Various 1H,6H‐pyrano[2,3‐c]pyrazol‐6‐ones (III‐XXIII) were obtained from β‐keto esters and 1H‐pyrazol‐5‐ones or hydrazines. Nitrations, chlorinations and brominations of these pyranopyrazoles were also carried out giving the corresponding derivatives (XXIV‐LXIV). The pyrone ring is the more reactive one in these reactions and the preferred position of attack is the 5‐position. The substitution products are formed by the addition‐elimination route.

Hydrazine (I) und Acylessigsäureester (II) kondensierten zu den Pyrazo‐ Ionen (III), die mit weiteren, ggfs.