反应详情

温度

-78 °C

Slowly add n-butyllithium (2.5 M in hexanes, 44.0 mL, 110 mmol) to a stirred solution of 2,4-dichloro-5-[1,3]dioxolan-2-yl-thiazole (19.33 g, 85.5 mmol) and anhydrous tetrahydrofuran (400 mL) at −78° C. under nitrogen. Stir for 1.5 h at −78° C. and then quench with water and pour the reaction into brine (300 mL). Extract with ethyl acetate (3×200 mL), dry over sodium sulfate, and filter off the sodium sulfate. Concentrate on a rotary evaporator and purify the crude product by flash chromatography on silica gel eluting with 25% ethyl acetate/hexanes to yield 15.27 g (93%) of 4-chloro-5-[1,3]dioxolan-2-yl-thiazole: mass spectrum (ion spray): m/z=192.0 (M+1); 1H NMR (CDCl3): δ=8.75 (s, 1H), 6.18 (s, 1H), 4.22-4.04 (m, 4H).

1. customat −78° C.
2. customquench with water
3. additionpour
4. customthe reaction into brine (300 mL)
5. extractionExtract with ethyl acetate (3×200 mL)
6. dry with materialdry over sodium sulfate
7. filtrationfilter off the sodium sulfate
8. concentrationConcentrate on a rotary evaporator
9. custompurify the crude product by flash chromatography on silica gel eluting with 25% ethyl acetate/hexanes