Hydrochloric Acid → 5-Amino-2,1-benzoxaborol-1(3H)-ol

Participants

Reaction Steps

To a solution of 5-nitrobenzo[c][1,2]oxaborol-1(3H)-ol (CII) (360 mg, 2.01 mmol) in MeOH (25 mL) was added Zn dust (1.31 g, 20.11 mmol) and 2 M HCl (30 mL, 60.33 mmol). The reaction mixture was stirred at room temperature for 2.5 h before saturating with 5% aq. NaHCO3 (40 mL). The solids were filtered and filtrate was concentrated under reduce pressure to about 50 mL. The residue was diluted with EtOAc and the phases were separated. The organic layer was washed with brine, dried over MgSO4, and concentrated in vacuo to give 5-aminobenzo[c][1,2]oxaborol-1(3H)-ol (CIII) as a brown oil (250 mg, 1.68 mmol, 83% yield, 80% purity). ESIMS found for C7H8BNO2 m/z 149.9 (M+H). The crude product was used without further purification for coupling.

Provenance & Evidence