反应详情

温度

60 °C

A suspension of (±)-methyl 6fluoro-3,4-dihydro-8-iodo-2H-1-benzopyran-2-carboxylate (0.026 mol), (trifluoromethyl)trimethylsilane (0.081 mol), cuprous iodide (0.1 mol) and kalium fluoride (0.081 mol) in a mixture of DMF (50 ml) and 1-methyl-2-pyrrolidinone (50 ml) was stirred for 3 h at 60° C. The cooled reaction mixture was poured out into a solution of iron (III) chloride (200 g) and hydrochloric acid (50 ml) in water (300 ml). This mixture was extracted three times with diethyl ether (150 ml). The combined organic layers were washed with a 5% aqueous Na2S2O3 solution (decolorization), dried (MgSO4), filtered and the solvent was evaporated. The residue was purified by flash column chromatography over silica gel (eluent: CH2Cl2). The pure fractions were collected and the solvent was evaporated, yielding 5.7 g (78.8%). This fraction was recrystallized from DIPE. The precipitate was filtered off and dried, yielding 1.2 g(16.6%) (±)-methyl 6-fluoro-3,4-dihydro-8-(trifluoromethyl)-2H-1-benzopyran-2-carboxylate; mp. 71.8° C. (interm 4-b).

1. customThe cooled reaction mixture
2. extractionThis mixture was extracted three times with diethyl ether (150 ml)
3. washThe combined organic layers were washed with a 5% aqueous Na2S2O3 solution (decolorization)
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. customthe solvent was evaporated
7. customThe residue was purified by flash column chromatography over silica gel (eluent: CH2Cl2)
8. customThe pure fractions were collected
9. customthe solvent was evaporated
10. customyielding 5.7 g (78.8%)
11. customThis fraction was recrystallized from DIPE
12. filtrationThe precipitate was filtered off
13. customdried