A process for the preparation of a 2,3-dioxo-1,4-benzoxazine derivative of the formula I ##STR1## where R.sup.1 and R.sup.2 are identical or different and each is hydrogen, alkyl, halogen, haloalkyl, alkoxy, haloalkoxy or nitro, by oxidizing an isatin of the formula II ##STR2## where R.sup.1 and R.sup.2 have the above meanings, with a peroxydisulfate dissolved or suspended in 30-98% strength sulfuric acid. The 2,3-dioxo-1,4-benzoxazine derivatives obtainable by the novel process have fungicidal or fungistatic properties.
一种制备公式I的2,3-二氧代-1,4-苯并噁嗪衍
生物的方法,其中R1和R2相同或不同,且均为氢、烷基、卤素、卤代烷基、烷氧基、卤代烷氧基或硝基,通过将公式II的
吲哚酮(其中R1和R2具有上述含义)与溶解或悬浮在30-98%浓度
硫酸中的过二
硫酸盐氧化。通过新方法获得的2,3-二氧代-1,4-苯并噁嗪衍
生物具有杀真菌或抑菌作用。