15808-13-6

Upstream product

• 5492-70-6 phenyl-glyoxal-2-(N-phenyl oxime ) 
• 100-63-0 phenylhydrazine 
• 25131-60-6 2-phenacylisoquinolinium bromide 
• 1074-12-0 phenylglyoxal hydrate 
• 59-88-1 phenylhydrazine hydrochloride 
• 16883-69-5 N-phenacylpyridinium bromide 
• 13735-81-4 1-styrenyloxytrimethylsilane 
• 62-53-3 aniline 

Downstream Products

• 26502-72-7 (4-hydroxy-1-phenyl-1H-pyrazol-3-yl)-phenyl-methanone 
• 95884-31-4 (4-Hydroxy-5-methyl-1-phenyl-1H-pyrazol-3-yl)-phenyl-methanone 
• 95884-33-6 3-benzoyl-4-hydroxy-1,5-diphenylpyrazole 

Relevant academic research and scientific papers

Iodine-Catalyzed Regioselective Oxidative Cyclization of Aldehyde Hydrazones with Electron-Deficient Olefins for the Synthesis of Mefenpyr-Diethyl

A regioselective synthesis of polysubstituted dihydropyrazoles and pyrazoles through an iodine-catalyzed oxidative cyclization strategy of aldehyde hydrazones with electron-deficient olefins is described. The protocol adopts very mild reaction conditions and provides desirable yields. The reaction is supposed to proceed via a cascade C-H functionalization, C-N bond formation, and oxidation sequential processes. The overall simplicity and regioselectivity of the catalytic system make this approach a valuable and step-economical tool to construct a C-C bond for the synthesis of Mefenpyr-Diethyl.

Quantification of the electrophilicities of diazonium ions

The kinetics of the reactions of arenediazonium ions with arenes, alkenes, allylsilanes, allylstannanes, and silyl ketene acetals have been studied in acetonitrile solution. The reactions follow second-order kinetics, and in several cases rate-determining attack of the diazonium ion has been proven by kinetic isotope effect studies (1a + 2b), by the independence of the allylsilane reactivities of the rate of desilylation (1a + 10a, d) and by the independence of the rate constants of the diazonium counterion. A decrease of the rate constant with increasing solvent donor ability (correlation with Gutmann's donor number) was found. The reactions of diazonium ions with π-nucleophiles roughly follow the correlation lgk (20°C) = s (E + N), previously derived for the reactions of carbocations with nucleophiles. With the E parameters derived for diazonium ions, rate constants for azo couplings with aromatic and nonaromatic π-nucleophiles can be predicted with an accuracy of ≈102. On the basis of E, the electrophilic reactivities of diazonium ions can be compared with those of carbocations (Figure 9), and the combination with the nucleophilicity parameters N (Figure 10) gives a first clue on possible azo coupling reactions. Literature reports are discussed within this scheme. VCH Verlagsgesellschaft mbH, 1997.