Step F (1): Methyl 3-(butyl(methyl)carbamoyl)benzoate. To a solution of 3-(methoxycarbonyl)benzoic acid (1.8 g, 10 mmol) in dichloromethane (40 mL) and DMF (20 mL) was added Hunig's base (2.58 g, 20 mmol) to make a clear solution and HATU (4.18 g, 11 mmol) was then added. After stirring for 10 min, the reaction mixture was added methylbutylamine (1.13 g, 13 mmol) and the reaction mixture was stirred at rt for 3 h. Dichloromethane was removed and ethyl acetate (300 mL) was added and the mixture was washed with 1N HCl, sodium carbonate solution, H2O, dried and concentrated to give the title compound ready for next step without purification: 1H NMR (CDCl3, 500 MHz) δ 0.79-0.98 (3H, m), 1.15 (1H, m), 1.41 (1H, brd s), 1.52 (1H, brd s), 1.64 (1H, m), 2.92-3.07 (2H, m), 3.21 (1H, brd s), 3.53 (1H, brd s), 3.91 (3H, s), 7.47 (1H, m), 7.58 (1H, d, J=10 Hz), 8.05-8.07 (2H, m).
