반응 단계
Bromomethyl acetate (48 uL, 0.49 mmol) was added to a suspension of N-((3S,7S,8R,9S)-7-benzyl-8-isobutoxy-9-methyl-2-oxo-1,5-dioxonan-3-yl)-3-hydroxy-4-methoxypicolinamide (160 mg, 0.33 mmol), sodium iodide (NaI, 2.5 mg, 0.02 mmol) and sodium carbonate (Na2CO3; 56 mg, 0.53 mmol) in acetone (3 mL). The mixture was heated to 50° C. and stirred overnight. The suspension was diluted with acetone and filtered. The yellow solution was concentrated and purified by flash chromatography (50% EtOAc in hexanes) to furnish the product as a white foam (97 mg, 53%): IR (film) 3370, 3025, 2957, 2874, 1752, 1677 cm−1; 1H NMR (400 MHz, CDCl3) δ 8.39 (d, J=8.2 Hz, 1H), 8.27 (d, J=5.4 Hz, 1H), 7.34-7.23 (m, 2H), 7.20 (dd, J=7.2, 4.8 Hz, 3H), 6.95 (d, J=5.4 Hz, 1H), 5.80-5.64 (m, 2H), 5.13-4.92 (m, 2H), 4.02 (dd, J=11.7, 7.4 Hz, 1H), 3.90 (s, 3H), 3.54-3.28 (m, 5H), 3.14 (dd, J=11.7, 6.4 Hz, 2H), 2.40-2.23 (m, 1H), 2.06 (s, 3H), 2.01-1.82 (m, 2H), 1.50 (d, J=6.4 Hz, 3H), 0.93 (d, J=6.7 Hz, 6H); 13C NMR (101 MHz, CDCl3) δ 171.81, 170.31, 163.18, 160.20, 145.79, 143.93, 142.15, 140.02, 129.21 (2), 128.44 (2), 126.10, 109.69, 89.41, 84.58, 79.26, 75.74, 72.34, 72.16, 56.19, 51.81, 47.45, 35.09, 29.19, 20.88, 19.50 (2), 18.83; ESIMS m/z 560.36 ([M+H]+).
