The invention relates to methods for producing sulfonamides of formula I, wherein the variables have the designations cited in the description, by reacting m-nitro-benzoic acid chlorides of formula II with aminosulfons of formula III, under the influence of B equivalents of base IV. Said method is characterised in that, during step a) the aminosulfon of formula III is reacted with B1 equivalents of base IV, and during step b), the reaction mixture resulting from step a) is reacted with m-nitro-benzoic acid chlorides of formula II and B2 equivalents of base IV; B, B1 and B2 having the designations cited in the description.