Methanol → 4H-1-Benzopyran-2-carboxylic acid, 4-oxo-, methyl ester

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Reaction Steps

Combine chromone-2-carboxylic acid (2.0 g, 10.5 mmol) and methanol (25 mL). Add sulfuric acid (2.5 mL) and heat to reflux. After 2 hours pour the reaction mixture into ice water and filter. Rinse the filter cake with water and a cold dilute aqueous solution of sodium bicarbonate. Chromatograph on silica gel eluting with tetrahydrofuran to give a residue. Recrystallize the residue from methanol to give the title compound as a solid: mp; 120°-122° C.

Provenance & Evidence