1,2-Dibromobutane → Tert-butyl 2,3-dihydro-1,4-benzoxazine-4-carboxylate

HRID 1765051

Reaktionsgleichung

Reaktionsgleichung von HRID 1765051
[C:1]([O:5][C:6]([NH:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=1[OH:15])=[O:7])([CH3:4])([CH3:3])[CH3:2].C(=O)([O-])[O-].[K+].[K+].Br[CH2:23][CH:24](Br)CC>CC(C)=O>[C:1]([O:5][C:6]([N:8]1[C:9]2[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=2[O:15][CH2:24][CH2:23]1)=[O:7])([CH3:4])([CH3:2])[CH3:3]

Komponenten

5

Edukt 3

HCID 107921,2-DibromobutaneHCID 11430Potassium CarbonateHCID 4935485N-Boc-2-aminophenol

Produkt 1

HCID 15348605Tert-butyl 2,3-dihydro-1,4-benzoxazine-4-carboxylateAusbeute 82 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 180AcetoneLösungsmittel

Versuchsvorschrift

A solution of dry acetone (100 mL) containing N-(tertbutoxycarbonyl)-2-aminophenol (0.722 g, 3.69 mmol), potassium carbonate (10.2 g, 73.8 mmol) and 1,2-dibromobutane (2.54 mL, 29.6 mmol) was refluxed for 18 h. The reaction was monitored by TLC (petrol/ether 8/2). After cooling, the mixture was filtered through celite. After concentration and hydrolysis, the aqueous layer was extracted with EtOAc (3×40 mL), dried over MgSO4 and the solvent was removed under reduce pressure. The crude product was purified by flash chromatography on silica gel (petrol/EtOAc 95/5) to yield the title compound as a white solid (0.70 g, 82%). m.p=78-79° C.; Rf=0.44(petrol/ether 8/2); LCMS m/z 236 ([M+1]+); 1H NMR (300 MHz, CDCl3): δ 1.59 (9H, s); 3.87 (4H, m); 4.26 (4H, m); 6.86-7.02 (4H, m); 13C NMR (75 MHz, CDCl3): δ 27.4 (3C); 41.1; 64.6(2C); 80.6 (2C); 116.0; 119.2; 122.6; 123.4; 125.2; 144.9; 151.6. IR (film): 2975; 1696; 1494; 1143 cm−1.

Aufarbeitung

  1. temperaturewas refluxed for 18 h
  2. temperatureAfter cooling
  3. filtrationthe mixture was filtered through celite
  4. concentrationAfter concentration and hydrolysis
  5. extractionthe aqueous layer was extracted with EtOAc (3×40 mL)
  6. dry with materialdried over MgSO4
  7. customthe solvent was removed
  8. customThe crude product was purified by flash chromatography on silica gel (petrol/EtOAc 95/5)

Quellen und Nachweise

ORD-Eintrag
ord-14f3718280c74c5b937446c0d52ed94d
Quelldatensatz
uspto-grants-2007_06
Patentnummer
US07226918B2

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