546-88-3Relevant academic research and scientific papers
N-O Bond Fission as the Rate-Determining Step in the Aqueous Conversion of N-Peptidyl-O-(p-nitrobenzoyl)hydroxylamines to p-Nitrobenzoic Acid and Peptidylhydroxamic Acids
Demuth, Hans-Ulrich,Fischer, G.,Barth, A.,Schowen, R. L.
, p. 5880 - 5883 (1989)
N-Acetyl-, N-alanyl-alanyl-, N-alanyl-prolyl-, and N-Boc-alanyl-prolyl-O-(p-nitrobenzoyl) hydroxylamines, compounds that are mechanism-based irreversible inactivators of some proteolytic enzymes, are degraded in aqueous buffers at neutral pH to p-nitrobenzoic acid and either the corresponding N-acylhydroxamic acid or products of its further degradation such as the diketopiperazine.At neutral pH, the reactants exist as the monoanion, as a result of the acidity of the -CO-NH-O- linkage.The p-nitrobenzoic acid formed in a mixture of 50percent H2(18)O and 50percent H2(16)O contains less than 2percent (18)O, which shows that nucleophilic attack of water at the ester carbonyl is not occuring in the degradation.The decomposition of the N-alanyl-prolyl derivative, labeled with (15)N at the N-O nitrogen, exhibits a kinetic isotope effect k14/k15 = 1.092 +/- 0.056, suggesting that N-O fission is occuring in the rate-determining step of the degradation.Kinetic solvent isotope effects of 1.02-1.15 are inconsistent with an expectation of factors around 2 or greater for spontaneous hydrolysis of the ester linkage.All derivatives have ΔH* = 24-27 kcal/mol and ΔS* = +4-7 eu, consistent with unimolecular fission of the substrate N-O to generate p-nitrobenzoate ion and the acyl nitrene.The nitrene must suffer nucleophilic attack at nitrogen very rapidly, producing the hydroxamic acid as the initial product.In the peptide derivatives, further reaction to the cyclized products results.
Investigation of structural effects and behaviour of Pseudomonas aeruginosa amidase encapsulated in reversed micelles
Fragoso, Ana,Pacheco, Rita,Karmali, Amin
, p. 264 - 272 (2012)
The acetohydroxamic acid synthesis reaction was studied using whole cells, cell-free extract and purified amidase from the strains of Pseudomonas aeruginosa L10 and AI3 entrapped in a reverse micelles system composed of cationic surfactant tetradecyltrimethyl ammonium bromide. The specific activity of amidase, yield of synthesis and storage stability were determined for the reversed micellar system as well as for free amidase in conventional buffer medium. The results have revealed that amidase solutions in the reverse micelles system exhibited a substantial increase in specific activity, yield of synthesis and storage stability. In fact, whole cells from P. aeruginosa L10 and AI3 in reverse micellar medium revealed an increase in specific activity of 9.3- and 13.9-fold, respectively, relatively to the buffer medium. Yields of approximately 92% and 66% of acetohydroxamic acid synthesis were obtained for encapsulated cell free extract from P. aeruginosa L10 and AI3, respectively. On the other hand, the half-life values obtained for the amidase solutions encapsulated in reverse micelles were overall higher than that obtained for the free amidase solution in buffer medium. Half-life values obtained for encapsulated purified amidase from P. aeruginosa strain L10 and encapsulated cell-free extract from P. aeruginosa strain AI3 were of 17.0 and 26.0 days, respectively. As far as the different sources biocatalyst are concerned, the data presented in this work has revealed that the best results, in both storage stability and biocatalytic efficiency, were obtained when encapsulated cell-free extract from P. aeruginosa strain AI3 at w0 of 10 were used. Conformational changes occurring upon encapsulation of both strains enzymes in reverse micelles of TTAB in heptane/octanol were additionally identified by FTIR spectroscopy which clarified the biocatalysts performances.
