Diisopropylethylamine → 5-Bromo-thiophene-2-sulfonic acid 6-chloro-2-oxo-2H-1-benzopyran-4-yl ester

Participants

Reaction Conditions

Reaction Steps

6-Chloro-4-hydroxycoumarin (0.5 mmol, 0.099 g) is suspended in 5 mL of DCM, and enough DIEA is added to bring the pH to 9 as measured by pH paper. The solution is cooled to 0° C., and 5-bromo-thiophene-2-sulfonyl chloride (0.5 mmol, 0.13 g) is added. The solution is warmed to ambient temperature and is stirred 2 hrs. The solvent is removed under reduced pressure and the residue is triturated with Et2O. The resulting solid is filtered, is washed with Et2O, and is dried to afford the title compound (45 mg, 21%). 1H NMR (CDCl3, 300 MHz) δ 7.65 (1H, d, J=4.25 Hz), 7.56 (2H, m), 7.29 (1H, d, J=8.75 Hz), 7.19 (1H, d, J=4.25 Hz), 6.48 (1H, s), MS (ESI, Pos.) calcd for C13H6BrClO5S2 m/z [M+H]=420.9, found 420.9.

Provenance & Evidence