Reaction Steps
To a solution of N-((3S,7R,8R,9S)-7-(2-fluoroethyl)-8-isobutoxy-9-methyl-2-oxooxonan-3-yl)-3-hydroxy-4-methoxypicolinamide (97 mg, 0.220 mmol) in anhydrous acetone (2.2 mL) were added powdered K2CO3 (60.9 mg, 0.440 mmol) and bromomethyl acetate (32.4 μl, 0.330 mmol). The resulting mixture was heated to 50° C. and stirred vigorously for 16 h, then filtered through a plug of Celite®, concentrated, and purified by column chromatography on SiO2 (5→50% acetone/hexanes) to provide the title compound as a sticky solid (87 mg, 77%): 1H NMR (400 MHz, CDCl3) δ 8.34 (d, J=8.1 Hz, 1H), 8.28 (d, J=5.4 Hz, 1H), 6.95 (d, J=5.4 Hz, 1H), 5.74 (s, 2H), 4.90 (dq, J=9.1, 6.4 Hz, 1H), 4.58 (ddt, J=9.4, 5.9, 4.6 Hz, 2H), 4.50-4.39 (m, 1H), 3.91 (s, 3H), 3.45 (dd, J=8.4, 6.6 Hz, 1H), 3.26 (dd, J=8.4, 6.4 Hz, 1H), 3.14-3.02 (m, 1H), 2.36 (dt, J=12.9, 6.7 Hz, 1H), 2.07 (s, 3H), 2.06-1.98 (m, 1H), 1.84 (dp, J=13.4, 6.7 Hz, 1H), 1.78-1.60 (m, 4H), 1.57 (s, 1H), 1.42 (d, J=6.4 Hz, 3H), 1.39-1.29 (m, 1H), 1.10 (dd, J=14.3, 5.7 Hz, 1H), 0.92 (d, J=6.8 Hz, 6H); 13C NMR (101 MHz, CDCl3) δ 170.35, 167.84, 160.52, 157.81, 143.31, 141.51, 140.02, 107.14, 87.11, 81.42, 81.36, 79.73, 77.78, 72.81, 53.74, 49.43, 37.34, 37.30, 31.13, 29.17, 28.98, 26.73, 26.26, 18.44, 17.02, 16.98, 16.74, 15.69; HRMS-ESI (m/z) ([M+Na]+) calcd for C25H37FN2O8Na, 535.2426, found 535.2423.
