Electrocatalytic tandem Knoevenagel–Michael reaction of 3-methyl-2-pyrazolin-5-ones, aryl aldehydes and cyano-functionalized C–H acids: Facile and convenient multicomponent way to substituted 3-(5-hydroxy-3-methylpyrazol-4-yl)-3-arylpropionitriles

Electrochemically induced catalytic tandem Knoevenagel–Michael reaction of 3-methyl-2-pyrazolin-5-ones, aryl aldehydes and malononitrile or alkyl cyanoacetates in alcohols in an undivided cell in the presence of sodium bromide as an electrolyte results in the formation of substituted 3-(5-hydroxy-3-methylpyrazol-4-yl)-3-arylpropionitriles in 75–97% yields. The developed efficient electrocatalytic approach to the corresponding 3-(5-hydroxy-3-methylpyrazol-4-yl)-3-arylpropionitriles is beneficial from the viewpoint of diversity-oriented large-scale processes and represents novel, facile and environmentally benign synthetic concept for multicomponent reactions strategy.