Thermal-regulated PEG1000-based ionic liquid/PM for one-pot three-component synthesis of 2,4,5-trisubstituted imidazoles

Abstract

A novel recyclable temperature-dependant phase-separation catalytic system comprised of PEG₁₀₀₀-based functional dicationic acidic ionic liquid and propylene glycol monomethyl ether was developed. This catalytic system could be used for the synthesis of 2,4,5-trisubstituted imidazoles via one-pot three-component condensation with various aldehydes, benzil and ammonium acetate in reasonable to good yield of 81–95%. The reaction was accomplished homogeneously at 70 °C, while the products was separated from the catalyst system by liquid/liquid phasic-separation at room-temperature, and the catalyst could be reused at least eight times without significantly decreasing the catalytic activity.