Potassium Carbonate → (5S)-3-bromo-7-(3-pyridinyl)spiro[chromeno[2,3-b]pyridine-5,4'-[1,3]oxazol]-2'-amine

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Reaction Steps

A vial was charged with (S)-3-bromo-7-iodo-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine (906 mg, 1.978 mmol), pyridin-3-ylboronic acid (267 mg, 2.176 mmol), potassium carbonate (1367 mg, 9.89 mmol), and tetrakis(triphenylphosphine)palladium(0) (114 mg, 0.099 mmol). The vial was flushed with argon and dioxane (9.89 mL) and water (5.1 mL) were added in sequence. The vial was sealed and placed in an 80° C. oil bath for 4 h. The mixture was cooled to rt, diluted with EtOAc (45 mL), and brine (45 mL). The layers were separated, and the aq. layer was extracted with EtOAc (2×35 mL). The combined organic extracts were dried over sodium sulfate, filtered, and concentrated. The residue was purified by chromatography on a 40-g Redi-Sep column, eluting with 0-60% of a 90:10:1 mix of CH2Cl2/MeOH/NH4OH in CH2Cl2 to give (S)-3-bromo-7-(pyridin-3-yl)-5′H-spiro[chromeno[2,3-b]pyridine-5,4′-oxazol]-2′-amine as an off-white solid.

Provenance & Evidence