Hydrochloric Acid → 5-Methyl-1-[3-(trifluoromethyl)phenyl]-1,3-dihydro-2H-imidazol-2-one

Participants

Reaction Steps

A solution of 1-prop-2-yn-1-yl-3-[3-(trifluoromethyl)phenyl]urea (intermediate 1) (11.2 g, 46 mmol) in THF (60 mL) and acetonitrile (120 mL) was added, under a nitrogen atmosphere, to a stirred suspension of sodium hydride (60% dispersion in mineral oil) (4.62 g, 115 mmol) in THF (60 mL) at such a rate that gas evolution was not over-vigorous and the internal temperature remained below 30° C. The mixture was stirred at RT for 2.5 h, a thick precipitate having formed within 1 h. The reaction mixture was cautiously quenched with water (15 mL) and the resulting solution was treated with 1 M hydrochloric acid (150 mL, 150 mmol). The mixture was stirred for 4 hours then allowed to stand for 15 hours. Saturated brine (150 mL) was added and the phases were partitioned. The aqueous phase was extracted with EtOAc (100 mL). The combined organic phase was washed with saturated brine (100 mL), dried (sodium sulfate) and concentrated in vacuo. The residue was triturated with EtOAc (33 mL). The resultant solid was taken into DCM and filtered. The filtrate was concentrated in vacuo to afford the title compound (10.0 g) as a fawn solid.

Provenance & Evidence