反应详情

To a stirred mixture of 2,6-difluoro-3-isopropoxy-phenol (5.74 g, 0.031 mol) and ethyl-2-butynoate (6.85 g, 0.061 mol) in tetrahydrofuran (50 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (4.64 g, 0.030 mol) slowly. After addition was complete the mixture was stirred at reflux for 6 h. Upon completion of the reaction the tetrahydrofuran was removed in vacuo and the residue was diluted in diethyl ether and washed first with 1N aqueous hydrochloric acid, then 10% aqueous sodium hydroxide solution, a saturated sodium chloride solution and dried over magnesium sulfate. The mixture was filtered and evaporated which afforded (E)-3-(2,6-difluoro-3-isopropoxy-phenoxy)-but-2-enoic acid ethyl ester as a brown oil (6.85 g, 75%) and used without further purification.

1. additionAfter addition
2. temperatureat reflux for 6 h
3. customwas removed in vacuo
4. additionthe residue was diluted in diethyl ether
5. washwashed first with 1N aqueous hydrochloric acid
6. dry with material10% aqueous sodium hydroxide solution, a saturated sodium chloride solution and dried over magnesium sulfate
7. filtrationThe mixture was filtered
8. customevaporated which