Poly(3,4‐dimethyl‐5‐vinylthiazolium) was synthesized from 3,4‐dimethyl‐5‐vinylthiazole through free radical polymerization and was examined as polymer precatalysts in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) for the thioesterification of aldehydes with thiols. The poly(5‐vinylthiazolium)/DBU had excellent catalytic activity and could be reused 10 times without a considerable loss of
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
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