Reaction Steps
A similar procedure (Schwartz, E. et al. Macromolecules 2011, 44, 4735-4741) to that previously described for the preparation of 347 was followed using 106 (0.8 g, 0.7 mmol), 4-methoxycinnamic acid (0.1 g, 0.8 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (0.16 g, 0.8 mmol), triethylamine (0.1 mL, 0.8 mmol) and dimethylaminopyridine (9 mg, 0.07 mmol) in dichloromethane (10 mL), at room temperature for 24 h. Purification by flash chromatography (hexane/ethyl acetate 1:5) afforded 361 as a white solid (0.4 g, 0.6 mmol, 85%). 1H NMR (300 MHz, CDCl3) δ 3.35-3.91 (6.6H, m, NCH2CH2NHCO, H-2, H-3, U/H-1, V/H-1, W/H-4), 3.83-3.85 (3H, m, OMe), 3.95 (0.4H, m, Y/H-4), 4.15 (0.1H, m, U/H-4), 4.33 (0.3H, m, V/H-4), 4.47-4.50 (0.6H, m, W/H-1, Y/H-1), 5.46 (0.6H, s, OH), 5.53 (0.3H, dd, m, V/H-6), 5.56 (0.4H, m, Y/H-6), 5.77 (0.4, s, OH), 6.20-6.40 (1.3H, m, COCH═CH, W/H-6, U/H-6), 6.70-7.65 (21H, m, Ar and COCH═CH), 8.40-8.62 (2H, m, αPyr).
