Trifluoroacetic acid → 4-(6,8-Dichloro-4-(ethoxycarbonyl)chroman-7-yloxy)benzoic acid

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Reaction Steps

To a solution of ethyl 7-(4-(tert-butoxycarbonyl)phenoxy)-6,8-dichlorochroman-4-carboxylate (1.85 g, 3.96 mmol) in 20 mL of DCM was added trifluoroacetic acid (10 mL). After stirring at ambient temperature for 1 hour, the mixture was concentrated to a sticky residue. The residue was dissolved in ethyl acetate and washed successively with saturated sodium bicarbonate and brine. The solution was dried over sodium sulfate and filtered. The filtrate was concentrated to give 4-(6,8-dichloro-4-(ethoxycarbonyl)chroman-7-yloxy)benzoic acid (1.85 g, 90.9% yield) as a powder. 1H NMR (400 MHz, CDCl3) δ 8.07 (d, J=8.8 Hz, 2H), 7.35 (s, 1H), 6.90 (d, J=8.8 Hz, 1H), 4.36-4.48 (m, 2H), 4.25 (q, J=7.1 Hz, 2H), 3.80 (t, J=4.7 Hz, 1H), 2.37-2.43 (m, 1H), 2.11-2.20 (m, 1H), 1.32 (t, J=7.2 Hz, 3H).

Provenance & Evidence