hydrogen bromide in water T=120°C; 4 h; Product distribution / selectivity;

water; hydrogen bromide T=120°C; 5 h; Product distribution / selectivity;

water; hydrogen bromide T=105°C; 17 h; Product distribution / selectivity;

water; hydrogen bromide T=105°C; 17 h; Product distribution / selectivity;

potassium hydroxide; porcine kidney acylase I pH 7.5-8.0; Yields of byproduct given;

1: NaH / tetrahydrofuran / 0 - 25 °C 2: 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 3: 1.) acyl azide formation, 2.) Curtius rearrangement 4: aq. HBr (48 percent) View Scheme

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

1.1: water; methanol / 20 h / 40 °C / Sealed tube 2.1: sulfuric acid / dichloromethane; water / 3.25 h / -10 - 0 °C / Cooling with ice 2.2: pH 8 - 9 3.1: ammonium formate / palladium on carbon / isopropyl alcohol / 1 h / Inert atmosphere; Reflux 4.1: water; hydrogen bromide / methanol / 100 °C / 15 - 22.5 Torr 5.1: water; hydrogen bromide / 17 h / 105 °C View Scheme

1.1: sulfuric acid / dichloromethane; water / 3.25 h / -10 - 0 °C / Cooling with ice 1.2: pH 8 - 9 2.1: ammonium formate / palladium on carbon / isopropyl alcohol / 1 h / Inert atmosphere; Reflux 3.1: water; hydrogen bromide / methanol / 100 °C / 15 - 22.5 Torr 4.1: water; hydrogen bromide / 17 h / 105 °C View Scheme

1: ammonium formate / palladium on carbon / isopropyl alcohol / 1 h / Inert atmosphere; Reflux 2: water; hydrogen bromide / methanol / 100 °C / 15 - 22.5 Torr 3: water; hydrogen bromide / 17 h / 105 °C View Scheme