Optimization of the selective monohydrolysis of diethyl 4-aryl-4H-pyran-3,5-dicarboxylates
Jiaojiao Duan1, Xiaohui Song, Hong Yan
1College of Life Science and Bio-engineering, Beijing University of Technology, Pingleyuan Street Number 100, Chaoyang District, Beijing 100124, China.
Abstract:
A simple, efficient and eco-friendly procedure for the selective monohydrolysis of diethyl 2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylates under quaternary ammonium salt catalysis conditions is presented. The catalytic activities of various quaternary ammonium salts were investigated using different molar ratios of NaOH and water-organic solvent mixtures. The results indicate that the combination of 1.0 equivalent of tetraethyl-ammonium bromide (TEAB) with 1.2 equivalents of NaOH in a 10% water-ethanol media at 40 °C displays remarkable selectivity for the monohydrolysis of diethyl 2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylates. The utility of this process is demonstrated by the monohydrolysis of a series of 4-aryl-4H-pyran-3,5-dicarboxylate esters to afford the corresponding monoesters in 20-80% yields under the optimized conditions.
More Related Videos
10:12Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols
Published on: April 4, 2014
09:54Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes
Published on: September 12, 2018
Related Concept Videos
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
Preparation of Diols and Pinacol Rearrangement
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
