To a stirred solution of 3-(3,5-dibromo-2-oxo-2H-pyrazin-1-yl)-4-methyl-benzoic acid, methyl ester (Example 1b, 0.2 g) in tetrahydrofuran (3 mL) within a microwave vial was added triethylamine (76 μL) and benzylamine (64 mg). The reaction was stirred overnight before the addition of cyclopropylamine (0.22 mL) and iso-propylmagnesium chloride (2M in tetrahydrofuran, 1.5 mL) dropwise. After stirring for 30 minutes, ethanol (2 mL), formic acid (0.4 mL) and 10% palladium on carbon (30 mg) were added. The reaction mixture was heated within a microwave for 60 minutes at 110° C. before being cooled to room temperature, filtered and washed with ethanol. The filtrate was concentrated in vacuo. Purification by preparative HPLC (Gemini column, 0.1% ammonia: acetonitrile eluent) afforded the title compound (80 mg).
