2,2,2-Trifluoroethanol → 9-Chloro-6-[cyclopropyl(2,2,2-trifluoroethoxy)methyl]-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazole

Participants

Reaction Steps

To a solution of [9-chloro-1-(2,4-dichlorophenyl)-1,2,3,4-tetrahydropyrimido[1,2-a]benzimidazol-6-yl](cyclopropyl)methanol (150 mg, 0.355 mmol), 1,1′-(azodicarbonyl)dipiperdine (179 mg, 0.709 mmol) in tetrahydrofuran (7.5 mL) was added tri(n-butyl)phosphine (0.177 mL, 0.709 mmol) at room temperature. After the mixture was stirred at room temperature for 10 min under nitrogen atmosphere, 2,2,2-trifluoroethanol (0.259 mL, 3.55 mmol) was added to the reaction mixture. The mixture was stirred at 65° C. for 15 hr under nitrogen atmosphere. The mixture was concentrated in vacuo and diethyl ether was added to the residue. The solid was removed by filtration and the filtrate was concentrated in vacuo. The residue was purified by flash chromatography on silica gel eluting with a 10-30% ethyl acetate/n-hexane gradient mixture and recrystallization from 2-propanol/n-hexane to give the title compound (102.9 mg, 0.204 mmol, 57%) as colorless crystals.

Provenance & Evidence