Sodium borohydride → 6-tert-butyl-2-[4-[5-(6,7-dihydro-4H-pyrazolo[5,1-c][1,4]oxazin-2-ylamino)-1-methyl-6-oxo-3-pyridyl]-3-(hydroxymethyl)-2-pyridyl]-8-fluoro-phthalazin-1-one

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Reaction Steps

A 50-mL single-neck round-bottomed flask equipped with a magnetic stirrer was charged with 131e (220 mg, 1.0 eq., 0.39 mmol), NaBH4 (73 mg, 5.0 eq., 1.90 mmol), and methanol (10 mL). The mixture was stirred at room temperature for 1 h and quenched with water (5 mL). It was then concentrated under reduced pressure and resulting residue was extracted with dichloromethane (3×10 mL). The combined organic layer was concentrated under reduced pressure and the residue was purified by reverse-phase prep-HPLC to afford 131 (105 mg, 47%). MS-ESI: [M+H]+ 571.8. 1H NMR (500 MHz, CDCl3) δ 8.66 (d, J=5.0 Hz, 1H), 8.35 (d, J=2.5 Hz, 1H), 8.03 (d, J=2.5 Hz, 1H), 7.59-7.53 (m, 4H), 7.48 (s, 1H), 5.73 (s, 1H), 4.81 (s, 2H), 4.51 (bs, 2H), 4.12-4.05 (m, overlap, 5H), 3.73 (s, 3H), 1.46 (s, 9H).

Provenance & Evidence