反应详情

温度

-78 °C

5-[2-(3,4-Dimethoxy-phenyl)-vinyl]-3-propyl-[1,2,4]oxadiazole (compound of Example 3, Method A, Step 1; 1.28 g, 4.66 mmol) was dissolved in dichloromethane (15 mL) and cooled to −78° C. A solution of boron tribromide (4.42 mL, 4.66 mmol) in dichloromethane (5 mL), which was cooled to 0° C., was added slowly over a period of 25 min. After 2 h, the reaction mixture was allowed to warm to room temperature (25° C.) and stirred for 2 h. At the end of the reaction, the mixture was quenched by dropwise addition of methanol (15 mL) at 0° C. and stirred for 20 min at room temperature. The solvent was evaporated and the residue obtained was redissolved in 10% methanol in chloroform at 0° C. and stirred with solid sodium carbonate to obtain pH ˜8. The solvent was evaporated and the crude product obtained was purified by column chromatography (silica gel, 0.5% methanol in chloroform) to afford the title compound.

1. additionwas added slowly over a period of 25 min
2. temperatureto warm to room temperature (25° C.)
3. customAt the end of the reaction
4. customthe mixture was quenched by dropwise addition of methanol (15 mL) at 0° C.
5. stirringstirred for 20 min at room temperature
6. customThe solvent was evaporated
7. customthe residue obtained
8. customto obtain pH ˜8
9. customThe solvent was evaporated
10. customthe crude product obtained
11. customwas purified by column chromatography (silica gel, 0.5% methanol in chloroform)