从机理的角度出发,研究了异羟肟酸释放出具有多种生物学特性的无机小分子硝基氧(HNO)的氧化剂依赖性。实际上,在生理条件下异羟肟酸氧化的确切机理以及中间体的直接或间接表征仍然难以捉摸。在这项工作中,通过1 H NMR,MS,EPR和UV-vis技术监测了在生理pH(7.4)下用K 3 [Fe III(CN)6 ]对异烟酸酯,烟酸酯和吡嗪酮异羟肟酸的分子间氧化反应。。虽然nitrosocarbonyl(二)吖嗪中间体,(二)AZ-C(O)-NO,可以是先验设想,它实际上对应Ñ,识别出的O-二(二)叠氮酰基羟胺(AzC(O)NHOC(O)Az)和HNO,第一个通过1 H NMR,第二个基于EPR和UV-vis实验,使用[2-(4 -羧基苯基)-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物](cPTIO)自旋阱。不稳定的N,O-二(二)叠氮酰基羟胺中间体在水性缓冲介质中的分解显示产生相应的羧
Biotransformation of nicotinamide to nicotinyl hydroxamic acid at bench scale by amidase acyl transfer activity of Pseudomonas putida BR-1
摘要:
Acyl transfer activity of amidase of Pseudomonas putida BR-1 has been explored for the conversion of N-substituted aromatic amide (nicotinamide) and hydroxylamine to nicotinyl hydroxamic acid. Nicotinyl hydroxamic acid is an important pharmaceutical compound with enormous biomedical applications. P. putida BR-1 produces maximum amidase acyl transfer activity 138 U/mg dcm at 50 degrees C, with highest conversion (95%) of nicotinamide to nicotinyl hydroxamic acid. A bioprocess was developed for production of nicotinyl hydroxamic acid in batch reaction (final volume 1 L) by adding 200mM nicotinamide and 1000 mM of hydroxylamine in 100 mM sodium phosphate buffer (pH 7.5) at 50 degrees C, using 20 U/ml acyl transfer activity resting cells of P. putida BR-1 in reaction mixture. From 1 L reaction mixture 16 g of nicotinyl hydroxamic acid was recovered with 32 g/L/h volumetric productivity. The amidase acyl transfer activity of P. putida BR-1 and the process developed in the present study are of industrial significance for the enzyme mediated production of nicotinyl hydroxamic acid. (C) 2014 Elsevier B.V. All rights reserved.
Kinetic Investigation of Micellar Promoted Pyridine based Oximate and Hydroxamate Catalysis on Phosphotriester Pesticides
作者:Hitesh K. Dewangan、Rekha Nagwanshi、Kallol K. Ghosh、Manmohan L. Satnami
DOI:10.1007/s10562-016-1912-5
日期:2017.2
nucleophiles toward the electrophilic center of P=O and P=S bond of phosphate ester shows prominent effect in the presence of cetyltrimethylammoniumbromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB) micelles than aqueous media. The adjacent lone pair of electron in nitrogen atom on the nucleophile moiety of 2-PyOx and 2-PyHA helps to augment the reactivity compared to presence in remote
Iron(III) Tris(pyridinehydroxamate)s and Related Nickel(II) and Zinc(II) Complexes: Potential Platforms for the Design of Novel Heterodimetallic Supramolecular Assemblies
作者:Clodagh Mulcahy、Krystyna A. Krot、Darren M. Griffith、Kyrill Yu. Suponitsky、Zoya A. Starikova、Celine J. Marmion
Photoinduced one-pot synthesis of hydroxamic acids from aldehydes through in-situ generated silver nanoclusters
作者:Yasser M. A. Mohamed、Yasser A. Attia、Eirik Johansson Solum
DOI:10.1007/s11164-018-3549-z
日期:2018.12
Hydroxamic acids have attracted significant attention due to their widespread use in applied chemistry. In this report, a modified Angeli–Rimini method has been achieved via the visible light-mediated catalytic transformation of a variety of heterocyclic, aromatic and aliphatic aldehydes 1a–j to their corresponding hydroxamic acids 2a–j in 81–93% yield. The unique ability of vitamin K3 as a photoredox
异羟肟酸由于在应用化学中的广泛应用而引起了极大的关注。在本报告中,通过可见光介导的各种杂环,芳族和脂肪族醛1a–j到其相应的异羟肟酸2a–j的可见光催化转化,实现了改良的Angeli–Rimini方法,产率为81–93%。已经研究了维生素K 3作为光氧化还原催化剂的独特能力,以加速全新反应机制的发展并能够构建具有挑战性的碳氮键。首次表明维生素K 3和醛是快速原位还原Ag +的主要原因离子进入具有2.87 eV带隙能量且尺寸小于2 nm的催化光致发光Ag纳米簇。已经提出了该反应的机理,并得到了紫外-可见,TEM,ESI / MS,FT-IR,1 H NMR和13 C NMR分析的支持。所研究的方法利用了容易获得的试剂,并以高收率生产了异羟肟酸,而没有形成副产物,使其简单,实用且具有成本效益。
An Experimental and Computational Approach to Understanding the Reactions of Acyl Nitroso Compounds in [4 + 2] Cycloadditions
作者:Duangduan Chaiyaveij、Andrei S. Batsanov、Mark A. Fox、Todd B. Marder、Andrew Whiting
DOI:10.1021/acs.joc.5b01470
日期:2015.10.2
Catalytic aerobic oxidation of phenyl hydroxycarbamate 1 and 1-hydroxy-3-phenylurea 2 using CuCl2 and 2-ethyl-2-oxazoline in methanol gave acyl nitroso species in situ, which were trapped in nitroso-Diels–Alder (NDA) reactions with various dienes to afford the corresponding cycloadducts in high yields (90–98%). Competing ene products were also present for dienes containing both alkene π-bonds and allylic
Cephalosporin antibiotics represented by the formula ##STR1## wherein R is hydrogen, C.sub.1 -C.sub.4 alkyl or a carboxy substituted alkyl group; R.sub.1 is H or C.sub.1 -C.sub.4 alkyl; n is 0, 1 or 2; and A and A' independently are hydrogen, C.sub.1 -C.sub.4 alkyl or allyl; and pharmaceutically acceptable salts thereof are broad spectrum antibiotics useful in the treatment of gram positive and gram negative infections of mammals.