反应详情

温度

30 °C

Magnesium turnings (365 mg, 15.0 mmol, 1.5 equiv.) were suspended in 15 ml dry diethyl ether. A crystal of iodine and a few drops of 2-bromo-3-methylthiophene in 10 ml ether were added till the reaction started (3 min. with heating to 30° C.). The remaining solution of 2-bromo-3-methylthiophene (total 2.44 g, 10.0 mmol, 1.0 equiv.) was added dropwise to maintain the reaction at reflux. The reaction mixture was refluxed for 30 min. Toluene-4-sulfonic acid 3-methoxy-propyl ester (2.13 g, 12.0 mmol, 1.2 equiv.) dissolved in 5 ml diethyl ether was added dropwise and the yellow solution was refluxed again for 2 hours. The brown suspension was cooled, acidified with 1N HCl and extracted twice with ethyl acetate. The combined organics were washed with KHSO4/K2SO4 and brine, dried over Na2SO4, filtered, evaporated and chromatographed on a 50 g Silicagel cartridge with heptane and than MTBE-heptane 1:9 as solvent to give 2-(3-methoxy-propyl)-3-methyl-thiophene, 410 mg, m/e 170.0 (MH+) by GC/MS.

1. temperatureto maintain
2. customthe reaction
3. temperatureat reflux
4. temperatureThe reaction mixture was refluxed for 30 min
5. additionwas added dropwise
6. temperaturethe yellow solution was refluxed again for 2 hours
7. temperatureThe brown suspension was cooled
8. extractionextracted twice with ethyl acetate
9. washThe combined organics were washed with KHSO4/K2SO4 and brine
10. dry with materialdried over Na2SO4
11. filtrationfiltered
12. customevaporated
13. customchromatographed on a 50 g Silicagel cartridge with heptane and than MTBE-heptane 1:9 as solvent