A facile and efficient one-pot synthesis of 1,4-dihydropyridines from aldehyde, 1,3-dicarbonyl compounds and ammonium acetate in the presence of Ce(SO4)2-SiO2 at 80°C under solvent-free conditions is described. Compared with the classical Hantzsch reaction, this novel method consistently has the advantages of excellent yields and short reaction time.
4-Aminopyridine resin-immobilized palladium catalyst was prepared by a simple procedure, which exhibited excellent activity at low loading levels for the phosphine-free Heck vinylation of activated and non-activated aryl or heteroaryl substrates with olefins in air. This method has the advantage of environmental benignity, generality, simplicity and potential for recycling of the resin catalyst.
