82619-26-9Relevant academic research and scientific papers
Knoevenagel condensation of aromatic aldehydes with ethyl 4-Chloro-3-oxobutanoate in ionic liquids
De Paula, Bruno R.S.,Zampieri, Da?vila S.,Zukerman-Schpector, Julio,Tiekink, Edward R.T.,Rodrigues, Jose? Augusto R.,Moran, Paulo J.S.
experimental part, p. 825 - 830 (2012/06/18)
Knoevenagel condensations of aromatic aldehydes with ethyl 4-chloro-3-oxobutanoate catalyzed by morpholine/acetic acid were carried out in ionic liquids to give ethyl 2-chloroacetyl-3-arylpropenoates in 44-84percent yield after 0.5 to 2 h at room temperature (25-28 °C). These conditions represent a greener protocol for the Knoevenagel condensation than those using refluxing benzene or toluene as solvent. Aromatic aldehydes having aryl groups 4-chlorophenyl, 4-methoxyphenyl, 2-thiofuranyl, 2-furanyl, phenyl and 3,4-methylenedioxyphenyl gave (E)/(Z) diastereomeric ratios of products from 56/44 to 85/15. The two isomers of each compound were separately isolated and characterized. The structure of the (E)-isomer of ethyl 2-chloroacetyl-3-(3',4' methylenedioxyphenyl)propenoate was determined by X-ray crystallography and an unequivocal methodology of (E)/(Z)-structural analysis by 13C NMR (nuclear magnetic resonance) is presented.
