Issue 0, 1982

Reactions with heterocyclic diazonium salts: novel synthesis of pyrazolo[4,3-c]pyridazines and of pyrazolo[4,3-c]pyrazoles

Abstract

Diazotised 4-amino-1,5-dimethyl-2-phenylpyrazol-3(2H)-one (1) coupled with active methylene nitriles to yield the corresponding cyanohydrazones (3a–c) and (11). Compounds (3a–c) afforded the 4-(3-aminopyrazol-4-ylidenehydrazino)-1,5-dimethyl-2-phenylpyrazol-3(2H)-ones (5a–c) on treatment with hydrazine hydrate, and cyclised to give the pyrazolo[4,3-c]pyridazines (7a–c) on treatment with ethanolic hydrochloric acid. The hydrazone (11) cyclised to give the pyridazin-6-one derivative (12) when boiled under reflux in ethanol. Diazotised pyrazolone (1) coupled with 3-chloropentane-2,4-dione and with ethyl 2-chloro-3-oxobutanoate to yield the pyrazolo[4,3-c]pyrazole derivatives (9a and b).

Article information

Article type
Paper

J. Chem. Soc., Perkin Trans. 1, 1982, 989-991

Reactions with heterocyclic diazonium salts: novel synthesis of pyrazolo[4,3-c]pyridazines and of pyrazolo[4,3-c]pyrazoles

M. H. Elnagdi, H. A. Elfahham, M. R. H. Elmoghayar, K. U. Sadek and G. E. H. Elgemeie, J. Chem. Soc., Perkin Trans. 1, 1982, 989 DOI: 10.1039/P19820000989

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