The present application relates to a process based on the oxidative ring opening of a compound with oxindole structure for preparation of substituted 2-(triazinylcarbonyl)sulfonanilides of the formula (1-1) proceeding from N-sulfonyl-substituted 3-triazinyloxindole of the formula (2-1), and to the 2-(triazinylcarbonyl)sulfonanilides of the formula (1-1) thus prepared, and to the use thereof as intermediates for the synthesis of fine chemicals and of active ingredients in the agricultural sector. The invention also relates to a multistage process for preparation of N-alkyl-N-[2-(1,3,5-triazin-2-ylcarbonyl)phenyl]alkanesulfonamides of the formula (4-1), proceeding from a 3-(alkylsulfanyl)-1,3-dihydro-2H-indol-2-one of the formula (7-1), wherein the multistage process also comprises, as a component step, the oxidative ring opening mentioned, and to the 2-(triazinylcarbonyl)sulfonanilides of the formula (1-1) which are obtained by the oxidative ring opening and are used as intermediates in the multistage process.本発明は、オキシインドール類を選択的にＮ－スルホニル化する方法、特に、３－トリアジニルオキシインドール類をＮ－スルホニル化する方法、Ｎ－スルホニル－置換３－トリアジニルオキシインドール類、並びに、精密化学製品並びに医薬分野及び農業分野における活性物質を合成するための中間体生成物としてのＮ－スルホニル－置換オキシインドール類及びＮ－スルホニル－置換３－トリアジニルオキシインドールの使用、並びに、農業分野における活性物質としての前記化合物の使用に関する。
