Diisopropylethylamine → 2-(3-(2-(4-Fluorophenyl)-3-(methylcarbamoyl)benzofuran-5-yl)benzamido)-2-methylpropanoic acid

Participants

Reaction Steps

HATU (450 mg, 1.18 mmol) was added to a suspension of 3-(2-(4-fluorophenyl)-3-(methylcarbamoyl)benzofuran-5-yl)benzoic acid (400 mg, 1.03 mmol), methyl 2-amino-2-methylpropanoate hydrochloride (180 mg, 1.17 mmol), and DIPEA (0.6 mL, 3.4 mmol) in DCE (10 mL). After 5 min, the solids had not dissolved. Add DMF (0.5 mL) and continue stirring the suspension at r.t. overnight. The reaction was then concentrated to give a thick suspension (DMF remained after concentration). Water and Et2O were added and the flask swirled until a fine grey suspension was formed. The ppt. was collected by filtration, rinsed with 1 N HCl, water, and ether, and air dried to afford 550 mg (110% yield) of the title compound as a grey solid. LC/MS was performed on a Shimadzu-VP instrument with UV detection at 220 nm and Waters MICROMASS®. LC/MS method: solvent A=5% CH3CN/95% H2O/10 mM NH4OAc, solvent B=95% CH3CN/5% H2O/10 mM NH4OAc, start % B=0, sinal % B=100, gradient time=2 min, stop time=3 min, flow rate=5 ml/min, column: XBridge C18 5 μm 4.6×50 mm; HPLC Rt=1.49 min, (ES+) m/z (MH+)=489. To a suspension of the crude ester from above (˜0.1 mmol) in MeOH (7 mL)/H2O (2.1 mL) in a 20 mL scintillation vial with stir bar was added 10 N NaOH soln. (0.4 mL, 4.00 mmol). The vial was capped, stirred at r.t. overnight, then quenched by pouring into 8 mL of 1 N HCl. A white ppt. formed. The suspension was extracted with EtOAc, and the insoluble grey solid was collected by filtration and air dried (61 mg). The organic phase was washed with brine, dried over Na2SO4, filtered, and concentrated to give a white powder. This was triturated with Et2O and collected by filtration to give 360 mg of the white powder. Both crops of ppt. were identical by LC/MS and were combined to give 421 mg (86% over two steps) of the title compound as an off-white powder. 1H NMR (300 MHz, CD3OD) δ ppm 8.59 (s, 1H) 8.50 (d, J=3.29 Hz, 1H) 8.10-8.16 (m, 1H) 7.91-8.01 (m, 3H) 7.83 (dd, J=12.99, 7.87 Hz, 2H) 7.64-7.74 (m, 2H) 7.56 (t, J=7.68 Hz, 1H) 7.27 (t, J=8.78 Hz, 2H) 2.95-3.02 (m, 3H) 1.62 (s, 6H). LC/MS was performed on a Shimadzu-VP instrument with UV detection at 220 nm and Waters MICROMASS®. LC/MS method: solvent A=5% CH3CN/95% H2O/10 mM NH4OAc, solvent B=95% CH3CN/5% H2O/10 mM NH4OAc, start % B=0, final % B=100, gradient time=2 min, stop time=3 min, flow rate=5 ml/min, column: XBridge C18 5 μm 4.6×50 mm; HPLC Rt=1.06 min, (ES+) m/z (MH+)=475. Analytical HPLC were performed using a Shimadzu-VP instrument with UV detection at 220 nm and 254 nm. Analytical HPLC method: solvent A=5% CH3CN/95% H2O/0.1% TFA, solvent B=95% CH3CN/5% H2O/0.1% TFA, start % B=10, final % B=100, gradient time=15 min, stop time=18 min, flow rate=1 ml/min. Column: Waters Sunfire C-18, 3.5 μm 4.6×150 mm, Rt=10.91 min, purity=98%; column: Waters XBridge phenyl 3.5 μm 4.6×150 mm, Rt=10.21 min, purity=98%.

Provenance & Evidence