In the manufacture of sulfanilamide preparations the first stage is the preparation of an arylsulfanilic acid chloride. Of the various derivatives of arylsulfonyl chlorides [1] the N-acyl derivatives of sulfanilic acid are used most in industry. In the domestic pharmaceutical chemical industry N-carbomethoxysulfanilyl chloride, also known as phenylurethylansulfonyl chloride, (1%, is used exclusively. ... The process of preparing (I) is simple enough and consists of the interaction of N-carbomethoxyaniline ...