1: α-chymotrypsin / dimethylsulfoxide; H2O / 22 - 25 °C / potassium phosphate ( pH 7.0); with pig liver esterase the reaction rate is higher but the e.e. is lower 2: 1.) acyl azide formation, 2.) Curtius rearrangement 3: aq. HBr (48 percent) View Scheme