For example, when 1 reacted with ethyl acetoacetate derivatives 39 or diethyl malonate 64 in ethyl alcohol in presence of potassium hydroxide, the reaction gave N -aminopyridone derivatives 65 and 66, respectively (Scheme 25). N -aminopyridones were also prepared via the reaction of cyanoacetohydrazide 1 with arylidene derivatives. This route has been utilized frequently in recent literature for the synthesis of such ring systems . Thus, it has been shown that cyanoacetohydrazide 1 reacted with the arylidene malononitrile derivatives 67 in ethyl alcohol and piperidine at room temperature to give the corresponding N-aminopyridones 68, these products were assumed to be formed via the Michael adduct intermediates which then undergo self-cyclization (Scheme 26).