1- pyrazol-3-one, formation

One clear example of synthesis of pyrazoles by formation of the N,—Nj bond <84CHEC-I(5)167> is the ring closure of iminohydrazones (1-azadienes) to N f-pyrazoles (201) <86JHC459>. 

Oxidation of 5-Substituted Pyrazol-3(2H)-ones Formation of Alkynyl Esters. Oxidation of various 5-substituted pyrazol-3(2//)-ones proceeded with fragmentative loss of molecular nitrogen to yield methyl-2-alkynoates (eq 35). An analogous fragmentation process with pyrazol-3(2//)-ones occurs with Thallium(III) Nitrate Trihydrate and Lead(IV) Acetate. ... 

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