反应详情

Acetyl chloride (5 mL) was added to a 0° C. solution of methanol (40 mL) and the solution was allowed to warm to room temperature. 5-Methyl-thiophene-2-carboxylic acid (Lancaster; 1.58 g, 11.1 mmol) was added and the solution was allowed to stir at room temperature over the weekend. The solvents were evaporated under reduced pressure and ethyl acetate was added. The solution was extracted with aqueous sodium hydrogen carbonate and the aqueous layer was back-extracted with ethyl acetate. The combined organic layers were dried (sodium sulfate) filtered and evaporated to give 5-methyl-thiophene-2-carboxylic acid methyl ester (1.40 g, 81%) as a yellow oil.

1. customThe solvents were evaporated under reduced pressure and ethyl acetate
2. additionwas added
3. extractionThe solution was extracted with aqueous sodium hydrogen carbonate
4. extractionthe aqueous layer was back-extracted with ethyl acetate
5. dry with materialThe combined organic layers were dried (sodium sulfate)
6. filtrationfiltered
7. customevaporated