Reaction Steps
A solution of 71 (60 mg, 0.095 mmol) and TFA (5 mL) in DCM (20 mL) was stirred at RT for 5 h. The TFA was removed by co-evaporation with DCM and MeOH, diluted with water, and the pH was adjusted to around 12 with 1N NaOH. The resultant gel was extracted with DCM with traces of MeOH. The combined organic extract was dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was purified by Biotage (SNAP 10 g column; 2% of ammonium hydroxide in MeOH/DCM; 0/100 to 10/90 over 20 CV, 10/90 to 20/80 over 10 CV then 20/80 over 5 CV), to afford the title compound 72 (35 mg, 0.066 mmol, 69% yield, traces of TFA) as a white sticky solid. 1H NMR (400 MHz, DMSO-d6) δ (ppm) 8.72 (s, 1H), 8.55 (d, J=1.8 Hz, 1H), 8.52 (d, J=5.3 Hz, 1H), 8.35 (s, 1H), 8.26 (d, J=8.0 Hz, 1H), 7.83 (dd, J=8.2, 2.2 Hz, 1H), 7.73 (dd, J=13.6, 2.4 Hz, 1H), 7.38 (t, J=9.1 Hz, 1H), 7.20 (dd, J=8.9, 1.5 Hz, 1H), 6.65 (dd, J=5.3, 0.6 Hz, 1H), 6.58 (bd, J=2.7 Hz, 1H), 4.59 (s, 2H), 3.37 (s, 2H), 3.28 (t, J=5.5 Hz, 2H), 2.95 (t, J=5.4 Hz, 2H), 2.59-2.51 (m, 1H), 0.72-0.58 (m, 2H), 0.50-0.36 (m, 2H), one NH is missing. MS (m/z): 533.4 (M+H).
