Benzyl (S)-2-(1-bromo-8-hydroxyimidazo[1,5-a]pyrazin-3-yl)pyrrolidine-1-carboxylate ; (S)-Benzyl 2-(1-bromo-8-hydroxyimidazo[1,5-a]pyrazin-3-yl)pyrrolidine-1-carboxylate ;