Acetone → HCID 59372995, compound

Participants

Reaction Conditions

Reaction Steps

A suspension of 5-amino-1-(2-hydroxyphenyl)benzimidazole (4) (499 mg, 2.21 mmol), 80% propargyl bromide (2.43 mmol) in toluene (271 μL), K2CO3 (398 mg, 2.88 mmol), and acetone (15 mL) is stirred at 70° C. under argon for 18.5 h and then cooled to room temperature. The mixture is concentrated, diluted with H2O (35 mL), and extracted with ethyl acetate (100 mL and 50 mL). The extract is washed (brine) and dried. After solvent removal at reduced pressure, the residue is purified on silica gel (2% to 7% methanol/ethyl acetate) to give 213 mg (39%) of 5 as a light-brown solid, mp 40-42° C. IR 3379, 2966, 1512, 1239 cm−1; 1H NMR (CDCl3) δ 2.51 (t, J=2.4 Hz, 1H, C≡CH), 3.09 (bs, 2H, NH2), 4.68 (d, J=2.4 Hz, 2H, CH2C≡CH), 6.74 (dd, J=8.4 Hz, 2.1 Hz, 1H, 6-BenzimidH), 7.14 (d, J=8.4 Hz, 1H, 7-BenzimidH), 7.16 (d, J=2.1 Hz, 1H, 4-BenzimidH), 7.19 (m, 1H, 3-PhH), 7.29 (m, 1H, 5-PhH), 7.42-7.49 (m, 2H, 4,6-PhH), 8.01 ppm (s, 1H, 2-BenzimidH). HRMS calcd C16H13N3O [M+H]+ 264.1137. found 264.1129.

Provenance & Evidence