反应详情

A stirred solution of 4,5-dimethylcatechol (7.0 g.) in dry acetone (45 ml.) was heated under reflux, then potassium carbonate (5 g.) was added followed by the dropwise addition of ethyl dibromopropionate (3.5 g.). The addition procedure was repeated a further three times over 11/4 hours then the reaction was stirred under reflux for a further 33/4 hours. After cooling, the mixture was filtered, the solids washed well with acetone then the combined filtrate concentrated in vacuo. Water (35 ml.) was added, the resulting solid collected, washed with petrol then taken up in ether. The ethereal solution was washed with water, dried (Na2SO4) and evaporated in vacuo to give ethyl 6,7-dimethyl-1,4-benzodioxan-2-carboxylate (10.17 g.), m.p. 70°-71° C.

1. temperatureunder reflux
2. additionThe addition procedure
3. custom4 hours
4. temperatureunder reflux for a further 33/4 hours
5. temperatureAfter cooling
6. filtrationthe mixture was filtered
7. washthe solids washed well with acetone
8. concentrationthe combined filtrate concentrated in vacuo
9. additionWater (35 ml.) was added
10. customthe resulting solid collected
11. washwashed with petrol
12. washThe ethereal solution was washed with water
13. dry with materialdried (Na2SO4)
14. customevaporated in vacuo