1623809-09-5

Upstream product

• 104-88-1 4-chlorobenzaldehyde 
• 14506-33-3 1-(4-chlorophenyl)but-3-en-1-ol 
• 6294-89-9 hydrazinecarboxylic acid methyl ester 
• 95827-00-2 1-(4-chlorophenyl)but-3-en-1-one 

Downstream Products

• 1623809-22-2 C₁₂H₁₂BrClN₂O₂ 
• 135641-71-3 methyl 3-(4-chlorophenyl)-1H-pyrazole-1-carboxylate 

Relevant academic research and scientific papers

Copper-Catalyzed Aerobic Cyclization of β,γ-Unsaturated Hydrazones with Concomitant CC Bond Cleavage

A Cu-catalyzed aerobic oxidative cyclization of β,γ-unsaturated hydrazones for the preparation of pyrazole derivatives has been developed. The hydrazonyl radical promoted the cyclization, along with a concomitant CC bond cleavage of β,γ-unsaturated hydrazones. This process has been verified via several control experiments, including a radical-trapping study, an 18O-labeling method, and the identification of the possible byproducts. The advantages of this reaction include operational simplicity, a broad reaction scope, and a mild selective reaction process.

Efficient synthesis of dihydropyrazoles by halocyclization of β,γ-unsaturated hydrazones

An efficient halocyclization of β,γ-unsaturated hydrazones with N-bromosuccinimide was developed without the addition of any additives under mild reaction conditions to provide facile access to biologically important 4,5-dihydropyrazoles. Under the optimized conditions, a variety of highly substituted 4,5-dihydropyrazole derivatives were obtained in generally good yields. Moreover, this reaction can be further applied to the synthesis of pyrazoles in a one-pot fashion. Copyright