Imidazole → 6-(2-tert-butyidimethylsilyloxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran

HRID 1420762Notes

Reaction equation

[OH:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[S:8][C:9]1[CH:21]=[CH:20][C:12]2[O:13][C:14]([CH3:19])([CH3:18])[C:15]([CH3:17])=[CH:16][C:11]=2[CH:10]=1.N1C=CN=C1.[Si:27](Cl)([C:30]([CH3:33])([CH3:32])[CH3:31])([CH3:29])[CH3:28].O>CN(C)C=O>[Si:27]([O:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[S:8][C:9]1[CH:21]=[CH:20][C:12]2[O:13][C:14]([CH3:18])([CH3:19])[C:15]([CH3:17])=[CH:16][C:11]=2[CH:10]=1)([C:30]([CH3:33])([CH3:32])[CH3:31])([CH3:29])[CH3:28]

Participants

Conditions

Temperature: 40 °C

Procedure

6-(2-hydroxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran (1.1 g) (see Preparation 10) was dissolved in dry dimethylformamide (2 ml) and imidazole (0.55 g) and tert-butyidimethylsilyl chloride (0.61 g) were added. The flask was fitted with a calcium chloride drying tube and the mixture stirred at 40° C for 90 minutes. Water was added and the mixture was extracted with diethyl ether. The organic extract was washed with aqueous sodium hydrogen carbonate solution (×2), dried (anhydrous sodium sulphate), the solvent removed under reduced pressure and the crude product was chromatographed on silica using 4:1 hexane:dichloromethane as the eluent to yield 6-(2-tert-butyldimethylsilyloxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran (1.43 g) as an oil.

Workup

customThe flask was fitted with a calcium chloride drying tube
extractionthe mixture was extracted with diethyl ether
extractionThe organic extract
washwas washed with aqueous sodium hydrogen carbonate solution (×2)
dry with materialdried (anhydrous sodium sulphate)
customthe solvent removed under reduced pressure
customthe crude product was chromatographed on silica using 4:1 hexane

Sources & evidence

ORD record: ord-c6cf635cea654da794d69a5f7a88b482
Source dataset: uspto-grants-2000_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06071938

Reaction notes

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