Pyridine → Phenyl 2-fluoro-4-(3-oxo-3,4-dihydropyrido[3,2-b]pyrazin-8-yloxy)phenylcarbamate

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Reaction Conditions

Reaction Steps

Dry pyridine (125 μL, 1.55 mmol) was added to a suspension of 8-(4-amino-3-fluorophenoxy)pyrido[2,3-b]pyrazin-3(4H)-one (307 mg, 1.13 mmol) in dry THF (20 mL) under Ar and the mixture was cooled to 0° C. Phenyl chloroformate (170 μL, 1.35 mmol) was added dropwise over 5 min and the light brown mixture was stirred at 0° C. for an additional 5 min whereafter the mixture was allowed to warm up to RT and was stirred for 150 min. The brownish mixture was concentrated to dryness and the resulting residue was diluted with EtOAc (60 mL) and H2O (30 mL). The organic layer was isolated and filtered (80 mg of impure product) and the filtrate was washed with aqueous saturated NaHCO3 and brine. The organic layer was evaporated to dryness, re-dissolved in CH2Cl2 and chromatographed on a Biotage 25+M column, eluting with 20%100% EtOAc in CH2Cl2 to give the title compound as a white solid. Yield: 280 mg (81%).

Provenance & Evidence