Reaction Steps
A solution of (E)-(1S,14R,15R,18S,21S)-21-[3-(tert-butyl-dimethyl-silanyloxy)-benzyl]-18-isopropyl-14-methoxy-15-methyl-3-oxa-6,17,20,23,27-pentaaza-tricyclo[21.3.1.1*5,9*]octacosa-5(28),6,8,10-tetraene-2,16,19,22-tetraone (160 mg, 0.21 mmol) in tetrahydrofuran (10 mL) was stirred at 0° C. under nitrogen. A solution of tetra-N-butylammonium fluoride (1 M in tetrahydrofuran, 0.34 mL, 0.34 mmol) was added and the reaction mixture was stirred at 0° C. for 15 minutes and then at room temperature for 15 minutes. Silica gel was added and the solvent was evaporated. The residue was purified by silica gel chromatography using a gradient of ethyl acetate to ethyl acetate/acetone 9:1 to afford the title compound (88 mg, 65%) as a white solid. 1H NMR (300 MHz, CD3CN) δ0.97 (d, J=7.1 Hz, 3H), 0.99 (d, J=7.1 Hz, 3H), 1.32 (d, J=7.4 Hz, 3H), 1.60-2.20 (m, 9H), 2.55-2.89 (m, 4H), 3.28-3.34 (m, 1H), 3.46 (s, 3H), 3.62-3.69 (m, 1H), 4.19-4.41 (m, 3H), 5.19 (d, J=14.5 Hz, 1H), 5.35 (d, J=14.5 Hz, 1H), 5.58-5.65 (m, 1H), 5.83 (d, J=15.8 Hz, 1H), 6.30-6.39 (m, 1H), 6.51 (dd, J=7.9, 1.6 Hz, 1H), 6.67 (d, J=7.6 Hz, 1H), 6.75-6.81 (m, 1H), 7.01-7.07 (m, 3H), 7.22-7.28 (m, 2H), 8.02 (s, 1H), 8.39 (d, J=5.1 Hz, 1H).
