Multi-step reaction with 2 steps 1: 74 percent / (CF3CO)2O, (CH3CO)2O, s-collidine / 3-4 deg C, 30 min then 35 deg C, 108 h; repeated addition of reagents2: 51 percent / HCl / methanol; H2O / 3.5 h / 70 °C  

Multi-step reaction with 2 steps 1: 77 percent / (CF3CO)2O, (CH3CO)2O, s-collidine / 3-4 deg C, 30 min then 35 deg C, 24 h; repeated addition of reagents2: 51 percent / HCl / methanol; H2O / 3.5 h / 70 °C