S-Acylation of aliphatic and aromatic thiols with carboxylic acids and their esters over solid acid catalysts in the gas phase at temperatures above 200°C
Benzenethiol is reacted with acetic acid in a hydrogen stream over [(Mo6Cl8)Cl4(H2O)2]·6H2O. Catalytic activity of the clusters appears above 200 °C, yielding S-phenyl thioacetate. The selectivity is 98% at 300 °C. Niobium, tantalum, and tungsten halideclusters with the same octahedral metal framework also catalyze the reaction. Benzoic acid and aliphatic carboxylic acids afford the corresponding S-phenyl
class of electron-deficient reagents for Mitsunobuesterificationreactions. Among these compounds, 4,4′-azopyridine was found to be the most suitable one for esterification and thioesterification reactions. This new reagent promises to provide general and complementary solutions for separation problems in Mitsunobureactions without restricting the reaction scope and facilitates the isolation of its
The disclosure provides methods and compositions for delivering polynucleotides into cells. The disclosure provides transiently protected polynucleotides comprising an anionic charge-neutralizing moiety/group, which may also confer additional functionality. These compounds can enter the cytosol of cells by endocytic or macropinocytic mechanisms. The transient protecting group is bioreversible, i.e., once inside a cell, it is designed to be removed by enzymatic activity or by passive intracellular methods (e.g., changes in pH or reductive environment).
[EN] POLYNUCLEOTIDES HAVING BIOREVERSIBLE GROUPS<br/>[FR] POLYNUCLÉOTIDES POSSÉDANT DES GROUPES BIORÉVERSIBLES
申请人:UNIV CALIFORNIA
公开号:WO2014031575A1
公开(公告)日:2014-02-27
The disclosure provides methods and compositions for delivering polynucleotides into cells. The disclosure provides transiently protected polynucleotides comprising an anionic charge- neutralizing moiety/group, which may also confer additional functionality. These compounds can enter the cytosol of cells by endocytic or macropinocytic mechanisms. The transient protecting group is bioreversible, i.e., once inside a cell, it is designed to be removed by enzymatic activity or by passive intracellular methods (e.g., changes in pH or reductive environment).
A simple and convenient method for preparation of carboxylic acid alkyl esters, phenolic and thioesters using chlorodiphenylphosphine/I2 and imidazole reagent system
作者:Najmeh Nowrouzi、Abdol Mohammad Mehranpour、Javad Ameri Rad
DOI:10.1016/j.tet.2010.10.022
日期:2010.12
Condensation of carboxylicacids with alcohols, phenols and thiols proceeded smoothly to afford carboxylicacid alkyl esters, phenolic esters and thioesters by using the combination of chlorodiphenylphosphine, imidazole and molecular iodine in refluxing acetonitrile. Esterification with this mixed reagent system gave the corresponding products in excellent yields. The phosphorus-containing byproduct