6-Bromo-2,2-dimethyl-2H-chromene → 2,2-Dimethyl-6-phenylsulfanyl-2H-chromene

HRID 1175036Notes

Reaction equation

Br[C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7]([CH3:13])([CH3:12])[CH:6]=[CH:5]2.C([Li])CCC.[CH:19]12S[CH:20]1[CH:21]1[S:25][CH:22]1[CH:23]=[CH:24]2>C1COCC1>[CH3:12][C:7]1([CH3:13])[CH:6]=[CH:5][C:4]2[C:9](=[CH:10][CH:11]=[C:2]([S:25][C:22]3[CH:23]=[CH:24][CH:19]=[CH:20][CH:21]=3)[CH:3]=2)[O:8]1

Participants

Conditions

Temperature: -78 °C

Procedure

6-Bromo-2,2-dimethyl-2H-chromene (10 mmoL) in THF (20 mL) was treated with n-butyl lithium (15 mmoL) dropwise at −78° C. The resulting solution was stirred at −78° C. for 30 min. Benzene disulfide (10 mmoL) in THF (10 mL) was then added dropwise into the reaction over about 15 min. The reaction mixture was kept at −78° C. and slowly warmed to room temperature over 2 hrs. The solvent was removed and the residue was partitioned between diethyl ether and water. The combined organic layer was washed with brine, filtered, dried over anhydrous Na2SO4 and concentrated to yield crude material, which was purified by silica gel chromatography to yield the title compound as a white solid.

Workup

customwas kept at −78° C.
temperatureslowly warmed to room temperature over 2 hrs
customThe solvent was removed
customthe residue was partitioned between diethyl ether and water
washThe combined organic layer was washed with brine
filtrationfiltered
dry with materialdried over anhydrous Na2SO4
concentrationconcentrated
customto yield crude material, which
customwas purified by silica gel chromatography

Sources & evidence

ORD record: ord-5e62cb6da0d34ff894f16e802d790e40
Source dataset: uspto-grants-2010_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07838553B2

Reaction notes

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