Imidazole → 6-(4-tert-butyldimethylsilyloxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran

HRID 1416183Notes

Reaction equation

HRID 1416183 reaction equation
[OH:1][C:2]1[CH:7]=[CH:6][C:5]([S:8][C:9]2[CH:21]=[CH:20][C:12]3[O:13][C:14]([CH3:19])([CH3:18])[C:15]([CH3:17])=[CH:16][C:11]=3[CH:10]=2)=[CH:4][CH:3]=1.N1C=CN=C1.[Si:27](Cl)([C:30]([CH3:33])([CH3:32])[CH3:31])([CH3:29])[CH3:28]>CN(C)C=O>[Si:27]([O:1][C:2]1[CH:3]=[CH:4][C:5]([S:8][C:9]2[CH:21]=[CH:20][C:12]3[O:13][C:14]([CH3:18])([CH3:19])[C:15]([CH3:17])=[CH:16][C:11]=3[CH:10]=2)=[CH:6][CH:7]=1)([C:30]([CH3:33])([CH3:32])[CH3:31])([CH3:29])[CH3:28]

Participants

5

Reactant 3

HCID 795ImidazoleHCID 28928tert-Butyldimethylsilyl chlorideHCID 187828866-(4-hydroxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran

Product 1

HCID 538369336-(4-tert-butyldimethylsilyloxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyranYield 83.5%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
40 °C

Procedure

6-(4-Hydroxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran (5.799 g) (see Preparation 8) was dissolved in dry dimethylformamide (12 ml) and imidazole (2.768 g) and tert-butyidimethylsilyl chloride (2.923 g) were added. The flask was fitted with a calcium chloride drying tube and the mixture was stirred at 40° C. for 18 hours. The solvent was then removed under reduced pressure and the residue was partitioned between aqueous sodium bicarbonate solution and dichloromethane. The organic layer was dried (anhydrous sodium sulphate), the solvent removed under reduced pressure and the crude product chromatographed on silica using 1:1 hexane: dichloromethane as the eluent to yield 6-(4-tert-butyldimethylsilyloxyphenyl)thio-2,2,3-trimethyl-2H-benzo[b]pyran (6.681 g) as an oil. LRMS m/z=413 (m+1)+.

Workup

  1. customThe flask was fitted with a calcium chloride drying tube
  2. customThe solvent was then removed under reduced pressure
  3. customthe residue was partitioned between aqueous sodium bicarbonate solution and dichloromethane
  4. dry with materialThe organic layer was dried (anhydrous sodium sulphate)
  5. customthe solvent removed under reduced pressure
  6. customthe crude product chromatographed on silica using 1:1 hexane

Sources & evidence

ORD record
ord-06017e3e4b824eeda0c950559198386d
Source dataset
uspto-grants-1999_06
Patent number
US05912244

Reaction notes

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