反应详情

2-Acetoxymethyl-2,3-dihydro-thieno[3,4-b][1,4]dioxine-5,7-dicarboxylic acid dimethyl ester (60 g, 0.18 mol) was dissolved in ethanol (680 mL). potassium hydroxide (36 g) was added to this solution after which water (500 mL) was added upon continuous cooling. After addition of the water the reaction mixture was stirred for another 30 minutes after which the solvents were removed by distillation. To the remaining part of the reaction mixture, we dropwise added a mixture of ice (50 g) and concentrated hydrochloric acid (25 mL), and stirred. The mixture was then filtered and the residue was washed with water. Subsequent drying resulted in quantitative formation of pure 2-hydroxymethyl-2,3-dihydro-thieno[3,4-b][1,4]dioxine-5,7-dicarboxylic acid as demonstrated by NMR and mass spectroscopy.

1. additionwas added upon continuous cooling
2. customwere removed by distillation
3. additionTo the remaining part of the reaction mixture, we dropwise added
4. additiona mixture of ice (50 g) and concentrated hydrochloric acid (25 mL)
5. stirringstirred
6. filtrationThe mixture was then filtered
7. washthe residue was washed with water
8. customSubsequent drying