反应详情

Dry HCl gas is bubbled through a solution of 5-hydroxy-3-methylbenzo(b)thiophene-2-carboxylic acid (1.0 g, 4.81 mmol) in methanol (150 ml) for 1 hour at room temperature. The brown solution is refluxed for 2 hours and concentrated. Extraction with ether, washing with water, aqueous sodium bicarbonate, water and bring, drying (MgSO4) and concentration affords the crude product which is subjected to flash chromatography over silica gel. Elution with 33% ethyl acetate in hexane affords methyl 5-hydroxy-3-methylbenzo(b)thiophene-2-carboxylate.

1. temperatureThe brown solution is refluxed for 2 hours
2. concentrationconcentrated
3. extractionExtraction with ether
4. washwashing with water, aqueous sodium bicarbonate, water
5. customdrying
6. concentration(MgSO4) and concentration
7. customaffords the crude product which
8. washElution with 33% ethyl acetate in hexane