Activation and Orientation by Receptor-Substrate Binding. The Case of Acyl Transfer from O-Acetylhydroxylamine
Lehn, Jean-Marie,Nishiya, Takako
, p. 215 - 218 (1987)
The strong binding ability of the receptor molecule 1 induces complexation of O-acetylhydroxylamine and of hydroxylamine in their protonated forms; as a result, subsequent reaction of bound CH3COONH3+ becomes fast and selective, giving only acetic acid with a rate enhancement by a factor of about 30.
Synthetic method for acetylhydroxylamine
-
Paragraph 0026-0029, (2021/08/06)
The invention provides a synthesis method for acetylhydroxylamine. The method adopts a two-step method to synthesize acetylhydroxylamine, a first micro-channel reactor and a second micro-channel reactor are used for replacing a traditional reaction bottle. The complete dissolution concentration of hydroxylamine hydrochloride in water is 42%, and 30% sodium hydroxide solution is prepared. The hydroxylamine hydrochloride aqueous solution and the sodium hydroxide aqueous solution are simultaneously fed into a first micro-channel reactor by using different metering pumps to react, the reaction temperature is controlled to be 20-25 DEG C, reaction liquid is collected, the obtained reaction liquid and ethyl acetate are simultaneously fed into a second micro-channel reactor to react, the reaction temperature is controlled to be 30-35 DEG C, and after the reaction is finished, distilling is conducted to obtain acetylhydroxylamine. The synthetic method of acetylhydroxylamine is improved, the raw materials are simple, the reaction is easy to control, the process is simple, waste is few, the total yield can reach 98%, and the synthetic method is suitable for industrial production.
Alternating Current Electrolysis as Efficient Tool for the Direct Electrochemical Oxidation of Hydroxamic Acids for Acyl Nitroso Diels–Alder Reactions
F?hrmann, Jan,Hilt, Gerhard
supporting information, p. 20313 - 20317 (2021/08/12)
The acyl nitroso Diels–Alder reaction of 1,3-dienes with electrochemically oxidised hydroxamic acids is described. By using alternating current electrolysis, their typical electro-induced decomposition could be suppressed in favour of the 1,2-oxazine cycloaddition products. The reaction was optimised using Design of Experiments (DoE) and a sensitivity test was conducted. A mixture of triethylamine/hexafluoroisopropanol served as supporting electrolyte in dichloromethane, thus giving products of high purity after evaporation of the volatiles without further purification. The optimised reaction conditions were applied to various 1,3-dienes and hydroxamic acids, giving up to 96 % isolated yield.
Hydroxamates as a potent skeleton for the development of metallo-β-lactamase inhibitors
Chen, Cheng,Chigan, Jia-Zhu,Ding, Huan-Huan,Li, Jia-Qi,Liu, Lu,Xu, Yin-Sui,Yang, Ke-Wu
, (2021/12/14)
Bacterial resistance caused by metallo-β-lactamases (MβLs) has become an emerging public health threat, and the development of MβLs inhibitor is an effective way to overcome the resistance. In this study, thirteen novel O-aryloxycarbonyl hydroxamates were constructed and assayed against MβLs. The obtained molecules specifically inhibited imipenemase-1 (IMP-1) and New Delhi metallo-β-lactamase-1, exhibiting an IC50 value in the range of 0.10–18.42 and 0.23–22.33?μM, respectively. The hydroxamate 5 was found to be the most potent inhibitor, with an IC50 of 0.1 and 0.23?μM using meropenem and cefazolin as substrates. ICP-MS analysis showed that 5 did not coordinate to the Zn(II) ions at the active site of IMP-1, while the rapid dilution, thermal shift and MALDI-TOF assays revealed that the hydroxamate formed a covalent bond with the enzyme. Cytotoxicity assays indicated that the hydroxamates have low toxicity in MCF-7 cells. This work provided a potent scaffold for the development of MβLs inhibitors.
