Nitration of 4-methylisoquinoline (I) with KNO3 in H2SO4 provided the 5-nitro derivative (II). Subsequent catalytic hydrogenation of the nitro group of (II) gave amine (III). Diazotization of (III), followed by treatment with SO2 and CuCl2, generated the sulfonyl chloride (IV). This was condensed with 4-Boc-2-methyl-perhydro-1,4-diazepine (V) to furnish the sulfonamide (VI). The Boc protecting group of (VI) was finally cleaved using HCl in aqueous EtOH.