2-Hydroxyimidazole → 1-[2-(3-Cyclopentyloxy-4-methoxy-phenyl)-2-oxo-ethyl]-1,3-dihydro-imidazol-2-one

Participants

Reaction Steps

Sodium bis(trimethylsilyl)amide (5 ml) was added to a solution of 1,3-dihydro-2H-imidazol-2-one (0.84 g) in DMF (50 ml), stirred under a N2 flow and cooled in an ice-bath. The reaction mixture was stirred for 30 minutes. Intermediate 1 (2.69 g) was added portionwise and the resulting reaction mixture was stirred for 16 hours at RT, then for 2 hours at 50° C. The reaction mixture was stirred in methyl isobutyl ketone/water (200 ml/50 ml). The solvent was evaporated and methyl isobutyl ketone (100 ml) was added and azeotroped on the rotary evaporator. The mixture was purified by column chromatography over silica gel (eluent: CH2Cl2 /(CH3OH/NH3) 97/3). The desired fractions were collected and the solvent was evaporated. The white solid was stirred in diisopropyl ether, filtered off, washed with DIPE and dried, yielding 0.4 g (12.6%) of 1-[2-[3-(cyclopentyloxy)-4-methoxyphenyl]-2-oxo-ethyl]-1,3-dihydro-2H-imidazol-2-one (interm. 2; mp. 201.1° C.).

Provenance & Evidence