Novel fluorinated 7-hydroxycoumarin derivatives containing an oxime ether moiety: Design, synthesis, crystal structure and biological evaluation
Dai, Peng,Jiao, Jian,Wang, Qing-Qing,Zhang, Shu-Guang,Zhang, Wei-Hua
, (2021/06/28)
A series of fluorinated 7-hydroxycoumarin derivatives containing an oxime ether moiety have been designed, synthesized and evaluated for their antifungal activity. All the target compounds were determined by1H-NMR,13C-NMR, FTIR and HR-MS spectra. The single-crystal structures of compounds 4e, 4h, 5h and 6c were further confirmed using X-ray diffraction. The antifungal activities against Botrytis cinerea (B. cinerea), Alternaria solani (A. solani), Gibberella zeae (G. zeae), Rhizoctorzia solani (R. solani), Colletotrichum orbiculare (C. orbiculare) and Alternaria alternata (A. alternata) were evaluated in vitro. The preliminary bioassays showed that some of the designed compounds displayed the promising antifungal activities against the above tested fungi. Strikingly, the target compounds 5f and 6h exhibited outstanding antifungal activity against B. cinerea at 100 μg/mL, with the corresponding inhibition rates reached 90.1 and 85.0%, which were better than the positive control Osthole (83.6%) and Azoxystrobin (46.5%). The compound 5f was identified as the promising fungicide candidate against B. cinerea with the EC50 values of 5.75 μg/mL, which was obviously better than Osthole (33.20 μg/mL) and Azoxystrobin (64.95 μg/mL). Meanwhile, the compound 5f showed remarkable antifungal activities against R. solani with the EC50 values of 28.96 μg/mL, which was better than Osthole (67.18 μg/mL) and equivalent to Azoxystrobin (21.34 μg/mL). The results provide a significant foundation for the search of novel fluorinated 7-hydroxycoumarin derivatives with good antifungal activity.
Co(III)-Catalyzed C-H Amidation of Nitrogen-Containing Heterocycles with Dioxazolones under Mild Conditions
Dhiman, Ankit Kumar,Thakur, Ankita,Kumar, Inder,Kumar, Rakesh,Sharma, Upendra
, p. 9244 - 9254 (2020/08/14)
A cobalt(III)-catalyzed C-8 selective C-H amidation of quinoline N-oxide using dioxazolone as an amidating reagent under mild conditions is disclosed. The reaction proceeds efficiently with excellent functional group compatibility. The utility of the current method is demonstrated by gram scale synthesis of C-8 amide quinoline N-oxide and by converting this amidated product into functionalized quinolines. Furthermore, the developed catalytic method is also applicable for C-7 amidation of N-pyrimidylindolines and ortho-amidation of benzamides.
Rhodium(III)-catalyzed C4-amidation of indole-oximes with dioxazolones: Via C-H activation
Deng, Ke-Zuan,Fu, Xiao-Pan,Ji, Ya-Fei,Tang, Shi-Biao,Wu, Gao-Rong,Xia, Cheng-Cai,Yang, Jin-Yue,Zhang, Li-Li
supporting information, p. 7922 - 7931 (2020/11/02)
A novel method for the Rh(III)-catalyzed oxime-directed C-H amidation of indoles with dioxazolones has been developed. This strategy provides an exclusive site selectivity and the directing group can be easily removed. This transformation features a wide substrate scope, good functional group tolerance and excellent yields, and may serve as a significant tool to construct structurally diverse indole derivatives for the screening of potential pharmaceuticals in the future. This journal is
Synthesis of benzothiadiazine-1-oxides by rhodium-catalyzed C-H amidation/cyclization
Bolm, Carsten,Kong, Deshen,Ma, Ding,Shi, Peng,Tu, Yongliang,Wang, Chenyang
supporting information, p. 8842 - 8845 (2020/11/30)
A rhodium-catalyzed C-H amidation/cyclization sequence provides benzothiadiazine-1-oxides from sulfoximines and 1,4,2-dioxazol-5-ones in good yields. The reaction is characterized by a high functional group tolerance and, in contrast to most previous transformations of this type, is well-suited for S-alkyl-S-arylsubstituted sulfoximines.
