Reaction of 1,2-Diarylhydrazines with Acetic Anhydride Catalyzed by 4-(Dimethylamino)pyridine

Article abstract of DOI:10.1007/BF00809807

A new method for the synthesis of 1,2-diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-ones 3 and 4-acetyl-1,2-diaryl-1,2-dihydro-5-methyl-3-H-pyrazol-3-ones 5 is presented.The reaction of 4,4'-disubstituted 1,2-diarylhydrazines 1 with acetic anhydride in the presence of an equimolar amount of 4-(dimethylamino)pyridine leads to mixtures of the corresponding acetyl derivatives 2 and 3.Under the same conditions, 2,2'-disubstituted 1,2-diarylhydrazines yield mixtures of 3 and 5. Keywords.Catalysis by 4-(Dimethylamino)pyridine; 1,2-Diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-ones; 4-Acetyl-1,2-diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-ones.