Acetic Acid → [6-(6-methoxy-3,4-dihydro-2H-1-oxa-4,5,9-triaza-phenanthren-3-yl)-pyridin-3-yl]-carbamic acid tert-butyl ester

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Reaction Steps

Acetic acid (110 mg, 1.83 mmol, 1.7 eq) is added at room temperature to a stirred solution of {6-[2-(4-amino-6-methoxy-[1,5]naphthyridin-3-yloxy)-acetyl]-pyridin-3-yl}-carbamic acid tert-butyl ester (470 mg, 1.10 mmol 1.0 eq) in methanol (20 mL) and the resulting mixture is stirred at room temperature for 1 hour before the addition of sodium cyanoborohydride (370 mg, 5.89 mmol, 5.3 eq). After 4 hours stirring at room temperature, the reaction mixture is extracted with dichloromethane (3×10 mL) and a saturated sodium hydrogen carbonate aqueous solution (10 mL). The combined organic layers are dried over sodium sulfate, filtered and concentrated to give a residue that is purified by column chromatography (silica gel, eluent: dichloromethane:methanol, 200:1 to 50:1, v/v) to afford [6-(6-methoxy-3,4-dihydro-2H-1-oxa-4,5,9-triaza-phenanthren-3-yl)-pyridin-3-yl]-carbamic acid tert-butyl ester as a light yellow solid (222 mg, 49% yield).

Provenance & Evidence