To a solution of tert-butyl 4-((methylamino)methyl)thiazol-2-ylcarbamate (Intermediate 17, 1.30 g, 5.3 mmol) and 3-methylpyrazine-2-carboxylic acid (1.1 g, 8 mmol) in CH2Cl2 (25 mL) was added DCC (1.64 g, 8 mmol). The mixture was stirred for 2 hours and the solids were removed by filtration. The filtrate was concentrated in vacuo and purified by column chromatography (2% MeOH in CH2Cl2, Rf=0.15) to afford tert-butyl 4-((N,2-dimethylpyrazine-3-carboxamido)methyl)thiazol-2-ylcarbamate (1.30 g, 3.6 mmol) as an off-white solid in 68% yield.
