71989-66-7

Basic information

• Product Name: 4-bromo-3,5-dimethyl-1H-pyrazol-1-ol 2-oxide
• CAS NO: 71989-66-7
• Molecular Formula: C₅H₇BrN₂O₂
• Molecular Weight: 207.0253
• Mol File: 71989-66-7.mol
• Article Data: 2

Chemical Properties

• Boiling Point: 379.5°C at 760 mmHg
• Flash Point: 183.3°C
• Density: 1.85g/cm³
• Vapor Pressure: 2.67E-06mmHg at 25°C
• Refractive Index: 1.634
• CAS DataBase Reference: 4-bromo-3,5-dimethyl-1H-pyrazol-1-ol 2-oxide(CAS DataBase Reference)
• NIST Chemistry Reference: 4-bromo-3,5-dimethyl-1H-pyrazol-1-ol 2-oxide(71989-66-7)
• EPA Substance Registry System: 4-bromo-3,5-dimethyl-1H-pyrazol-1-ol 2-oxide(71989-66-7)

Safety Data

• Hazardous Substances Data: 71989-66-7(Hazardous Substances Data)

Upstream product

• 65304-44-1 (E)-3-bromo-3-penten-2-one 
• 157098-04-9 3-bromo-3-penten-2-one oxime 
• 71989-58-7 3,5-Dimethyl-2-oxy-pyrazol-1-ol 

Downstream Products

• 300-87-8 3,5-dimethyl-1,2-oxazole 
• 81945-73-5 1H-pyrazol-1-ol 
• 71989-59-8 3,5-Dimethyl-1-hydroxypyrazole 

Relevant articles and documents

Preparation of 4-Bromo-1-hydroxypyrazole 2-Oxides by Nitrosation of α-Bromo-α,β-unsaturated Ketoximes

Nitrosation of the oximes of 3-bromo-3-penten-2-one, 3-bromo-4-phenyl-3-buten-2-one, and 2-bromo-1,3-diphenyl-2-propen-1-one using sodium nitrite in acetic acid gave low yields of 4-pyrazolone 1,2-dioxides.Nitrosation using butyl nitrite in the presence of copper(II) sulfate and pyridine in aqueous ethanol produced insoluble copper complexes from which 3,5-dimethyl-, 3-methyl-5-phenyl-, and 3,5-diphenyl-4-bromo-1-hydroxypyrazole 2-oxides could be liberated by treatment with dilute potassium hydroxide, filtration, and acidification of the filtrate.High yields wereobtained with the first two oximes, but, presumably due to unfavorable stereochemistry of the oxime, the diphenyl derivative gave a lower yield of the complex, accompanied by 4-bromo- and 4-nitro-3,5-diphenylisoxazole and 4-oximino-3,5-diphenyl-4,5-dihydroisoxazole.