Reaction Steps
A mixture of ethyl (2S)-2-(tert-butoxy)-2-{16-fluoro-4,23-dimethyl-11,22-dioxa-1,5,7,8-tetraazapentacyclo[21.2.2.16,9.02,7.013,18]octacosa-2,4,6(28),8,13(18),14,16-heptaen-3-yl}acetate (32 mg, 0.055 mmol) and NaOH (2.196 mg, 0.055 mmol) in EtOH (2 mL) was refluxed for 2 h. It was then cooled to rt and purified by preparative HPLC to isolate (2S)-2-(tert-butoxy)-2-{16-fluoro-4,23-dimethyl-11,22-dioxa-1,5,7,8tetraazapentacyclo[21.2.2.16,9.02,7.013,18]octacosa-2,4,6(28),8,13(18),14,16-heptaen-3-yl}acetic acid (13.9 mg, 0.025 mmol, 44.7% yield) as a white solid. 1H NMR (500 MHz, DMSO-d6) δ 7.49-7.41 (m, 1H), 7.11-7.00 (m, 2H), 6.47 (s, 1H), 5.91 (s, 1H), 4.92 (d, J=11.7 Hz, 1H), 4.75 (d, J=12.1 Hz, 1H), 4.71-4.55 (m, 3H), 3.84 (t, J=10.6 Hz, 1H), 3.50 (m, 2H), 3.16-3.01 (m, 3H), 2.59 (d, J=11.7 Hz, 1H), 2.53 (s, 3H), 1.99-1.79 (m, 4H), 1.77-1.54 (m, 2H), 1.24 (s, 3H), 1.19 (s, 9H). LCMS (M+1)=555.2.
