Brønsted Acid-Catalyzed Addition Reaction of 5-Aminopyrazoles with 4-Aryl-1,2,4-triazole-3,5-diones

Abstract An organocatalytic addition reaction of 5-aminopyrazole with 4-aryl-1,2,4-triazole-3,5-dione has been developed. Using 20 mol% of diphenyl phosphate as the catalyst, moderate to high yields are obtained for a variety of aminopyrazole-embedded 1,2,4-triazolidine-3,5-diones (urazoles) under mild reaction conditions.