Reactions with heterocyclic diazonium salts: novel synthesis of pyrazolo[4,3-c]pyridazines and of pyrazolo[4,3-c]pyrazoles
- 1 January 1982
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- No. 4,p. 989-991
- https://doi.org/10.1039/p19820000989
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).This publication has 0 references indexed in Scilit: