CAS 114138-50-0: 5-Hydroxy-1-phenyl-1H-pyrazole-3-carboxylic acid

5-Hydroxy-1-phenyl-1H-pyrazole-3-carboxylic acid is a heterocyclic compound. It has been shown to react with sodium hydroxide to give a red solution, which is indicative of the presence of an acidic proton. This reaction can be seen by titration experiments and by examining the red shift in its UV spectrum. The 5-hydroxy group on this molecule is a tautomeric form that changes to the pyrazolone form when heated or when in contact with strong bases such as hydrazine. Substituents on this molecule may have effects on the shift of its UV spectrum, depending on their acceptor or substituent effects.