Water → HCID 86672708, compound

Reaction equation

C[O:2][CH:3](OC)[CH2:4][N:5]1[C:9]2[C:10]([C:14]([O:16][CH3:17])=[O:15])=[CH:11][CH:12]=[CH:13][C:8]=2[N:7]=[C:6]1[CH:18](C)C.O.FC(F)(F)C(O)=O>C(Cl)Cl>[CH3:18][C:6]1[N:5]([CH2:4][CH:3]=[O:2])[C:9]2[C:10]([C:14]([O:16][CH3:17])=[O:15])=[CH:11][CH:12]=[CH:13][C:8]=2[N:7]=1

Participants

Procedure

To a stirred solution of methyl 1-(2,2-dimethoxyethyl)-2-isopropyl-1H-benzo[d]imidazole-7-carboxylate from Step A above in methylene chloride were added water and trifluoroacetic acid and the reaction was stirred at room temperature for 2 h and then heated at reflux for 3.5 h. The reaction mixture was concentrated under reduced pressure to remove the excess trifluoroacetic acid, diluted with methylene chloride, washed with saturated aqueous sodium bicarbonate, re-extracted with methylene chloride, dried (Na2SO4), filtered, and concentrated under reduced pressure to give methyl 2-methyl-1-(2-oxoethyl)-1H-benzo[d]imidazole-7-carboxylate (0.4 g, 56%): 1H NMR (500 MHz, DMSO-d6) δ 9.70 (s, 1H), 7.81 (dd, J=8.0, 1.5 Hz, 1H), 7.67 (dd, J=7.5, 1.0 Hz, 1H), 7.25 (t, J=8.0 Hz, 1H), 5.38 (s, 2H), 3.84 (s, 3H), 2.47 (s, 3H); MS (ESI+) m/z 233 (M+H).