7791-48-2

Upstream product

• 52200-09-6 2-benzoyl-3-(dimethylamino)-2-propenenitrile 
• 100-63-0 phenylhydrazine 
• 59-88-1 phenylhydrazine hydrochloride 
• 614-16-4 Benzoylacetonitrile 
• 4637-24-5 N,N-dimethyl-formamide dimethyl acetal 
• 532-27-4 1-chloroacetophenone 
• 174652-94-9 1-phenyl-2-cyano-3-dimethylaminopropen-1-one 

Relevant academic research and scientific papers

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.

Aqueous one-pot synthesis of pyrazoles, pyrimidines and isoxazoles promoted by microwave irradiation

Microwave irradiation promotes the conversion of enaminoketones formed in situ into a variety of heterocycles by reaction with the appropriate bidentate nucleophile. The advantages of the method over previous approaches are short reaction times and facile purification by precipitation of the products in aqueous media. Moreover the convenient one-pot procedure makes these syntheses particularly suitable for library production. Organic reactions in aqueous media have become of great interest as water is not only more environmentally friendly, but also because organic reactions in water often display unique reactivity and selectivity.

Cyanoacetophenone as a synthon for 1,4,5-substituted pyrazoles

An improved synthesis of cyanoacetophenone is described. Cyanoacetophenone was reacted with dimethylformamide-dimethylacetal and diphenylformamidine to give 1-dimethylamino-3-oxo-3-phenyl-1-propene-2-carbonitrile and 1-anilinomethylene-3-oxo-3-phenyl-1-propene-2-carbonitrile. Reaction of 1-dimethylamino-3-oxo-3-phenyl-1-propene-2-carbonitrile with hydrazines gave either 1-substituted 5-amino-4-benzoylpyrazoles or (1-substituted) 4-cyano-5-phenylpyrazoles. Treatment of 1-anilinomethylene-3-oxo-3-phenyl-1-propene-2-carbonitrile with phenylhydrazine also yielded 5-amino-4-benzoyl-1-phenylpyrazole, whereas reaction with unsubstituted hydrazine afforded 4-cyano-5-phenylpyrazole.

Steric and electronic control in the addition of hydrazine and phenylhydrazine to α-[(dimethylamino)methylene]-β-oxoarylpropanenitriles

Reaction of hydrazine with α-[(dimethylamino)methylene]-β-oxoarylpropanenitriles 2 gives a mixture of the 4-aroyl-5-aminopyrazoles 3 and the 5-aryl-4-cyanopyrazoles 4. Similarly reaction of 2 with phenylhydrazine gives rise to the 5-amino-4-aroyl-1-phenylpyrazoles 5 and 5-aryl-4-cyano-1-phenylpyrazoles 6. The regioselectivity of addition has been investigated with respect to the electronic nature and steric requirements of the aromatic substitution. The ratio of products was found to be independent of the electronic nature of the substituent. The outcome of the reaction was however very sensitive to steric factors. Substituents in the para- and meta-positions favoured formation of the pyrazole-nitrile products 4 and 6, whereas sterically demanding ortho-substituents favoured the pyrazole-amino ketones 3 and 5.