One-pot tandem reactions for direct conversion of thiols and disulfides to sulfonic esters, and Paal–Knorr synthesis of pyrrole derivatives catalyzed by TCCA
thiols is accomplished by oxidation with trichloroisocyanuric acid (TCCA), tetra-butylammonium chloride (t-Bu4NCl), and water. The sulfonyl chlorides are then further allowed to react with phenol derivatives in the same reaction vessel. Also, a facile synthesis of N-substituted pyrroles by the reaction of hexane-2,5-dione with primary amines has been accomplished using TCCA as a catalyst under mild condition
Silica sulfuric acid (SSA) as a solid acid heterogeneous catalyst for one-pot synthesis of substituted pyrroles under solvent-free conditions at room temperature
作者:Hojat Veisi
DOI:10.1016/j.tetlet.2010.02.052
日期:2010.4
A variety of N-substituted pyrroles have been synthesized by reacting γ-diketones with amines, diamines or triamine in the presence of silica sulfuricacid (SSA) at room temperature under solvent-free conditions. The experiment protocol features simple operations, and the products are isolated in high to excellent yields (70–98%).
A simple, economical, and green approach to the synthesis of N-substituted pyrrolesusingsodiumdodecylsulfate as surfactant in water is described. The experiment protocol features simple operations, and the products are isolated in high to excellent yields (60–98%).
Abstract Water was a suitable medium for Paal–Knorrpyrrole cyclocondensation. Hexa-2,5-dione was reacted with several aliphatic and aromatic primary amines, affording N-substituted 2,5-dimethyl pyrrole derivatives in good to excellent yields. An efficient, green method using water either as environmentally friendly solvent or catalyst was presented. GRAPHICAL ABSTRACT
Ascorbic acid as a multifunctional hydrogen bonding catalyst for Paal–Knorr synthesis of N-substituted mono- and bis-pyrroles: experimental and theoretical aspects
the catalytic mechanism of ascorbic acid in this reaction. The optimized calculations pointed out the presence of three possible bifunctional hydrogen bond donor sites and one hydrogen bond acceptor site in the molecular structure of ascorbic acid. Although all four possible complexes were studied, the two bidentate hydrogen bond complexes between ascorbic acid and the carbonyl group of hexane-2,5-dione