反应详情

To 654 mg of (+)-7,8-dihydro-6,6-dimethyl-7-hydroxy-8-amino-6H-pyrano[2,3-f]benzo-2,1,3-oxadiazole dissolved in 10 mL of ethyl acetate were added 337 mg of triethylamine and dropwise added 696 mg of 5-bromo-3,3-dimethylvaleryl chloride at the room temperature over a 10-minute period, followed by stirring at the room temperature for one hour. The reaction mixture was added with 20 ml of saturated aqueous NaCl solution, and extracted twice with ethyl acetate (each 20 mL). After the extract was dried over anhydrous sodium sulfate and the solvent was distilled off under reduced pressure. The residue was dissolved in 66 g of dimethylformamide and was dropwise added with 2.7 g of 20% tetraethylammonium hydroxide solution over 20 minutes under ice-cooling. Under ice-cooling, the mixture was reacted for 30 min. and then, the solvent was distilled off under reduced pressure and was added with 20 mL of saturated aqueous NaCl solution and extracted thrice with methylchloride (each 20 mL). After the extract was dried over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure The residue was subjected to a silica gel column chromatography (ethyl acetate:n-hexane=1:1, Rf=0.5) to obtain 598 mg of the intended compound as colorless crystals.

1. extractionextracted twice with ethyl acetate (each 20 mL)
2. dry with materialAfter the extract was dried over anhydrous sodium sulfate
3. distillationthe solvent was distilled off under reduced pressure
4. dissolutionThe residue was dissolved in 66 g of dimethylformamide
5. additionwas dropwise added with 2.7 g of 20% tetraethylammonium hydroxide solution over 20 minutes under ice-
6. temperaturecooling
7. temperatureUnder ice-cooling
8. customthe mixture was reacted for 30 min.
9. distillationthe solvent was distilled off under reduced pressure
10. additionwas added with 20 mL of saturated aqueous NaCl solution
11. extractionextracted thrice with methylchloride (each 20 mL)
12. dry with materialAfter the extract was dried over anhydrous sodium sulfate
13. distillationthe solvent was distilled off under reduced pressure The residue