Methanol → 14-Tert-butoxycarbonylamino-18-(6-methoxy-isoquinolin-1-yloxy)-2,15-dioxo-10-oxa-3,16-diaza-tricyclo[14.3.0.04,6]nonadec-7-ene-4-carboxylic acid

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Reaction Steps

To a solution of 14-tert-butoxycarbonylamino-18-(6-methoxy-isoquinolin-1-yloxy)-2,15-dioxo-10-oxa-3,16-diaza-tricyclo[14.3.0.04,6]nonadec-7-ene-4-carboxylic acid ethyl ester (the product of step 26G, 667 mg, 1.02 mmol) in 25.7 ml of THF was added 2.9 ml of water, 11.4 ml of methanol, and powdered lithium hydroxide (489 mg, 20.4 mmol). The reaction mixture was stirred at rt for 6 h, and then concentrated in vacuo. The residue was partitioned between ethyl acetate and 20.4 ml of 1 N aq. HCl. To the resulting solution was added pH 4 buffer (biphthalate). The organic phase was washed with water, sat. aq. NaCl, dried (MgSO4), and concentrated in vacuo to give the crude product. Flash chromatography (silica gel, 0–10% methanol/chloroform) gave 446 mg (˜70%) of 14-tert-butoxycarbonylamino-18-(6-methoxy-isoquinolin-1-yloxy)-2,15-dioxo-10-oxa-3,16-diaza-tricyclo[14.3.0.04,6]nonadec-7-ene-4-carboxylic acid as a slightly pink collapsed foam: 1H NMR (500 MHz, METHANOL-D4) δ 0.99–1.16 (m, 1H), 1.22 (s, 9H), 1.50–2.04 (m, 6H), 2.40–2.73 (m, 3H), 3.41–3.50 (m, 1H), 3.51–3.62 (m, 1H), 3.73–3.86 (m, 1H), 3.90 (s, 3H), 4.03 (d, J=10.52 Hz, 1H), 4.21 (d, J=8.31 Hz, 1H), 4.42–4.72 (m, 3H), 5.65 (s, 2H), 5.82 (s, 1H), 7.06 (d, J=9.05 Hz, 1H), 7.15 (s, 1H), 7.22 (d, J=5.87 Hz, 1H), 7.87 (m, J=9.29 Hz, 2H), 8.14 (d, J=8.56 Hz, 1H). LC-MS (Method B, retention time: 1.46 min), MS m/z 625 (M++1).

Provenance & Evidence