3-(Trifluoromethyl)phenyl isocyanate → 1-Prop-2-yn-1-yl-3-[3-(trifluoromethyl)phenyl]urea

Participants

Reaction Steps

A solution of propargyl amine (4.41 g, 5.13 mL, 80 mmol) in MeCN (30 mL) was added to a stirred solution of 3-(trifluoromethyl)phenyl isocyanate (15.0 g, 12.12 mL, 80 mmol) in MeCN (60 mL) under a nitrogen atmosphere. The reaction mixture was cooled with a RT cooling bath and the rate of addition was such that the internal temperature did not exceed 35° C. After 1.5 h the mixture was concentrated in vacuo. EtOAc (10 ml) was added to the residue and the mixture was sonicated for 2 minutes. The resultant slurry was diluted with cyclohexane (40 ml). The mixture was stirred for 10 minutes and the solid was then recovered by filtration. The mother liquors were concentrated in vacuo and the residue dissolved in EtOAc (10 mL). Dilution with cyclohexane (90 ml) precipitated a second batch of product which was recovered by filtration. The two batches were combined as an ethyl acetate solution and concentrated in vacuo to afford the title compound as a fawn solid (16.65 g).

Provenance & Evidence