Scheme 2.

Synthesis of dimethyl 2′′,2′′′-[6′-(4-sulfamoylphenylamino)-1′,3′,5′-triazine-2′,4′-diyl]-bis(azanediyl)diacetate intermediate 2. Reagents and conditions: a mixture of methyl 2-aminoacetate hydrochloride, DMF, and DIPEA was stirred for 2 h at r.t. Then, 4-(4′,6′-dichloro-1′,3′,5′-triazin-2′-ylamino)-benzene-sulfonamide 1 dissolved DMF was added, and the mixture was stirred at 90 °C under an argon atmosphere overnight. Product yield: 37%.