Sulfuric Acid → 2H-1,4-Benzoxazine-2,3(4H)-dione

Participants

Reaction Steps

14.7 parts of isatin are introduced into a suspension of 29 parts of potassium peroxydisulfate in 280 parts of 30% strength sulfuric acid at room temperature. The reaction mixture is then stirred for 24 hours without cooling, after which it is poured into water. The product is filtered off and dried, giving 11 parts of 2,3-dioxo-1,4-benzoxazine, of melting point 279°-283° C. (with decomposition).

Provenance & Evidence