A solution of 4,5-diisopropylfuran-2-carboxylic acid (50 mg, 0.255 mmol) and cyanuric chloride (71 mg, 0.385 mmol) in acetone (3 ml) was added with triethylamine (142 μl, 1.021 mmol), and the mixture was stirred at room temperature for 3.5 hours. The reaction mixture was added with methyl 4-aminobenzoate (77 mg, 0.510 mmol), and the mixture was further stirred for 14 hours. The reaction solvent was evaporated, then the residue was dissolved in pyridine (1 ml), the solution was added with 4-dimethylaminopyridine (1 mg, 8.20 μmol), and the mixture was stirred at room temperature for 4 hours. Pyridine was evaporated, and then the reaction mixture was dissolved in 10% methanol-chloroform, the solution was added with silica gel (1.0 g), and the mixture was evaporated to dryness. The residue was purified by silica gel chromatography [hexane-ethyl acetate (6:1)] to obtain methyl 4-[(4,5-diisopropylfuran-2-carbonyl)amino]benzoate (75 mg, 89%) as colorless prisms.
