title: Optimization of the selective monohydrolysis of diethyl 4-aryl-4H-pyran-3,5-dicarboxylates.
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.
authors.affiliation: College of Life Science and Bio-engineering, Beijing University of Technology, Pingleyuan Street Number 100, Chaoyang District, Beijing 100124, China.
authors.forename: Jiaojiao
authors.initials: J
authors.lastname: Duan
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Song
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
authors.forename: Xiuqing
authors.initials: X
authors.lastname: Song
mesh_terms: D004952:Esters / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D019789:Tetraethylammonium / Q000737:chemistry
chemical_list: D004952:Esters; D000644:Quaternary Ammonium Compounds; D019789:Tetraethylammonium