Boron tribromide → HCID 59373055, compound

Participants

Reaction Steps

A solution of 5-amino-1-(2-methoxyphenyl)benzimidazole (3) (829 mg, 3.46 mmol), 1.0 M boron tribromide (10 mmol) in dichloromethane (10 mL), and dichloromethane (35 mL) is stirred under argon for 4 h, quenched with sat. NaHCO3 (55 mL), and extracted with ethyl acetate (150 mL, 100 mL, and 50 mL). The extract is washed (brine) and dried. After solvent removal at reduced pressure, the crude material is washed (dichloromethane) to give 604 mg (78%) of 4 as a brown solid, mp 202-203° C. IR 3346, 2956, 1512, 1256 cm−1; 1H NMR (DMSO-d6) δ 5.18 (bs, 2H, NH2), 6.65 (d, J=8.4 Hz, 1H, 6-BenzimidH), 6.90 (s, 1H, 4-BenzimidH), 6.99 (d, J=8.4 Hz, 1H, 7-BenzimidH), 7.02 (d, J=7.8 Hz, 1H, 3-PhH), 7.13 (d, J=7.8 Hz, 1H, 5-ArH), 7.32 (d, J=7.8 Hz, 1H, 4-PhH), 7.38 (d, J=7.8 Hz, 1H, 6-PhH), 8.13 (s, 1H, 2-BenzimidH), 10.15 ppm (s, 1H, OH). HRMS calcd C13H11N3O [M+H]+ 226.0975. found 226.0975.

Provenance & Evidence