2-(4-Isocyanatophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → N-[2-Methoxy-4-(trifluoromethyl)phenyl]-N′-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]urea

Participants

Reaction Steps

To a solution of 1 g of 2-methoxy-4-(trifluoromethyl)aniline and 128 mg of 4-dimethylaminopyridine in 150 mL of tetrahydrofuran and 1.5 mL of triethylamine are added, at 20° C., 1.28 g of 2-(4-isocyanatophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. After 4 hours, the reaction is evaporated to dryness under reduced pressure. The residue is taken up in a mixture of ethyl acetate and water. The organic phase is dried over magnesium sulfate and then concentrated under reduced pressure. The residual yellow oil is purified on a prepacked Biotage KP-Sil column of 60 Å SiO2 32-63 μm (eluent: 8/2 cyclohexane/ethyl acetate). A pale yellow powder is obtained, which is taken up in methanol. An insoluble white material is formed, which is separated out by filtration, and the filtrate is then evaporated to dryness under reduced pressure to give 0.47 g of a pale yellow powder of 1-(2-methoxy-4-trifluoromethylphenyl)-3-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]urea.

Provenance & Evidence