To a solution of 3,5-diamino-6-chloro-pyrazine-2-carboxylic acid (161 mg, 0.86 mmol) and HATU (325 mg, 0.86 mmol) in DMF (10 mL) is added N-methylmorpholine (0.38 mL, 3.42 mmol) followed by N*2*-(2,4-dimethoxy-benzyl)-5-[4-((R)-2,2-dimethyl-[1,3]dioxolan-4-ylmethoxy)-phenyl]-pentane-1,2-diamine (391 mg, 0.86 mmol) and the mixture is stirred at RT overnight. The solvent is removed in vacuo. To the crude residue is added water (10 mL), which is then decanted off to leave an orange solid that is washed with diethyl ether (10 mL) and dried in vacuo at 50° C. to afford the title compound. [M+H]+ 629.
