Methanesulfonic Acid → Benzyl 3-aminobutan-2-ylcarbamate

Participants

Reaction Steps

To a mixture of butane-2,3-diamine (4.8 g, 54.5 mmol) in water (50 mL) containing bromocresol green as indicator was slowly added a solution of methane sulfonic acid (10.46 g) in water (50 mL) until a blue to yellow color transition was observed. The mixture was diluted with ethanol (100 mL) and to it was added a solution of Cbz-Cl (7.61 g, 45.5 mmol) in DME (50 mL) and aqueous AcOK (w/v=50%) to maintain the pale-green color. The reaction mixture was stirred (RT, 1 h), concentrated under reduced pressure, treated with water and filtered. The solution was washed with toluene, basified with 40% aqueous NaOH and extracted with toluene (4×100 mL). The combined organic layers were washed with brine, dried over MgSO4, filtered and concentrated under reduced pressure to afford benzyl 3-aminobutan-2-ylcarbamate (4.2 g, 35%) as a colorless oil. Mass calculated for C12H18N2O2=222.28. found: [M−H]+=221.2.

Provenance & Evidence