Proton NMR studies of protonation in pyridazin-3(2H)-one and 6-hydroxypyridazin-3(2H)-one was written by Barlin, Gordon B.;Fenn, M. David. And the article was included in Australian Journal of Chemistry in 1979.Quality Control of 4-Hydroxypyridazine This article mentions the following:
A 1H NMR study of protonation in pyridazin-3-ol and pyridazine-3,6-diol revealed that the processes are not simple and suggests that a mobile tautomeric equilibrium may be involved. In the experiment, the researchers used many compounds, for example, 4-Hydroxypyridazine (cas: 20733-10-2Quality Control of 4-Hydroxypyridazine).
4-Hydroxypyridazine (cas: 20733-10-2) belongs to pyridazine derivatives. The pyridazine derivatives are mostly present in biologically active compounds and are also present with different pharmacophores. Pyridazine can act as a hydrogen bond acceptor to improve the physicochemical properties of drug molecules by increasing their water solubility, and has a high affinity for complexing with targets due to its dipole moment.Quality Control of 4-Hydroxypyridazine
Referemce:
Pyridazine – Wikipedia,
Pyridazine | C4H4N2 – PubChem