反应详情

To a solution of ethyl 5-phenyl-1,3-oxazole-4-carboxylate (Example 29, 0.921 mmol, 1 eq.) in THF (7 mL) at −78° C. was added a solution of lithium bis(trimethylsilyl)amide in THF (1M, 1.11 mmol, 1.2 eq.) dropwise by syringe. The resulting solution was stirred at −78° C. for 1 hour at which time a solution of iodine (1.38 mmol, 1.5 eq. in 2 mL THF) was added dropwise by a syringe. The reaction mixture was allowed to warm to room temperature and stirred at this temperature for 1.5 hours. The resulting solution was poured onto 10% aqueous NaS2O3 (15 mL) and extracted with ethyl acetate. The organic extracts were washed with brine, dried over anhydrous sodium sulfate, concentrated in vacuo and purified by medium pressure column chromatography (Biotage 40S normal phase silica gel column, hexanes:EtOAc=9:1). The product was obtained as a pale yellow solid in 82% yield. MH+=344.0, Rf=0.31 (hexanes:EtOAc=6:1), retention time (LC-MS)=3.01 min.

1. additionwas added dropwise by a syringe
2. extractionextracted with ethyl acetate
3. washThe organic extracts were washed with brine
4. dry with materialdried over anhydrous sodium sulfate
5. concentrationconcentrated in vacuo
6. custompurified by medium pressure column chromatography (Biotage 40S normal phase silica gel column, hexanes:EtOAc=9:1)
7. customThe product was obtained as a pale yellow solid in 82% yield