l-(+)-Tartaric acid and choline chloride based deep eutectic solvent: An efficient and reusable medium for synthesis of N-substituted pyrroles via Clauson-Kaas reaction
作者:Ping Wang、Fei-Ping Ma、Zhan-Hui Zhang
DOI:10.1016/j.molliq.2014.07.015
日期:2014.10
l-(+)-Tartaric acid–choline chloride based deep eutectic solvent has been found to be an effective promoted medium for Clauson-Kaas reaction of aromatic amines and 2,5-dimethoxytetrahydrofuran. Structurally diverse N-substituted pyrroles were obtained in high to excellent yields under mild conditions. The deep eutectic solvent is inexpensive, non-toxic, reusable and biodegradable.
Unique chemoselective Clauson–Kass reaction of substituted aniline catalyzed by MgI2 etherate
作者:Xingxian Zhang、Junchen Shi
DOI:10.1016/j.tet.2010.12.018
日期:2011.2
Clauson–Kass reaction of various substitutedaniline, primary aryl amide, and sufonyl amide with 2,5-dimethoxytetrahydrofuran was realized in the presence of 10 mol % of MgI2 etherate in a mild, efficient, and highly chemoselective manner. Iodide counterion and solvents (i.e., MeCN) played the critical roles for the unique reactivity of this catalytic system.
AN EFFICIENT AND RAPID SYNTHESIS OF N-SUBSTITUTED PYRROLES BY MICROWAVE ASSISTED SOLID ACID CATALYSIS
作者:Mohammed Abid、Shainaz M. Landge、Béla Török
DOI:10.1080/00304940609356444
日期:2006.10
total synthesis of these compounds .' Accordingly, extended efforts have been made toward the synthesis of wide range of pyrrole derivatives. Most of these methods involve various cyclocondensations reactions resulting in 254or polysubstituted pyrroles.2 However, the environmentally benign synthesis of N-monosubstituted pyrroles is still a challenge. The commonly used traditional P205 catalysis has disadvantages
The construction of the pyrrolidine ring about a nitrogen of a primary amine by a reductive condensation reaction using 2,5-dimethoxytetrahydrofuran and sodium borohydride in acidic water medium is described. The reaction is fast, affords good to excellent yields and appears insensitive to electron effects and severe steric hindrance; it is found to be compatible with a large variety of aryl substituents, including nitro and oxo groups. The reaction allows the introduction of two deuterium atoms, with label conservation, in both the α-positions of the pyrrolidine ring by the use of sodium borodeuteride instead of sodium borohydride.
A new magnetic nanoparticle-supported catalyst for Clauson-Kaas reaction. The corresponding N-substituted pyrroles in by magnetic separation and recycled for antimony catalyst was prepared and evaluated as a recoverable reaction proceeds efficiently in aqueous medium to give the high yield. The immobilized catalyst could be easily recovered six times without significant loss of its catalytic activity. (c) 2013 Elsevier B.V. All rights reserved.