反应详情

Into a 1 L round bottom flask equipped with mechanical stirring and reflux condenser was charged methyl 2-(5-ethoxycarbonylamino-1,2,4-thiadiazol-3-yl)-bromoacetate (50.0 g, 0.154 mol, 1.0 eq.) followed by acetonitrile (500 mL). To the clear light yellow solution was charged pyridine N-oxide (37.0 g, 0.385 mol, 2.5 eq) and the reaction mixture was heated to reflux and maintained there for three hours until reaction completion was determined by proton NMR analysis. The solution was cooled and the acetonitrile was removed by rotary evaporation to give a thin yellow oil. The oil was dissolved in dichloromethane (500 mL) and the organic was washed once with brine (1×200 mL). The brine solution was extracted several times with dichloromethane (5×100 mL) and the organic layers were combined and dried with sodium sulfate, filtered and the solvent evaporated to give a clear slightly yellow oil which solidified upon standing at room temperature. The solid was dried under high vacuum to give 37.36 grams of the title compound. 1H NMR (CDCl3) δ 1.40 (t, 3H); 4.06 (s, 3H); 4.46 (q, 2H).

1. customInto a 1 L round bottom flask equipped
2. temperaturereflux condenser
3. temperaturethe reaction mixture was heated
4. temperatureto reflux
5. temperaturemaintained there for three hours until reaction completion
6. temperatureThe solution was cooled
7. customthe acetonitrile was removed by rotary evaporation
8. customto give a thin yellow oil
9. washthe organic was washed once with brine (1×200 mL)
10. extractionThe brine solution was extracted several times with dichloromethane (5×100 mL)
11. dry with materialdried with sodium sulfate
12. filtrationfiltered
13. customthe solvent evaporated
14. customto give a clear slightly yellow oil which
15. customupon standing at room temperature
16. customThe solid was dried under high vacuum