Evidence for Radical-Mediated Catalysis by HppE: A Study Using Cyclopropyl and Methylenecyclopropyl Substrate Analogues
摘要:
(S)-2-Hydroxypropylphosphonic acid epoxidase (HppE) is an unusual mononuclear iron enzyme that catalyzes the oxidative epoxidation of (S)-2-hydroxypropylphosphonic acid ((S)-HPP) in the biosynthesis of the antibiotic fosfomycin. HppE also recognizes (R)-2-hydroxypropylphosphonic acid ((R)-HPP) as a substrate and converts it to 2-oxo-propylphosphonic acid. To probe the mechanisms of these HppE-catalyzed oxidations, cyclopropyl- and methylenecyclopropyl-containing compounds were synthesized and studied as radical clock substrate analogues. Enzymatic assays indicated that the (S)- and (R)-isomers of the cyclopropyl-containing analogues were efficiently converted to epoxide and ketone products by HppE, respectively. In contrast, the ultrafast methylenecyclopropyl-containing probe inactivated HppE, consistent with a rapid radical-triggered ring-opening process that leads to enzyme inactivation. Taken together, these findings provide, for the first time, experimental evidence for the involvement of a C2-centered radical intermediate with a lifetime on the order of nanoseconds in the HppE-catalyzed oxidation of (R)-HPP.
[EN] ADAMTS INHIBITORS, PREPARATION METHODS AND MEDICINAL USES THEREOF<br/>[FR] INHIBITEURS D'ADAMTS, LEURS PROCÉDÉS DE PRÉPARATION ET LEURS UTILISATIONS MÉDICALES
申请人:ETERNITY BIOSCIENCE INC
公开号:WO2021158626A1
公开(公告)日:2021-08-12
Compounds of formula (I) useful as inhibitors of ADAMTS-5 and/or ADAMTS-4, pharmaceutical compositions thereof, and use of them as therapeutic agents for the treatment of diseases involving degradation of cartilage or disruption of cartilage homeostasis, in particular osteoarthrosis and/or rheumatoid arthritis, are disclosed.
A new, practical, synthesis of β-ketophosphonates relying on the conversion of the organolithium reagentfrom a dialkyl methylphosphonate into the correspondingorganocopperreagent, and its reaction with acylchlorides is described. The structure of the intermediate organocopperreagents is discussed.
A one-pot strategy to synthesize β-ketophosphonates: silver/copper catalyzed direct oxyphosphorylation of alkynes with H-phosphonates and oxygen in the air
A highly efficient one-pot strategy has been developed for the synthesis of beta-ketophosphonates directly from alkynes and dialkyl H-phosphonates in the presence of widely available AgNO3/CuSO4 and K2S2O8 at room temperature under open-air conditions.
Gold(I)-Catalyzed Hydration of Alkynylphosphonates: Efficient Access to β-Ketophosphonates
作者:Longyong Xie、Rui Yuan、Ruijia Wang、Zhihong Peng、Jiannan Xiang、Weimin He
DOI:10.1002/ejoc.201400066
日期:2014.5
A general, efficient, and highly regioselective protocol with the use of a gold(I) complex catalytic system for the transformation of alkynylphosphonates into the corresponding β-ketophosphonates has been successfully developed. This method produces a variety of β-ketophosphonates with the advantages of mild reaction conditions, high functional-group tolerance, and excellent yields.