.Significantly large positive deviations from Broensted plots have been observed for the reactivities of α-nucleophiles toward PS-.Monoprotonated ethane-1,2-diamine is ca. 20-fold more reactive than would be expected from its basicity, and this is attributed to the occurence of the intramolecular general acid catalysis.The reactions of PS- with hydroxylamine and N-methylhydroxylamine involve ca. >/=70 percent aminolysis and -.
