Reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5]2[C:6](=O)[O:7][C:8](=O)[C:9]3[C:10]=2[C:11]=1[CH:12]=[CH:13][CH:14]=3.[BH4-].[Na+].FC(F)(F)C(O)=O.C([SiH](CC)CC)C>C(O)C>[Br:1][C:2]1[CH:3]=[CH:4][C:5]2[CH2:6][O:7][CH2:8][C:9]3[C:10]=2[C:11]=1[CH:12]=[CH:13][CH:14]=3Participants
6
Procedure
To 6-bromo-1H,3H-naphtho[1,8-cd]pyran-1,3-dione (1.5 g, 5.4 mmol) in ethanol (10 mL) was added sodium borohydride (0.41 g, 10.8 mmol) and the mixture stirred at room temperature for 1 h. The reaction was quenched with 3M hydrochloric acid and extracted into dichloromethane. The combined organic extracts were dried (Na2SO4) and concentrated in vacuo. The residue was dissolved in dichloromethane and trifluoroacetic acid (1.05 mL, 13.53 mmol) and triethylsilane (4.3 mL, 27 mmol) added. After stirring for 5 min at room temperature, the solvent was removed in vacuo and the residue purified by column chromatography on silica gel, eluting with dichloromethane, to yield 6-bromo-1H,3H-naphtho[1,8-cd]pyran as a white solid.
Workup
- customThe reaction was quenched with 3M hydrochloric acid
- extractionextracted into dichloromethane
- dry with materialThe combined organic extracts were dried (Na2SO4)
- concentrationconcentrated in vacuo
- dissolutionThe residue was dissolved in dichloromethane
- stirringAfter stirring for 5 min at room temperature
- customthe solvent was removed in vacuo
- customthe residue purified by column chromatography on silica gel
- washeluting with dichloromethane
Sources & evidence
- ORD record
- ord-93f7594914514440b42af07036f86d83
- Source dataset
- uspto-grants-2008_02
- Patent number
- US07335660B2
Linked notes
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