Ethyl isocyanate → 1-[3-cyclopentyl-2(R)-(3,4-dichloro-phenyl)-propionyl]-3-ethyl-urea

Participants

Reaction Steps

A solution of 3-cyclopentyl-2(R)-(3,4-dichloro-phenyl)-propionamide (prepared in Example 13, 103 mg, 0.36 mmol) in toluene (10 mL) was treated with ethyl isocyanate (40 μL, 0.54 mmol). The resulting reaction mixture was heated under reflux for 24 h. The reaction mixture was then concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 4/1 hexanes/ethyl acetate) afforded 1-[3-cyclopentyl-2(R)-(3,4-dichloro-phenyl)-propionyl]-3-ethyl-urea (54 mg, 42%) as a white foam: [α]23589=−41.9° (c=0.031, chloroform); FAB-HRMS m/e calcd for C17H22Cl2N2O2 (M+H)+357.1136, found 357.1137.

Provenance & Evidence