反应详情

To a solution of methyl 3-hydroxy-4,5-dimethylthiophene-2-carboxylate (Preparation 1) (29.7 g, 160 mmol) in anhydrous acetone (500 ml) was added anhydrous potassium carbonate (24.5 g, 178 mmol) and the mixture stirred for 1 hour at room temperature. Dimethyl sulphate (22.4 g, 178 mmol) was added and the mixture stirred under reflux for 2.5 hours. The solvent was evaporated under reduced pressure and the residue partitioned between water and ethyl acetate. The organic phase was washed with brine, dried with sodium sulphate and evaporated to give crude product which was used in the following preparation.

1. stirringthe mixture stirred
2. temperatureunder reflux for 2.5 hours
3. customThe solvent was evaporated under reduced pressure
4. customthe residue partitioned between water and ethyl acetate
5. washThe organic phase was washed with brine
6. dry with materialdried with sodium sulphate
7. customevaporated
8. customto give crude product which
9. customwas used in the following preparation