Perchloric Acid → ethyl 2-[4-(3,4-dihydro-2H-1-benzopyran-6-yl)-2,5-dimethyl thiophen-3-yl]-tert-butoxy-acetate

HRID 591023Notes

Reaction equation

HRID 591023 reaction equation
Cl(O)(=O)(=O)=O.[O:6]1[C:11]2[CH:12]=[CH:13][C:14]([C:16]3[C:17]([CH:23]([OH:29])[C:24]([O:26][CH2:27][CH3:28])=[O:25])=[C:18]([CH3:22])[S:19][C:20]=3[CH3:21])=[CH:15][C:10]=2[CH2:9][CH2:8][CH2:7]1>C(OC(C)(C)C)(=O)C>[O:6]1[C:11]2[CH:12]=[CH:13][C:14]([C:16]3[C:17]([CH:23]([O:29][C:10]([CH3:15])([CH3:11])[CH3:9])[C:24]([O:26][CH2:27][CH3:28])=[O:25])=[C:18]([CH3:22])[S:19][C:20]=3[CH3:21])=[CH:15][C:10]=2[CH2:9][CH2:8][CH2:7]1

Participants

4

Reactant 2

HCID 24247Perchloric AcidHCID 70855186ethyl 2-[4-(3,4-dihydro-2H-1-benzopyran-6-yl)-2,5-dimethyl thiophen-3-yl]-2-hydroxyacetate

Product 1

HCID 70855183ethyl 2-[4-(3,4-dihydro-2H-1-benzopyran-6-yl)-2,5-dimethyl thiophen-3-yl]-tert-butoxy-acetateYield 88%

Reagents, catalysts & solvents 1

HCID 10908tert-Butyl acetateSolvent

Procedure

Under a nitrogen atmosphere, perchloric acid (70%, 1.5 mL) was added at −10° C. to a solution of ethyl 2-[4-(3,4-dihydro-2H-1-benzopyran-6-yl)-2,5-dimethyl thiophen-3-yl]-2-hydroxyacetate (17e) (88 mg, 0.25 mmol) in tert-butyl acetate (10 mL). After 1 hour, the reaction was quenched with a saturated aqueous solution of sodium carbonate and extracted with dichloromethane (2×30 mL). The organic layer was washed with brine (20 mL), dried over sodium sulfate, filtered and evaporated under reduced pressure. The residue was purified by flash chromatography on silica gel (dichloromethane)) to afford the desired product (17f) as a white solid (43 mg, 0.11 mmol, 43%).

Workup

  1. customthe reaction was quenched with a saturated aqueous solution of sodium carbonate
  2. extractionextracted with dichloromethane (2×30 mL)
  3. washThe organic layer was washed with brine (20 mL)
  4. dry with materialdried over sodium sulfate
  5. filtrationfiltered
  6. customevaporated under reduced pressure
  7. customThe residue was purified by flash chromatography on silica gel (dichloromethane))

Sources & evidence

ORD record
ord-71d0b71abc144e5896b10b0ed18872c5
Source dataset
uspto-grants-2016_01
Patent number
US09238026B2

Reaction notes

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