反应详情

温度

0 °C

1,1-Dimethylethyl 4-[5-(hydroxymethyl)-1,2,4-oxadiazol-3-yl]piperazine-1-carboxylate (7.4 g, 26 mmol) was taken into dichloromethane (100 mL) followed by addition of pyridine (5.3 mL, 65 mmol) and the solution was cooled to 0° C. Thionyl chloride (2.3 mL, 31.2 mmol) was added by syringe and the mixture was allowed to warm to room temperature and stirred an additional 12 hours. The mixture was then concentrated in vacuo and the residue partitioned with ethyl acetate and water. The aqueous phase was extracted twice with ethyl acetate and the combined organic layers were washed once with 0.1M aqueous hydrochloric acid then saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate. Filtration, concentration and purification of the residue by silica gel flash chromatography using 3:1 hexanes:ethyl acetate provided 1,1-dimethylethyl 4-[5-(chloromethyl)-1,2,4-oxadiazol-3-yl]piperazine-1-carboxylate (4.82 g, 61% yield) as a slightly yellow crystalline solid. 1H-NMR (400 MHz, CDCl3): 4.53 (s, 2H), 3.51 (tr, 4H), 3.43 (tr, 4H), 1.48 (s, 9H).

1. temperatureto warm to room temperature
2. concentrationThe mixture was then concentrated in vacuo
3. customthe residue partitioned with ethyl acetate and water
4. extractionThe aqueous phase was extracted twice with ethyl acetate
5. washthe combined organic layers were washed once with 0.1M aqueous hydrochloric acid
6. dry with materialsaturated aqueous sodium chloride and dried over anhydrous magnesium sulfate
7. filtrationFiltration, concentration and purification of the residue by silica gel flash chromatography