N-bromobutanimide → Isohexane ethyl acetate

HRID 130007

Reaktionsgleichung

Reaktionsgleichung von HRID 130007
S1C=C[CH:3]=[C:2]1[C@:6]1(O[C@H](CO)[C@@H:11]([O:12][C@@H:13]2[O:30][C@H](COCC3C=CC=CC=3)[C@H](OC(=O)C)[C@H](OC(=O)C)[C@H:14]2OC(=O)C)[C@H:9](O)[C@@:8]1([C@@H:48]1O[C@@H](C)[C@@H](OCC2C=CC=CC=2)[C@@H](OCC2C=CC=CC=2)[C@@H]1OCC1C=CC=CC=1)NC(=O)C)O.CN(S(F)(F)F)C.BrN1C(=O)CCC1=O>ClCCl>[C:13]([O:12][CH2:11][CH3:9])(=[O:30])[CH3:14].[CH3:3][CH2:2][CH2:6][CH:8]([CH3:48])[CH3:9]

Komponenten

5

Edukt 3

HCID 67184N-bromobutanimideHCID 123203Sulfur, trifluoro(N-methylmethanaminato)-HCID 1317192141-Thiophenyl-(2,3,4-tri-O-acetyl-6-O-benzyl-beta-D-galactopyranosyl)-(1-4)-[(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-(1-3)]-2-deoxy-2-acetamido-beta-D-glucopyranose

Produkt 1

HCID 21882781Isohexane ethyl acetate

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 6344DichloromethaneLösungsmittel

Versuchsvorschrift

Compound [18] (0.25-6.2 g, 0.2-4.91 mmol) is taken up in dry dichloromethane (3-85 ml) and, at -78° C., dimethylaminosulfur trifluoride (0.08-1.93 g, 0.6-14.73 mmol) and N-bromosuccinimide (0.05-1.23 g, 0.28-6.87 mmol) are added, and the mixture is warmed to room temperature. After washing with saturated sodium bicarbonate solution, the mixture is concentrated and the byproducts of the reaction are removed by silica gel chromatography (stepwise gradient: ethyl acetate/isohexane) giving compound [22] (0.33-6.47 g, 0.72-14.4 mmol, about 80% yield). The reaction product is dissolved in dichloromethane and, at -78° C., o-nitrobenzyl alcohol (0.08-1.88 g, 0.5-12.28 mmol), 4 Å molecular sieves (0.1-7.5 g), silver trifluoromethanesulfonate (0.18-4.42 g, 0.7-17.19 mmol) and hafnocene dichloride (0.27-6.53 g, 0.7-17.19 mmol) are added, and the mixture is allowed to warm to room temperature. Filtration is followed by washing with saturated sodium bicarbonate solution and concentration. The crude product obtained in this way is purified by chromatography on silica gel (dichloromethane/methanol gradient) and dissolved in dry methanol (3-80 ml), and catalytic amounts of sodium methylate (prepared from 0.001-0.09 g of sodium methylate (prepared from 0.001-0.09 g of sodium in 0.2-2.5 ml of methanol) are added. After the reaction is complete, the mixture is neutralized with an acidic ion exchanger (0.2-6.5 g Amberlite IR-120, H+ -form). Evaporation results in compound [23]. FAB-MS: M+H+ =1186. NMR data consistent with Nicolaou et al., J. Am. Chem. Soc. 114:3127 (1992) and C. W. Hummel, Ph.D. Dissertation, University of California, San Diego (1993).

Aufarbeitung

  1. washAfter washing with saturated sodium bicarbonate solution
  2. concentrationthe mixture is concentrated
  3. customthe byproducts of the reaction are removed by silica gel chromatography (stepwise gradient

Quellen und Nachweise

ORD-Eintrag
ord-35eb95ae8b7745d7af9494440ffc2180
Quelldatensatz
uspto-grants-1995_11
Patentnummer
US05470843

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