Reaction Steps
To a mixture of N-((3S,7R,8R,9S)-7-(cyclopentylmethyl)-8-(cyclopropylmethoxy)-9-methyl-2-oxooxonan-3-yl)-3-hydroxy-4-methoxypicolinamide (60 mg, 0.126 mmol) and K2CO3 (34.9 mg, 0.253 mmol) in acetone (1 mL) was added chloromethyl isobutyrate (34.5 mg, 0.253 mmol) and the reaction was heated to 60° C. After TLC analysis indicated full consumption of the picolinamide starting material, the mixture was concentrated under a stream of N2 and the residue purified by column chromatography on SiO2 (gradient, EtOAc/hexanes) to yield the title compound as a colorless semi-solid (60.4 mg, 83%): IR (thin film) 3381, 2942, 1745, 1678, 1506, 974 cm−1; 1H NMR (400 MHz, CDCl3) δ 8.38 (d, J=8.2 Hz, 1H), 8.27 (d, J=5.3 Hz, 1H), 6.93 (d, J=5.4 Hz, 1H), 5.81-5.61 (m, 2H), 4.89 (dd, J=9.2, 6.3 Hz, 1H), 4.57 (dt, J=11.0, 7.5 Hz, 1H), 3.89 (s, 3H), 3.50 (dd, J=9.6, 7.0 Hz, 1H), 3.36 (dd, J=9.6, 6.9 Hz, 1H), 3.01 (t, J=9.0 Hz, 1H), 2.54 (p, J=7.0 Hz, 1H), 2.36 (dd, J=13.1, 6.8 Hz, 1H), 1.92-1.43 (m, 15H), 1.42 (d, J=6.5 Hz, 2H), 1.35-1.19 (m, 2H), 1.14 (d, J=7.0 Hz, 3H), 1.17-0.92 (m, 5H), 0.62-0.48 (m, 2H), 0.29-0.17 (m, 2H); HRMS-ESI (m/z) ([M]+) calcd for C31H46N2O8, 574.3254; found, 574.3262.
