Chromogenic Carbamate and Acetal Substrates for Glycosaminidases
摘要:
The enzyme Dispersin B is a medicinally relevant beta-hexosaminidase with potential for use in the treatment of biofilm-related infections. Here we describe the synthesis and evaluation of a p-nitrophenyl glycosyl carbamate and a p-nitrophenyl glycosyl acetal as improved substrates of Dispersin B. The p-nitrophenyl glycosyl carbamate shows substantially improved analytical signal in continuous assays and superior kinetics (k(cat)/K-m 6.1 mM(-1) s(-1)) when compared to the benchmark substrate 4-nitrophenyl N-acetyl-beta-D-glucosaminide (k(cat)/K-m 0.021 mM(-1) s(-1)) in measuring Dispersin B activity. The improvements observed are compared to the activity of jack bean beta-hexosaminidase toward these substrates.
t-Butyl bromide-activated dimethyl sulphoxide reacts with phenols to give either methylthiomethylation or bromination products. Several equilibria are shown to be simultaneously present in the system; however, by appropriate choice of several parameters (basicity, temperature, and reactant ratio) it is possible to drive the reaction selectively in one direction. A general discussion on the mechanism
Synthesis of fluoromethyl ethers and fluoromethyl esters by the reaction of the corresponding methylthiomethyl ethers and methylthiomethyl esters with IF5-pyridine-HF
作者:Masataka Kunigami、Shoji Hara
DOI:10.1016/j.jfluchem.2014.05.008
日期:2014.11
Fluoromethyl ethers of various functionalized phenols were synthesized from the corresponding methylthiomethyl ethers by the reaction with IF5-pyridine-HF. A fluoromethyl ether of an aliphatic alcohol and a fluoromethyl ester of a carboxylic acid were also synthesized.