1: 3 N NaOH / H2O / 2 h / Heating 2: 88 percent / formic acid, concd. HCl / H2O / 6 h / Heating 3: 73 percent / thionyl chloride / methanol 4: 36 percent / α-chymotrypsin / H2O; aq. HCl; NaCl / 60 h / 20 °C 5: 61 percent / acetic acid / 1.) RT, 24 h; 2.) 90 deg C, 3 h View Scheme

1: 3 N NaOH / H2O / 2 h / Heating 2: 88 percent / formic acid, concd. HCl / H2O / 6 h / Heating 3: 73 percent / thionyl chloride / methanol 4: 36 percent / α-chymotrypsin / H2O; aq. HCl; NaCl / 60 h / 20 °C 5: 61 percent / acetic acid / 1.) RT, 24 h; 2.) 90 deg C, 3 h View Scheme