反应详情

A solution of 3,4-dichlorophenyl acetic acid (4.6 g) in dry dichloromethane (100 ml) was treated with 1,1'-dicarbonyldiimidazole (3.6 g). The mixture was stirred at ambient temperature for 30 min. A solution of the product of stage (i) (1.13 g) in dry dichloromethane (20 ml) was added and the mixture was stirred at ambient temperature for 20 h. The mixture was washed with aqueous sodium carbonate solution (1M; 2×100 ml), dried (Na2SO4) and evaporated in vacuo. The residue was dissolved in tetrahydrofuran (50 ml) and a solution of lithium hydroxide (0.575 g) in water (40 ml) was added. The mixture was vigorously stirred at ambient temperature for 80 min. The organic solvent was removed in vacuo and the aqueous residue was extracted with dichloromethane (50 ml). The organic extract was dried (Na2SO4) and evaporated in vacuo to give a solid residue which was crystallised from methylacetate and hexane to give the title compound as a pale yellow solid (1.81 g) m.p. 155°-6°.

1. stirringthe mixture was stirred at ambient temperature for 20 h
2. washThe mixture was washed with aqueous sodium carbonate solution (1M; 2×100 ml)
3. dry with materialdried (Na2SO4)
4. customevaporated in vacuo
5. dissolutionThe residue was dissolved in tetrahydrofuran (50 ml)
6. additiona solution of lithium hydroxide (0.575 g) in water (40 ml) was added
7. stirringThe mixture was vigorously stirred at ambient temperature for 80 min
8. customThe organic solvent was removed in vacuo
9. extractionthe aqueous residue was extracted with dichloromethane (50 ml)
10. extractionThe organic extract
11. dry with materialwas dried (Na2SO4)
12. customevaporated in vacuo
13. customto give a solid residue which
14. customwas crystallised from methylacetate and hexane