An improved method for aldol condensation catalyses by Amberlyst A-26 OH: application in the synthesis of pseudoionone derivative, 11,15-dimethylhexadeca-8,10,14-trien-7-one

摘要

This paper reports the improved procedure for aldol condensation between citral and 2-octanone with Amberlyst A-26 OH to give 11,15-dimethyl-hexadeca-8,10,14-trien-7-one. The improved synthesis utilizing Amberlyst A-26 OH as the solid catalyst produces better yield (93.0%) and enables simple work-up procedure. The experimental conditions are evaluated and optimized at 2-octanone/citral molar ratio of 10, catalyst amount of 5% (mole of citral), and temperature of 60 degrees C in 3.5 h reaction time. 11,15-Dimethyl-hexadeca-8,10,14-trien-7-one is isolated using preparative thin layer chromatography with hexane: ethyl acetate (9.5:0.5) and confirmed by gas chromatography-mass spectrometry (GC-MS), ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR).