1: 88 percent / formic acid, concd. HCl / H2O / 6 h / Heating 2: 73 percent / thionyl chloride / methanol 3: 36 percent / α-chymotrypsin / H2O; aq. HCl; NaCl / 60 h / 20 °C 4: 61 percent / acetic acid / 1.) RT, 24 h; 2.) 90 deg C, 3 h View Scheme

1: 88 percent / formic acid, concd. HCl / H2O / 6 h / Heating 2: 73 percent / thionyl chloride / methanol 3: 36 percent / α-chymotrypsin / H2O; aq. HCl; NaCl / 60 h / 20 °C 4: 61 percent / acetic acid / 1.) RT, 24 h; 2.) 90 deg C, 3 h View Scheme

Multi-step reaction with 2 steps 1: 88 percent / formic acid, concd. HCl / H2O / 6 h / Heating2: 73 percent / thionyl chloride / methanol