Synthesis of 5‐cyanopyrazolo[3,4‐ b ]pyridines in the reaction of 5‐amino‐3‐methyl‐1‐phenylpyrazole with arylidene derivatives of malonodinitrile and ethyl cyanoacetate

This paper describes the synthesis of a new series of 6‐amino‐4‐aryl‐5‐cyanopyrazolo[3,4‐ b ]pyridines 4 and 4‐aryl‐5‐cyano‐6 H ‐pyrazolo[3,4‐ b ]pyridin‐6‐ones 5 from the reaction of 5‐amino‐3‐methyl‐1‐phenylpyrazole 1 with arylidene derivatives of malonodinitrile 2 and ethyl cyanoacetate 3 . The structure of the final compounds was determined on the basis of nmr measurements, especially by 1 H, 1 H‐, 1 H, 13 C‐COSY, DEPT and X‐ray diffraction.