A mixture trans-4-[8-amino-1-(4-phenoxyphenyl)-imidazo[1,5-a]pyrazin-3-yl]-cyclohexanecarboxylic acid (15.0 mg, 0.035 mmol), 2M of NH3 in i-PrOH (0.1 mL, 0.20 mmol), TBTU (22.5 mg, 0.070 mmol), DIEA (0.0647 mL, 0.371 mmol) and DMF (1 mL, 0.01 mol) was stirred at rt for 10 min. The reaction mixture was used for Gilson HPLC purification. The fractions containing the pure product were collected and concentrated in vacuo to afford the title compound as a yellow solid. 1H NMR (400 MHz, CDCl3): δ=1.63-1.76 (m, 2H), 1.78-1.90 (m, 2H), 2.08 (t, J=13.4 Hz, 4H), 3.00-3.10 (m, 1H) 6.94 (d, J=5.6 Hz, 1H), 7.10 (d, J=7.8 Hz, 2H), 7.15 (d, J=8.6 Hz, 2H), 7.20 (t, J=7.3 Hz, 1H), 7.36-7.44 (m, 3H), 7.58 (d, J=8.6 Hz, 2H). MS (ES+): m/z 427.96 (100) [MH+]. HPLC: tR=2.16 min (polar—5 min).
