Studies in the field of nitrogen heterocyclic compounds. Part XVI. A novel Dimroth type rearrangement of some 1-amino-2-pyridone derivatives was written by Balicki, Roman. And the article was included in Polish Journal of Chemistry in 1984.Safety of 3-(Trifluoromethyl)-1H-pyrazol-5(4H)-one This article mentions the following:
Cyclocondensation of RCOCH2CO2Et [R = Me, pyridyl, (substituted) Ph, CF3, CO2Et] with H2NNHCOCH2CN in EtOH/KOH gave the aminopyridone salts I (R1 = K) (II). On treatment with acid, II (R = CF3, CO2Et), possessing strong electron-withdrawing groups at C-4, underwent the title rearrangement to give pyrazolopyridines III, whereas the other II gave the expected aminopyridones I (R1 = H). The mechanism of the rearrangement is discussed. In the experiment, the researchers used many compounds, for example, 3-(Trifluoromethyl)-1H-pyrazol-5(4H)-one (cas: 401-73-0Safety of 3-(Trifluoromethyl)-1H-pyrazol-5(4H)-one).
3-(Trifluoromethyl)-1H-pyrazol-5(4H)-one (cas: 401-73-0) belongs to pyrazole derivatives. The strategies for the synthesis of pyrazoles generally can be applied for the construction of indazoles. Protonation of pyrazole in strong acid leads to pyrazolium cations, which undergo electrophilic substitution preferentially at C3 rather than C4. The pyrazole anion is not reactive toward nucleophiles but is mostly reactive to electrophiles.Safety of 3-(Trifluoromethyl)-1H-pyrazol-5(4H)-one
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics