反应详情

40 g of Potassium t-butoxide was added to 150 ml of diethyl oxalate in small portions with stirring. After the initial exothermic reaction subsided, the reaction mixture was heated on a steam bath under nitrogen in order to dissolve solids. After cooling down to room temperature, 79 g of 4-biphenyl acetic acid methyl ester was added in one portion. The mixture was stirred at 60°-70° C. for 2 hours while low boiling material was removed under vaccum. On cooling to room temperature, the viscous residue was stirred with 200 ml of ether and 350 ml of water with cooling. The ether layer was separated and extracted once with 100 ml of water. The aqueous layers were combined, extracted once with ether, made acidic with concentrated HCl (cooling) and extracted with 2×300 ml of ether. Some solids did not dissolve in the ether layer and were filtered. The ether layer was then evaporated to dryness. and the semi solid residue was combined with the preceeding solids. A mixture of 160 ml of conc. HCl and 350 ml of acetic acid was added to the solids and heated under reflux for 21/2 hours. On cooling down to ca. 50° C. a solid preciptated, which was filtered and washed with 150 ml of water. The wet solid was stirred with 150 ml of acetonitrile for five minutes, then filtered and dried under high vaccum at room temperature for 3 hours. 42.2 g of the title compound m.p. 215°-218° C. were obtained.

1. customAfter the initial exothermic reaction
2. temperaturethe reaction mixture was heated on a steam bath under nitrogen in order
3. dissolutionto dissolve solids
4. stirringThe mixture was stirred at 60°-70° C. for 2 hours while low boiling material
5. customwas removed under vaccum
6. temperatureOn cooling to room temperature
7. stirringthe viscous residue was stirred with 200 ml of ether and 350 ml of water
8. temperaturewith cooling
9. customThe ether layer was separated
10. extractionextracted once with 100 ml of water
11. extractionextracted once with ether
12. extractionextracted with 2×300 ml of ether
13. dissolutionSome solids did not dissolve in the ether layer
14. filtrationwere filtered
15. customThe ether layer was then evaporated to dryness
16. additionA mixture of 160 ml of conc. HCl and 350 ml of acetic acid
17. additionwas added to the solids
18. temperatureheated
19. temperatureunder reflux for 21/2 hours
20. temperatureOn cooling down to ca. 50° C. a solid preciptated
21. filtrationwhich was filtered
22. washwashed with 150 ml of water
23. stirringThe wet solid was stirred with 150 ml of acetonitrile for five minutes
24. filtrationfiltered
25. customdried under high vaccum at room temperature for 3 hours