Studies on the synthesis of heterocyclic compounds. Part I. The pschorr reaction in the pyrazole series

Abstract

Abstract Preparation and structural evidence of N ‐methyl‐(1,3‐R,R'‐pyrazol‐5‐yl)‐ o ‐nitrobenzamides (VIIIa, b) are discussed. Diazotisation of related o ‐aminobenzamides XIa,b followed by the Pschorr reaction afforded a very complex mixture from which pyrazolo[3,4‐ c ]isoquinolin‐5‐ones XIIa.b in 7–10% yields together with N ‐methyl‐(1,3‐R,R'‐pyrazol‐5‐yl)‐ o ‐hydroxybenzamides (XIIIa) in 15–20% yields were isolated.