Ethanol → Bromo-PEG4-t-butyl ester

HRID 2083890Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 2083890
[C:1]([O:5][C:6](=[O:22])[CH2:7][CH2:8][O:9][CH2:10][CH2:11][O:12][CH2:13][CH2:14][O:15][CH2:16][CH2:17][O:18][CH2:19][CH2:20]O)([CH3:4])([CH3:3])[CH3:2].C(O)C.C(Br)(Br)(Br)[Br:27].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>ClCCl.C1(C)C=CC=CC=1>[C:1]([O:5][C:6](=[O:22])[CH2:7][CH2:8][O:9][CH2:10][CH2:11][O:12][CH2:13][CH2:14][O:15][CH2:16][CH2:17][O:18][CH2:19][CH2:20][Br:27])([CH3:4])([CH3:3])[CH3:2]

Komponenten

7

Edukt 4

HCID 702EthanolHCID 11205Carbon tetrabromideHCID 11776TriphenylphosphineHCID 11174684Hydroxy-PEG4-t-butyl ester

Produkt 1

HCID 12082266Bromo-PEG4-t-butyl esterAusbeute 47,5 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 1140TolueneLösungsmittelHCID 6344DichloromethaneLösungsmittel

Versuchsvorschrift

Alternatively, 1.61 g (5.03 mmol) of 9a was co-evaporated successively with 100% ethanol and toluene, then dried over anhydrous sodium sulfate and 4A molecular sieves in dichloromethane. The mixture was filtered and concentrated. To the dried compound (1.42 g) in 20 ml of dichloromethane was added 2.48 g of carbontetrabromide (CBr4, 7.47 mmol) and 1.50 g of triphenylphosphine (PPh3, 5.71 mmol). After stirring under an atmosphere of argon overnight, the reaction mixture was filtered through a silica gel bed, then concentrated and purified by silica gel chromatography. (EtOAc/Hexane Gradient starting at a ratio of 1:2 and changing to a ratio of 2:3) to yield 0.92 g of the 10a. (62%). Rf=0.64 (EtOAc); 1H NMR (CDCl3) 3.785 (t, 2H, J=6.3+6.3 Hz), 3.68 (t, 2H, J=6.5+6.5 Hz), 3.650 (m, 8H), 3.615 (m, 4H), 3.462 (t, 2H, J=6.3+6.4 Hz), 2.491 (t, 2H, J=6.5+6.5 Hz), 1.434 (s, 9H); 13C NMR 171.063, 80.656, 71.368, 70.831, 70.764, 70.706, 70.678, 70.545, 67.061, 36.431, 30.474, 28.263; MS m/z 408.74 (M+Na)+, 406.70, 405.70, 404.73.

Aufarbeitung

  1. dry with materialdried over anhydrous sodium sulfate and 4A molecular sieves in dichloromethane
  2. filtrationThe mixture was filtered
  3. concentrationconcentrated
  4. filtrationthe reaction mixture was filtered through a silica gel bed
  5. concentrationconcentrated
  6. custompurified by silica gel chromatography

Quellen und Nachweise

ORD-Eintrag
ord-b9175af2ab01437f8ad6dcf64f469d53
Quelldatensatz
uspto-grants-2004_04
Patentnummer
US06716821B2

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