反应详情

To a cooled suspension of lithium diisopropylamide {(1.45 mM tetrahydrofuran and n-hexane solution), 3.7 ml} and methyl 2-methylpropionate (0.6 g), a dried hexamethylphosphoric triamide (0.5 ml) was added at -65 to -57° C. Subsequently, 4-tert-butyl-2-(5-chloromethylbenzofuran-2-yl)thiazole was added to the mixture in small portions. After being stirred for 30 minutes at the same temperature, additive hexamethylphosphoric triamide (1.5 ml) was added to the mixture. The reaction mixture was gradually elevated to -10° C. for 1 hour. The resulting mixture was poured into ice-water and extracted with diethyl ether. The organic layer was washed with brine, dried over magnesium sulfate and concentrated under reduced pressure to give a syrup. The syrup was subjected to column chromatography on silica gel and eluted with a mixture of n-hexane and ethyl acetate (20:1). The fractions containing object compound were combined and concentrated under reduced pressure to give 4-tert-butyl-2-[5-(2-methyl-2-methoxycarbonylpropyl)benzofuran-2-yl]thiazole (0.43 g).

1. additionwas added to the mixture
2. extractionextracted with diethyl ether
3. washThe organic layer was washed with brine
4. dry with materialdried over magnesium sulfate
5. concentrationconcentrated under reduced pressure
6. customto give a syrup
7. washeluted with a mixture of n-hexane and ethyl acetate (20:1)
8. additionThe fractions containing object compound
9. concentrationconcentrated under reduced pressure