Facile Synthesis of New 6‐Alkylamino‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile Derivatives

Abstract

Some new derivatives of 6‐alkylamino‐1,3‐diphenyl‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitrile have been prepared through a Knoevenagel condensation reaction of 5‐chloro‐1,3‐diphenyl‐1H‐pyrazole‐4‐carbaldehyde with malononitrile in ethanol containing a few drops of glacial acetic acid at reflux temperature followed by cyclization with primary alkyl amines in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as catalyst in refluxing ethanol. The products were characterized on the basis of IR, 1H NMR, and 13C NMR spectral and microanalytical data. The 1H NMR data ruled out the formation of the alternative cyclized isomers 6‐imino‐7‐alkyl‐1,3‐diphenyl‐6,7‐dihydro‐1H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitriles.