反应详情

Commercially available 4-methoxyaniline can be treated with chlorosulfonyl isocyanate followed by aluminum chloride to give the corresponding 7-methoxy-1,1-dioxo-1,4-dihydro-2H-1λ6-benzo[1,2,4]thiadiazin-3-one. Opening of the cyclic urea with a strong acid (e.g., sulfuric acid) gives the desired 2-amino-5-methoxy-benzenesulfonamide intermediate.