Cesium carbonate → trans-2-(6-Chloro-2-oxo-2H-1-benzopyran-4-yloxymethyl)-cyclopropanecarboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

6-chloro-4-hydroxycoumarin (5.09 mmol, 1.0 g) is dissolved in 80 mL of DMF, and Cs2CO3 (7.63 mmol, 2.49 g), and trans-2-methanesulfonyloxymethyl-cyclopropanecarboxylic acid methyl ester (6.14 mmol, 1.28 g) are added. The reaction is heated to 100° C. for 5 hrs, a further 0.2 eq of the mesylate is added, and heating is continued for an additional 2 hrs. After cooling to ambient temperature, the DMF is removed in vacuo. The residue is dissolved in EtOAc and is washed with H2O. The organic layer is dried over MgSO4, is filtered, and the EtOAc is removed under reduced pressure to afford a yellow solid which is chromatographed on SiO2 (35 g) using DCM as the eluent to afford the title compound as a white solid (0.98 g, 62%). 1H NMR (DMSO-d6, 300 MHz) δ 7.75 (2H, m), 7.45 (1H, d), 5.97 (1H, s), 4.22 (2H, m), 3.65 (3H, s), 1.90 (2H, m), 1.19 (2H, m); MS (ESI, Pos.) calcd for C15H13ClO5 m/z [M+H]=309.0, found 309.0.

Provenance & Evidence