37409-69-1

Upstream product

• 22123-17-7 4-isopropylidene-5-methyl-2-phenyl-2,4-dihydro-pyrazol-3-one 
• 89-25-8 edaravone 
• 35104-74-6 5-methyl-4-naphthalen-2-ylmethylene-2-phenyl-2,4-dihydro-pyrazol-3-one 
• 36755-40-5 2,2,7-trimethyl-5-phenyl-1-oxa-5,6-diazaspiro<2.4>hept-6-en-4-one 

Relevant academic research and scientific papers

A New Synthesis of 4,5-Dihydroxy-pyrazoles

1-Aryl-pyrazolin-5-ones 1 are converted by Knoevenagel condensation with acetone or by reaction with 2,2-dimethyl-1,3-dioxolane 6 to 1-aryl-4-isopropyliden-pyrazolin-5-ones 2.The compounds 2 are epoxidized by hydrogen peroxide forming the spiro-epoxides 3, which can be cleaved to 4,5-dihydroxy-pyrazoles 4 under acidic conditions. 4-Acetoxy-5-hydroxy-pyrazoles 13 are formed directly, when 3 are cleaved in presence of acetic anhydride.The 3,3',3'-trimethyl-1-(4-nitro-phenyl)-pyrazolin-4-spiro-2'-oxiran-5-one 3b undergoes rearrangement to the 1,3-dioxolopyrazole 12.

Pyrazolinone Carbonyl Ylides: Novel Photochemistry of Oxiran and Diazo-compounds

A series of oxopyrazoline-4-spiro-oxirans and 4-diazo-3-methyl-1-phenyl-5-oxo-2-pyrazoline have been photolysed to generate reactive intermediates incorporating the pyrazolinone ring, which have been trapped with nucleophilic solvents and investigated by