The sulfonation of 3-aminobenzonitrile (I) with benzenesulfonyl chloride (II) by means of triethylamine in dichloromethane gives the sulfonamide (III), which is nitrated with HNO3 in acetic anhydride yielding 4-nitro-3-(phenyl sulfonamido)benzonitrile (IV). The reduction of (IV) with SnCl2 in hot ethanol affords the corresponding 4-amino derivative (V), which is finally condensed with 2-bromophenyl isocyanate (VI) in hot DMF.

The sulfonation of 3-aminobenzonitrile (I) with benzenesulfonyl chloride (II) by means of triethylamine in dichloromethane gives the sulfonamide (III), which is nitrated with HNO3 in acetic anhydride yielding 4-nitro-3-(phenyl sulfonamido)benzonitrile (IV). The reduction of (IV) with SnCl2 in hot ethanol affords the corresponding 4-amino derivative (V), which is finally condensed with 2,3-dichlorophenyl isocyanate (VI) in hot DMF.