Diisopropylethylamine (DIPEA, 0.23 ml, 1.3 mM) then 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide (EDC, 126 mg, 0.66 mM) were added to a solution of 2-dimethylaminoethylamine (0.57 ml, 0.53 mM) and 6-{[3,5-Di-(benzyloxy)benzoyl]amino}nicotinic acid (0.20 g, 0.44 mM) in dichloromethane (10 ml) under argon at ambient temperature. After 16 hours the reaction mixture was evaporated in vacuo and then chromatographed on SiO2 using a gradient elution of 10 to 25% methanol in dichloromethane. The fractions containing product were evaporated to give a cream solid (0.052 g, 25%); 1H NMR δ (d6-DMSO): 2.67 (6H, s); 3.11 (2H, m); 3.62 (2H, m); 5.18 (4H, s); 6.88 (1H, s); 7.27-7.52 (12H, br m); 8.18-8.36 (2H, m); 8.90 (1H, s); 10.20 (1H, br s).
