反应详情

A solution of 2,2-dimethyl-3-(2-thienyl)propanoic acid (Va; 11.2 g., 0.06 mole), diphenylphosphorylazide (16.7 g., 0.06 mole) (Aldrich Chemical Company), and triethylamine (6.14 g., 0.06 mole) in tert.-butanol (100 ml.) was heated at reflux for 5 hr. The solution was poured into water (300 ml.) and the crude material extracted with Et2O. The combined extracts were washed with brine, dried over MgSO4 and finally evaporated to get 11.9 g. of crude intermediate. This oil was added to a mixture of ethylene glycol (50 ml.), H2O (20 drops) and KOH (10 g.). The mixture was heated at reflux for 5 hr., cooled to 25°, diluted with H2O (300 ml.) and acidified to pH 1 with conc. HCl. A wash with Et2O removed the acid insoluble material which was discarded. The aqueous solution was made basic with 50% NaOH and the product was extracted with Et2O. The ether extracts were washed with brine, dried over a MgSO4 and evaporated to give 6.9 g. (74%) of product. the NMR spectrum is consistent with the assigned structure.

1. temperatureat reflux for 5 hr
2. extractionthe crude material extracted with Et2O
3. washThe combined extracts were washed with brine
4. dry with materialdried over MgSO4
5. customfinally evaporated
6. customto get 11.9 g
7. temperatureThe mixture was heated
8. temperatureat reflux for 5 hr
9. temperature, cooled to 25°
10. washA wash with Et2O
11. customremoved the acid insoluble material which
12. extractionthe product was extracted with Et2O
13. washThe ether extracts were washed with brine
14. dry with materialdried over a MgSO4
15. customevaporated
16. customto give 6.9 g