合成路线1

Formylation of 2-methoxy-5-nitroaniline (I) with formic acid (II) in Ac2O/THF yields formamide (III), whose nitro group is then hydrogenated over Pd/C in MeOH to provide aniline (IV). Treatment of (IV) with pentafluorophenylsulfonyl chloride (V) in acetone in the presence of 2,6-lutidine affords sulfonamide (VI), which is then deformylated to hydrochloride (VII) by treatment with acetyl chloride and HCl in EtOH. The target compound is finally obtained by reaction of (VII) with potassium cyanate (KCNO) in H2O/HOAc. An analogous route can be also followed for the synthesis of the target product: Treatment of 3-nitro-4-fluoroaniline (VIII) with sodium methoxide (NaOMe) in refluxing MeOH furnishes 4-methoxy-3-nitroaniline (IX), which is then condensed with pentafluorophenylsulfonyl chloride (V) in MeOH to give sulfonamide (X). Reduction of the nitro moiety of (X) by hydrogenation over Pd/C in EtOH yields aniline (XI), which is finally treated with potassium cyanate (KCNO) in H2O/HOAc.