149990-27-2

6089-09-4

75-65-0

149990-27-2

General procedure for the synthesis of N-Boc-butyn-4-amine from 4-pentynoic acid and tert-butanol: To a solution of 4-pentynoic acid (1.96 g, 20 mmol) in tert-butanol (6 mL) was added triethylamine (3 mL) at 0 °C, followed by the slow addition of diphenylphosphoryl azide (note: the reaction will start rapidly and may proceed violently after addition). The reaction mixture was heated to 85 °C and kept overnight under nitrogen protection. Upon completion of the reaction, the solvent was removed by vacuum concentration and the crude product was purified by silica gel column chromatography using dichloromethane as eluent to give N-Boc-butyn-4-amine as a white solid (1.81 g, 53% yield).