Water → HCID 131727976, compound

Participants

Reaction Steps

Trifluoromethanesulfonic anhydride (4.6 ml 27 mmol, 1.5 equiv) was dropwise added to a 0° C. solution of 3-hydroxy-benzo[b]thiophene-2,6-dicarboxylic acid 6-tert-butyl ester 2-methyl ester (5.56 g, 18 mmol) in DCM (50 ml) and Et3N (50 ml). The reaction mixture was warmed to RT and stirred for 30 min. After adding water and EtOAc the crude reaction mixture was washed with sat. NaHCO3 then dried over MgSO4. Filtration, evaporation, and purification by column chromatography yielded 4.56 g (57%) of 3-trifluoromethanesulfonyloxy-benzo[b]thiophene-2,6-dicarboxylic acid 6-tert-butyl ester 2-methy ester. 1H NMR (400 MHz, CHLOROFORM-D) δ ppm 1.64 (s, 9H) 4.01 (s, 3H) 7.87 (d, J=8.59 Hz, 1H) 8.12 (dd, J=8.59, 1.52 Hz, 1H) 8.50 (s, 1H). HRMS (ESI+, m/z) calcd for [M+NA]1+, 463.01035, found 463.01013.

Provenance & Evidence