反应详情

温度

-70 °C

2-Trimethylsilyl-1,3-dithiane (2.1 ml, 11.01 mmol) is dissolved in absolute THF (56 ml) and cooled to −70° C. with stirring. A solution of n-butyllithium in n-hexane (6.9 ml, 11.1 mmol of a 1.6 molar solution) is then slowly added dropwise under a nitrogen atmosphere by means of a glass syringe and the mixture is stirred at −45° C. for a further 30 min. After cooling to −70° C. again, a solution of 4-cyano-4-(2-isopropyl-7-methoxybenzoxazol-4-yl)cyclohexanone (1.5 g, 4.80 mmol, compound 3) in absolute THE (33 ml) is slowly added dropwise. The mixture is stirred at −70° C. for 1 h and then slowly warmed to RT (about 2 h). For working-up, the reaction solution is diluted with ethyl acetate (80 ml) and extracted (2 times) with 0.1 N hydrochloric acid (80 ml). The organic phase is dried using magnesium sulfate, filtered off and concentrated in vacuo. Column chromatography affords the title compound (1.34 9) as a colorless solid. TLC, silica gel (glass plates), petroleum ether/ethyl acetate (85:15), Rf=0.6.

1. stirringthe mixture is stirred at −45° C. for a further 30 min
2. temperatureAfter cooling to −70° C. again
3. stirringThe mixture is stirred at −70° C. for 1 h
4. temperatureslowly warmed to RT (about 2 h)
5. extractionextracted (2 times) with 0.1 N hydrochloric acid (80 ml)
6. customThe organic phase is dried
7. filtrationfiltered off
8. concentrationconcentrated in vacuo