The present invention relates to a process for the preparation of sulphonamide-substituted imidazotriazinones of the general formula (I) ##STR1##

characterized in that compounds of the formula (II) ##STR2##

are reacted with sulphuric acid and the products obtained are then reacted with thionyl chloride and converted in situ in an inert solvent using an amine into the compounds according to the invention and, if appropriate, reacted to give the corresponding salts, hydrates or N-oxides.