50779-86-7

Upstream product

• 108-31-6 maleic anhydride 
• 31419-01-9 dimethyl 3,3-diphenyl-3H-pyrazole-4,5-dicarboxylate 
• 908093-98-1 diazodiphenylmethane 
• 762-42-5 dimethyl acetylenedicarboxylate 

Downstream Products

• 53315-00-7 dimethyl 3,4-diphenyl-1H-pyrazole-1,5-dicarboxylate 
• 24567-08-6 3,4-diphenyl-1H-pyrazole 
• 50561-87-0 4,5-diphenyl-1⁽²⁾H-pyrazole-3-carboxylic acid methyl ester 
• 32258-63-2 4,5-diphenyl-1⁽²⁾H-pyrazole-3-carboxylic acid 

Relevant academic research and scientific papers

Rearrangements of 3H-Pyrazoles—Adducts of Dimethyl Acetylenedicarboxylate with Diphenyldiazomethane and 9-Diazofluorene

Structurally related 3H-pyrazoles resulting from 1,3-dipolar cycloaddition of diphenyldiazomethane and 9-diazofluorene to dimethyl acetylenedicarboxylate undergo van Alphen–Hüttel rearrangement on heating in a polar solvent (methanol, ethanol, acetic acid

Similarity and Differences in the Regioselectivities of Thermal and Acid-Catalyzed van Alphen–Hüttel Rearrangements in the Series of 3,3-Diphenyl-3H-pyrazoles Containing Electron-Withdrawing Substituents on C4 and C5

3,3-Diphenyl-3H-pyrazoles containing an electron-withdrawing substituent in the 5-position undergo van Alphen–Hüttel rearrangement with migration of one phenyl group to C4 on heating in an aprotic solvent (benzene, toluene), as well as on keepi

Regioselectivity of the thermal van Alphen–Hüttel rearrangement of 4- and 5-mono- and 4,5-disubstituted 3,3-diphenyl-3H-pyrazoles

Thermal van Alphen–Hüttel rearrangement of methyl 3,3-diphenyl-3H-pyrazole-4-carboxylate, 3,3-diphenyl-3H-pyrazole-4-carbonitrile, and methyl 5-methyl-3,3-diphenyl-3H-pyrazole-4-carboxylate involves completely regioselective migration of one phenyl group from the 3-position to N2with formation of aromatic 1H-pyrazole system. Thermal rearrangement of methyl 3,3-diphenyl-3H-pyrazole-5-carboxylate leads to the formation of methyl 4,5-diphenyl-1H-pyrazole-3-carboxylate as a result of migration of the 3-phenyl group exclusively to the C4atom and subsequent prototropic isomerization. Under analogous conditions, methyl 4-methyl-3,3-diphenyl-3H-pyrazole-5-carboxylate, methyl 5-(methanesulfonyl)-3,3-diphenyl-3H-pyrazole-4-carboxylate, methyl 5-(benzenesulfonyl)-3,3-diphenyl-3H-pyrazole-4-carboxylate, and dimethyl 3,3-diphenyl-3H-pyrazole-4,5-dicarboxylate have been regioselectively converted into the corresponding 4H-pyrazoles. Thermolysis of 5-(4-methylbenzenesulfonyl)-3,3-diphenyl-3H-pyrazole-4-carbonitrile gives rise to a mixture of 1H- and 4H-pyrazoles, the former considerably prevailing, whereas the corresponding 1H-pyrazoles are formed as the only product from 5-(methanesulfonyl)- and 5-(benzenesulfonyl)-3,3-diphenyl-3H-pyrazole-4-carbonitriles.