Sodium Hydroxide → 8-[2-(Benzyloxymethyl)chromane-6-carboxamido]-4-oxo-4H-1-benzopyran-2-carboxylic acid

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Reaction Steps

A suspension of ethyl 8-[2-(benzyloxymethyl)chromane-6-carboxamido]-4-oxo-4H-1-benzopyran-2-carboxylate (0.240 g, 0.47 mmol) in a mixture of methanol (15 ml) and tetrahydrofuran (15 ml) was added with 0.510 ml of a 1M NaOH solution, stirring at room temperature for 1.30 h. After that the mixture was evaporated to dryness and the resulting residue was suspended in water adding 0.2M hydrochloric acid to slightly acid pH (pH=4-5). The solid was recovered by filtration, washed with methanol and dried on phosphorous pentoxyde under vacuum, thereby obtaining 0.221 g of the title compound as a white solid which decomposes above 283° C. (97% yield).

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