1: 52.9 mg / toluene / 3.5 h / Heating 2: TFA / CH2Cl2 / 1.17 h / 0 - 20 °C 3: LiOH; H2O / methanol; tetrahydrofuran / 60 h / 20 °C 4: 6.4 mg / DIPEA; BOPCl / toluene / 37 h / 85 °C 5: CH2Cl2 / 0.67 h / 20 °C 6: K2CO3; MeOH / 1.5 h / 20 °C 7: 2.9 mg / aq. cerium ammonium nitrate / acetonitrile / 1 h / -10 °C View Scheme