The nitration of brominated pyrazoles in aqueous sulfuric acid was written by Chang, Kuei-Choo;Grimmett, M. Ross;Ward, David D.;Weavers, Rex T.. And the article was included in Australian Journal of Chemistry in 1979.Category: pyrazoles-derivatives This article mentions the following:
Nitration in 80% H2SO4 of 4-bromopyrazoles gives rise to considerable nitrodebromination. Compounds with no alkyl or aryl substituent on N give only the 4-nitro products, except 4-bromo-3-phenylpyrazole which gives the p-nitrophenyl compound N-Alkyl-4-bromopyrazoles give products of nitrodebromination as well as those arising from nitration in the 3- and/or 5-positions. N-Aryl-4-bromopyrazoles can also undergo nitration of the aryl substituent. In the experiment, the researchers used many compounds, for example, 3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4Category: pyrazoles-derivatives).
3-Methyl-4-nitro-1H-pyrazole (cas: 5334-39-4) belongs to pyrazole derivatives. The strategies for the synthesis of pyrazoles generally can be applied for the construction of indazoles. Pyrazoles can be selectively lithiated at different carbons and subsequently react with electrophiles depending on the substitution patterns.Category: pyrazoles-derivatives
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics