Reaction Steps
To a solution of ethyl (2S)-2-(tert-butoxy)-2-[(20S)-15-fluoro-4,20,26-trimethyl-11,19,25-trioxa-1,5,7,8-tetraazapentacyclo[24.2.2.16,9.02,7.013,18]hentriaconta-2,4,6(31),8,13,15,17-heptaen-3-yl]acetate (36.5 mg, 0.057 mmol) in Methanol (3 mL) was added sodium hydroxide/1N (0.285 mL, 0.285 mmol) and the resulting solution was refluxed. After 3 h, The mixture was cooled and concentrated. The residue was purified by prep HPLC to afford (2S)-2-(tert-butoxy)-2-[(20S)-15-fluoro-4,20,26-trimethyl-11,19,25-trioxa-1,5,7,8-tetraazapentacyclo[24.2.2.16,9.02,7.013,18]hentriaconta-2,4,6(31),8,13,15,17-heptaen-3-yl]acetic acid (4.2 mg, 11.31% yield). 1H NMR (500 MHz, DMSO-d6) δ 7.96 (s, 1H), 7.13 (dd, J=9.0, 2.8 Hz, 1H), 7.06-6.89 (m, 2H), 6.49 (s, 1H), 5.57 (s, 1H), 4.87 (d, J=12.5 Hz, 1H), 4.69-4.45 (m, 4H), 4.32 (t, J=11.6 Hz, 1H), 3.70-3.19 (m, 5H), 2.80 (br. s., 1H), 2.49-2.44 (m, 3H), 1.88 (d, J=14.3 Hz, 2H), 1.74-1.46 (m, 8H), 1.22-1.05 (m, 15H).
