Kinetic and structural consequences of the leaving group in substrates of a class C β-lactamase
摘要:
The class C beta-lactamase of Enterobacter cloacae P99 is known to catalyze the hydrolysis of certain acyclic (thio)esters. Previous experiments have employed thioglycolate, in-hydroxybenzoate, and phenylphosphate leaving groups. The relative effectiveness of these leaving groups has now been quantitatively assessed by employment of a series of compounds with common acyl groups, and found to rank in the order phenylphosphate > m-hydroxybenzoate > thioglycolate. Structural models suggest that these leaving groups interact during acylation principally with Tyr 150, Lys 315, and Thr 316 of the beta-lactamase active site. The positions of the leaving group carboxylates in these models is compared with those in published crystal structures of complexes of class C beta-lactamases with beta-lactams. The particular effectiveness of the acyl phosphate indicates the positions of two oxyanions that strongly interact with the active site. This information should be useful in the design of inhibitors of class C beta-lactamases. (C) 2004 Elsevier Ltd. All rights reserved.
Discovery of Benzamide Analogues as a Novel Class of 5-HT3 Receptor Agonists
作者:Charlotte G. Jørgensen、Bente Frølund、Jan Kehler、Anders A. Jensen
DOI:10.1002/cmdc.201000444
日期:2011.4.4
the initial hit. The benzamide scaffold constitutes a noveltype of 5‐HT3 receptor agonist, as it does not possess a positively charged functionality, which is essential for the binding of all orthosteric ligands to the receptor. Preliminary investigations suggest that the compounds may exert their effects on 5‐HT3 receptors by binding to an allosteric site in the receptor complex.
Synthesis and preliminary biological evaluations of (+)-isocampholenic acid-derived amides
作者:Uroš Grošelj、Amalija Golobič、Damijan Knez、Martina Hrast、Stanislav Gobec、Sebastijan Ričko、Jurij Svete
DOI:10.1007/s11030-016-9668-9
日期:2016.8
The synthesis of two novel (+)-isocampholenic acid-derived amines has been realized starting from commercially available (1S)-(+)-10-camphorsulfonic acid. The novel amines as well as (+)-isocampholenic acid have been used as building blocks in the construction of a library of amides using various aliphatic, aromatic, and amino acid-derived coupling partners using BPC and CDI as activating agents. Amide
a state-of-the-art methodology enabling radical–radical coupling. The catalytic process involves forming an acyl azolium intermediate from the NHC catalyst and an acyl donor, followed by single electron reduction of this key intermediate, which is largely dependent on the photoredox catalyst. We designed a radical NHC catalysis in which the direct photoexcitation of a borate to form a high reducing
Combined Photoredox and Carbene Catalysis for the Synthesis of α-Amino Ketones from Carboxylic Acids
作者:Xiaochen Wang、Binbing Zhu、Yuxiu Liu、Qingmin Wang
DOI:10.1021/acscatal.1c05815
日期:2022.2.18
cross-coupling reactions between a wide range of carboxylic acids, a class of feedstock chemicals, and readily available N-alkyl anilines by means of single-electron N-heterocyclic carbene catalysis combined with photocatalysis provided access to structurally diverse α-amino ketones. The method features a broad substrate scope and is compatible with a wide array of functional groups. To demonstrate
Organic Photoredox-Catalyzed Silyl Radical Generation from Silylboronate
作者:Naho Takemura、Yuto Sumida、Hirohisa Ohmiya
DOI:10.1021/acscatal.2c01964
日期:2022.7.1
A visible-light-driven silyl radicalgeneration method from silylboronates has been developed. The activation of silylboronates with a catalytic amount of mild base promoted the single-electron oxidation process to form silyl radicals. Facile single electron transfer for the borate form readily occurred without hydrogen atom transfer for hydrosilane in the presence of various photoredox catalysts.