Claisen condensation between diethyl phthalate (I) and diethyl succinate (II) in the presence of NaOEt gives rise to the naphthalenedicarboxylate (III). Alkylation of the phenolic hydroxyl groups of (III) with iodoethane under Williamsom's ether synthesis conditions furnishes the diethoxy napthalenedicarboxylate (IV). Then, alkaline hydrolysis of diester (IV) affords diacid (V), which is further converted to the cyclic anhydride (VI) upon treatment with SOCl2. Condensation of anhydride (VI) with ethyl p-aminophenylacetate (VII) in boiling AcOH leads to the cyclic imide (VIII). Partial reduction of (VIII) with Zn/AcOH produces lactam (IX). The ethyl ester group of (IX) is then selectively hydrolyzed under alkaline conditions to furnish acid (X). Finally, CDI-mediated coupling of acid (X) with benzesulfonamide yields the target N-acyl sulfonamide.

Claisen condensation between diethyl phthalate (I) and diethyl succinate (II) in the presence of NaOEt gives rise to the naphthalenedicarboxylate (III). Alkylation of the phenolic hydroxyl groups of (III) with iodoethane under Williamsom's ether synthesis conditions furnishes the diethoxy napthalenedicarboxylate (IV). Then, alkaline hydrolysis of diester (IV) affords diacid (V), which is further converted to the cyclic anhydride (VI) upon treatment with SOCl2. Condensation of anhydride (VI) with ethyl p-aminophenylacetate (VII) in boiling AcOH leads to the cyclic imide (VIII). Partial reduction of (VIII) with Zn/AcOH produces lactam (IX). The ethyl ester group of (IX) is then selectively hydrolyzed under alkaline conditions to furnish acid (X). Finally, CDI-mediated coupling of acid (X) with benzesulfonamide yields the target N-acyl sulfonamide.