A facile protocol for the synthesis of 4-aryl-l,4,7,8-tetrahydro-3,5-dimethyldipyrazolo[3,4-b:4',3'-e]pyridine derivatives by a Hantzsch-type reaction

摘要

A facile and efficient protocol is described for the synthesis of 4-aryl-1,4,7,8-tetrahydro-3,5-dimethyl-dipyrazolo[3,4-b:4',3'-e']pyridine derivatives in good yields by the condensation of 3-methyl-1H-pyrazol-5(4H)-one, aromatic aldehydes, and ammonium acetate under catalyst-free conditions. The advantages of this protocol are operational simplicity, mild reaction conditions, high yields, and little environmental impact.