To a stirred mixture of 2-bromo-N-tert-butyl-5H-pyrrolo[3,2-b]pyrazine-7-carboxamide in DMF (5 mL) was added chloromethyl pivalate (225 mg, 1.5 mmol) followed by K2CO3 (276 mg, 2 mmol). The mixture was stirred at room temperature for 16 hours. The mixture was poured into water and extracted with EtOAc (3×10 mL). The combined organic layers were washed with brine and dried over Na2SO4. After filtration and concentration, the residue was purified by column chromatography on silica gel eluting with petroleum ether/EtOAc (5:1, v/v) to give (2-bromo-7-(tert-butylcarbamoyl)-5H-pyrrolo[3,2-b]pyrazin-5-yl)methyl pivalate (140 mg, 34% over two steps) as white solid. MS: (M+H)+=411; 1H NMR (300 MHz, CDCl3): δ 8.41 (s, 1H), 8.33 (s, 1H), 7.80 (s, 1H), 6.20 (s, 2H), 1.52 (s, 9H), 1.15 (s, 9H).
