1-Chloro-4-methylphthalazine → 5-Amino-1-phenylbenzimidazole

Participants

Reaction Steps

A solution of 1-chloro-4-methylphthalazine (25 mg, 0.14 mmol) and 5-amino-1-(biphen-4-yl)benzimidazole (3) (28.5 mg, 0.10 mmol) in i-PrOH (2 mL) is stirred at 95° C. under argon for 2.5 h, cooled to room temperature, and concentrated at reduced pressure. The residue is diluted with sat. NaHCO3 (15 mL) and extracted with CHCl3 (60 mL). The extract is washed (brine) and dried. After solvent removal at reduced pressure, the residue is purified on silica gel (3.2% to 4.8% methanol/ethyl acetate) to give 38 mg (88%) of 4 (BI-3039) as a light-brown solid, mp 272-274° C. IR 3339, 2979, 1522, 1412 cm−1; 1H NMR (CD3OD/CDCl3) δ 2.82 (s, 3H, CH3), 7.36-7.53 (m, 3H, PhH), 7.62 (d, J=9.00 Hz, 1H, 7-BenzimidH), 7.69 (m, 2H, Aril, 2H PhH), 7.79 (d, J=8.7 Hz, 1H, 6-BenzimidH), 7.86 (d, J=8.1 Hz, 2H, ArH), 7.91-7.98 (m, 2H, 6,7-PhthH), 8.07 (m, 1H, 5-PhthH), 8.10 (s, 1H, 4-BenzimidH), 8.32 (s, 1H, 2-BenzimidH), 8.45 ppm (m, 1H, 8-PhthH).

Provenance & Evidence