反应详情

温度

40 °C

NCS (850 mg, 6.37 mmol) was added to a solution of 3,5-difluorobenzaldehyde oxime (1.00 g, 6.37 mmol) in DMF (60 ml), and the mixture was stirred at 40° C. for 1 h. Heating was then switched off, and ethyl 2-cyanoacrylate (1.20 g, 9.55 mmol) and NaHCO3 (561 mg, 6.68 mmol) were added. The mixture was stirred at RT for 2 h, and water (400 ml) was then added. The mixture was extracted with MTBE (3×50 ml), and the combined organic phases were washed with dilute sulfuric acid (0.5 M, ml), dried over Na2SO4 and concentrated. Chromatography of the residue on silica gel using the mobile phase heptane/EtOAc gave 810 mg of slightly contaminated ethyl 5-cyano-3-(3,5-difluorophenyl)-4,5-dihydro-1,2-oxazole-5-carboxylate, which was used without further purification.

1. temperatureHeating
2. stirringThe mixture was stirred at RT for 2 h
3. extractionThe mixture was extracted with MTBE (3×50 ml)
4. washthe combined organic phases were washed with dilute sulfuric acid (0.5 M, ml)
5. dry with materialdried over Na2SO4
6. concentrationconcentrated