It has been reported that, the reaction of 2'-acetyl-2-cyanoacetohydrazide 35 with aromatic aldehydes in ethanol and triethylamine as a catalyst gave the corresponding c-arylidine derivatives. However. When the reaction of 35 with arylaldehyde was carried out in acetic acid instead of ethanol triethylamine. The pyrazolopyridines 51 were obtained. The reaction course is assumed to proceed via an ylidine bis intermediate as illustrated in the following Scheme 19 6 . The reaction between commercially available cyanoacetohydrazide 1 and 4methoxy-phenylsulfonyl chloride in ethanol resulted in the formation of the sulfonamide 56, which precipitated from solution. Cyclization of sulfonamide 56 to pyrazolone 57 took place in an ethanolic solution of KOH, followed by neutralization with AcOH (Scheme 21) . Recently, N-amino-2-pyridones have proved to be useful synthetic intermediates. Few synthetic procedures are reported for their Preparations, among which we may mention the reaction of hydrazine with 2-pyrones, which are in turn prepared in low yields from the open chain compounds 26-28 . However, the condensation reaction of cyanoacetohydrazide via its methylene and amido groups with β-diketo compounds represent a facile and a general approach for the preparation of such compounds through one step reaction.