The 3-Pyrazolone, with the CAS registry number 137-45-1, is also known as 3-Hydroxypyrazole. This chemical's molecular formula is C₃H₄N₂O and molecular weight is 84.07666. Its IUPAC name is called 1,2-dihydropyrazol-3-one.

Physical properties of 3-Pyrazolone: (1)ACD/LogP: -0.39; (2)ACD/BCF (pH 5.5): 1; (3)ACD/BCF (pH 7.4): 1; (4)ACD/KOC (pH 5.5): 13.52; (5)ACD/KOC (pH 7.4): 11.94; (6)#H bond acceptors: 3; (7)#H bond donors: 2; (8)Index of Refraction: 1.486; (9)Molar Refractivity: 20.26 cm³; (10)Molar Volume: 70.5 cm³; (11)Surface Tension: 33.4 dyne/cm; (12)Density: 1.191 g/cm³; (13)Flash Point: 151 °C; (14)Enthalpy of Vaporization: 59.09 kJ/mol; (15)Boiling Point: 326.1 °C at 760 mmHg; (16)Vapour Pressure: 0.000116 mmHg at 25°C.

Preparation: this chemical can be prepared by trimethylsilylpropiolyl chloride. This reaction will need reagent hydrazine hydrate and solvent methanol. The reaction time is 1 hour with reaction temperature of -50 °C. The yield is about 95%.

You can still convert the following datas into molecular structure:
(1)Canonical SMILES: C1=CNNC1=O
(2)InChI: InChI=1S/C3H4N2O/c6-3-1-2-4-5-3/h1-2H,(H2,4,5,6)
(3)InChIKey: XBYRMPXUBGMOJC-UHFFFAOYSA-N