Ionic liquid catalyzed convenient synthesis of imidazo[1,2-a]quinoline under sonic condition

Abstract

Um protocolo eficiente para a síntese de derivados imidazol-[1,2-a]-quinolina a partir de aldeídos, enaminonas ou malononitrila e utilizando como catalisador acetato de 1,[Ac]) sob irradiação de ultrassom é descrito. Em comparação com outras metodologias, esta apresenta as vantagens de um tratamento reacional mais simples, condições reacionais mais suaves, rendimentos elevados e um procedimento ambientalmente aceitável.An efficient protocol for the synthesis of imidazo[1,2-a]quinoline from aldehydes, enaminones, and malononitrile using 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium acetate ([DBU][Ac]) as a catalyst under ultrasound irradiation is described. Compared with other methods, this new method has the advantages of easier work-up, milder reaction conditions, high yields and environmentally benign procedure.

DBU-Based Ionic Liquids

“…The reaction of DBU with acid under conventional conditions usually takes a long time to complete (e.g., 48 h). Raval's group successfully synthesized [DBUH][CH 3 CO 2 ] under ultrasound irradiation within 90 min [11]. In their experiment, aliquots of acetic acid (1 equiv.)…”

Highly water soluble room temperature superionic liquids of APIs

“…Bearing in mind the potential pharmaceutical application of these ionic liquids, we would like to stress that in general protic ILs are usually less toxic than the aprotic ones. [16][17][18][19][20][21] All prepared salts were obtained in high yield (89 to 100%) and purity levels using a sustainable synthetic methodology which guarantees an atom economy process. All novel API ionic liquids or salts were completely characterized by spectroscopic techniques, namely 1 H and 13 C NMR and FTIR, and elemental analysis.…”

Transition metal-free one-pot synthesis of nitrogen-containing heterocycles

“…Raval and co workers [188] synthesized a series of imidazole fused quinoline derivatives from equimolar amount of enaminones 304, aldehydes 305, and malononitrile 45 using 1,8-diazabicyclo [5.4.0]-undec-7-en-8-ium acetate (ionic liquid) and methanol (co-solvent). The reaction was carried out under ultrasound irradiation to afford all the products in good to high yield in less than 2 h (Scheme 88).…”