Method B. N, N4-Ble (3-azidobutyryl)-l, 4-diaminobutane (16, 239 mg, 0.765 mmol) was added to a 25-mL round-bottom flask followed by attachment of a reflux condenser. THF (5 mL) was added via syringe, dissolving all the solid. BH3. THF solution (1.0 M, 9.18 mL, 9.18 mmol) was slowly added and the resulting mixture was brought to reflux temperature for 24 h. After this time, the mixture was stirred at room temperature for 6 h. An ice bath was used ...