Carbon Dioxide → 2-Methyl-1-benzothiophene-7-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

The solution of 7-bromo-2-methylbenzo[b]thiophene (508) (0.908 g, 4.0 mmol) in tetrahydrofuran (16 mL) was cooled to −78° C. under nitrogen. n-butyllithium (2.40 mL, 6.0 mmol, 1.0M in Hexanes) was added dropwise. After the addition was complete, the reaction mixture was stirred at −78° C. for 1 h, then poured on to the mixture of dry ice in ethyl ether (30 mL). The reaction was stirred to reach room temperature for 5 hours, followed by washing with 1N HCl, brine and dried over sodium sulfate, filtered, and concentrated in vacuo. The obtained white solid was washed with hexanes to provide 2-methylbenzo[b]thiophene-7-carboxylic acid (509) (0.240 g, 31.2%). LC-MS ESI m/z: found 191.0 [M−H]−.

Provenance & Evidence