Electron impact induced fragmentation mechanisms of trans α aryl β enamino esters were investigated using mass analyzed ion kinetic energy (MIKE) spectrometry and high resolution accurate mass data...Electron impact induced fragmentation mechanisms of trans α aryl β enamino esters were investigated using mass analyzed ion kinetic energy (MIKE) spectrometry and high resolution accurate mass data. It was found that the main characteristic fragmentations of compounds studied were: an odd electron ion M +· -EtOH was formed by losing a neutral molecule of ethanol; and the skeletal rearrangements took place; and the ring opening reaction happened after losing a carbon monoxide; and the typical McLafferty rearrangement underwent in ester group. The cyclization reaction caused by losing neutral molecule of TsNH 2 due to the ortho effects of substituted group of aromatic ring was also observed.展开更多
Fluoroboric acid adsorbed on silica-gel（HBF4·SiO2） has been found to be an extremely efficient and recyclable catalyst for the preparation of β-enaminones and β-enamino esters under solvent-free conditions.
An efficient synthetic protocol for the 1,4-diaryl-1,4-dihydropyridines was developed via the domino four-component reaction of arylamine,acetylenedicarboxylate,aromatic aldehyde and ethyl acetoacetate.The reaction me...An efficient synthetic protocol for the 1,4-diaryl-1,4-dihydropyridines was developed via the domino four-component reaction of arylamine,acetylenedicarboxylate,aromatic aldehyde and ethyl acetoacetate.The reaction mechanism involves the formation of β-enamino ester and its sequential Michael addition to arylidene acetoacetate.展开更多
文摘Electron impact induced fragmentation mechanisms of trans α aryl β enamino esters were investigated using mass analyzed ion kinetic energy (MIKE) spectrometry and high resolution accurate mass data. It was found that the main characteristic fragmentations of compounds studied were: an odd electron ion M +· -EtOH was formed by losing a neutral molecule of ethanol; and the skeletal rearrangements took place; and the ring opening reaction happened after losing a carbon monoxide; and the typical McLafferty rearrangement underwent in ester group. The cyclization reaction caused by losing neutral molecule of TsNH 2 due to the ortho effects of substituted group of aromatic ring was also observed.
文摘Fluoroboric acid adsorbed on silica-gel（HBF4·SiO2） has been found to be an extremely efficient and recyclable catalyst for the preparation of β-enaminones and β-enamino esters under solvent-free conditions.
基金Supported by the National Natural Science Foundation of China(No.20972132)the Fund of Key Laboratory of Environmental Resource and Material,Jiangsu Province,China
文摘An efficient synthetic protocol for the 1,4-diaryl-1,4-dihydropyridines was developed via the domino four-component reaction of arylamine,acetylenedicarboxylate,aromatic aldehyde and ethyl acetoacetate.The reaction mechanism involves the formation of β-enamino ester and its sequential Michael addition to arylidene acetoacetate.
