Hydrochloric Acid → 2-t-Butyldimethylsilyl-3-formyl-6-methoxybenzofuran

HRID 1020470Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1020470
[Si:1]([CH:8]1[C:12](=[CH:13][O:14][Si](C(C)(C)C)(C)C)[C:11]2[CH:22]=[CH:23][C:24]([O:26][CH3:27])=[CH:25][C:10]=2[O:9]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].Cl>CO>[Si:1]([C:8]1[O:9][C:10]2[CH:25]=[C:24]([O:26][CH3:27])[CH:23]=[CH:22][C:11]=2[C:12]=1[CH:13]=[O:14])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:2])[CH3:3]

Komponenten

4

Edukt 2

HCID 313Hydrochloric AcidHCID 672878412-t-Butyldimethylsilyl-3-(t-butyldimethylsilyloxymethylene)-6-methoxy-benzofuran

Produkt 1

HCID 574219572-t-Butyldimethylsilyl-3-formyl-6-methoxybenzofuran

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 887MethanolLösungsmittel

Versuchsvorschrift

To a solution of 2-t-butyldimethylsilyl-3-(t-butyldimethylsilyloxymethylene)-6-methoxy-benzofuran (1.09 g, 2.69 mmol) in methanol (100 mL) was added concentrated hydrochloric acid (200 μL) and the reaction was stirred for 30 minutes (monitored by tlc), quenched with triethylamine (2 mL) and the solvent removed by distillation under vacuum. The residue was dissolved in dichloromethane (20 mL), washed with water (10 mL), dried over magnesium sulfate, concentrated under vacuum and co-distilled with toluene (20 mL); 1H NMR (300 MHz, CDCl3) δ 7.57 (d, 1H, J=8.57 Hz), 7.00 (d, 1H, J=2.17 Hz), 6.86 (dd, 1H, J=8.55, 2.22 Hz), 4.81 (s, 2H, CH2), 3.84 (s, 3H, OMe), 0.94 (s, 9H), 0.37 (s, 6H). The crude yellow paste (˜985 mg) was dissolved in dry dichloromethane (4 mL) and added to a stirred solution of Collin's reagent (chromium trioxide (1.01 g), pyridine (1.65 mL) in dry dichloromethane (30 mL)). The suspension was stirred for 10 minutes, filtered and the residue washed with diethyl ether (20 mL). The filtrate was concentrated onto silica (10 g) and purified by flash chromatography (silica gel, eluent=hexane/diethyl-ether/triethylamine (90:9:1) to afford the title compound as a light yellow oil which crystallized on standing (485 mg, 68%); 1H NMR (300 MHz, CDCl3) δ 10.25 (s, 1H, CHO), 8.06 (d, 1H, J=8.61 Hz), 7.03 (d, 1H, J=2.16 Hz), 6.95 (dd, 1H, J=8.60, 2.19 Hz), 3.84 (s, 3H, OMe), 0.97 (s, 9H), 0.46 (s, 6H); 13C NMR (75 MHz, CDCl3) δ 186.91 (CHO), 174.18, 159.19, 159.17, 132.82, 122.77, 117.34, 113.56, 95.36, 55.60, 27.04, 17.09, −5.24.

Aufarbeitung

  1. customquenched with triethylamine (2 mL)
  2. customthe solvent removed by distillation under vacuum
  3. dissolutionThe residue was dissolved in dichloromethane (20 mL)
  4. washwashed with water (10 mL)
  5. dry with materialdried over magnesium sulfate
  6. concentrationconcentrated under vacuum and co-distilled with toluene (20 mL)
  7. dissolutionThe crude yellow paste (˜985 mg) was dissolved in dry dichloromethane (4 mL)
  8. additionadded to a stirred solution of Collin's reagent (chromium trioxide (1.01 g), pyridine (1.65 mL) in dry dichloromethane (30 mL))
  9. stirringThe suspension was stirred for 10 minutes
  10. filtrationfiltered
  11. washthe residue washed with diethyl ether (20 mL)
  12. concentrationThe filtrate was concentrated onto silica (10 g)
  13. custompurified by flash chromatography (silica gel, eluent=hexane/diethyl-ether/triethylamine (90:9:1)

Quellen und Nachweise

ORD-Eintrag
ord-6609f6515347421cb5d3635002700d84
Quelldatensatz
uspto-grants-2014_05
Patentnummer
US08716335B2

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