Methanol → methyl 2,3,5-tri-O-benzyl-L-xylofuranoside

HRID 985349Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 985349
[O:1]([CH3:11])[CH:2]1[O:8][C@@H:7]([CH2:9][OH:10])[C@@H:5]([OH:6])[C@@H:3]1O.[H-].[Na+].[CH2:14](Br)[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1.[CH3:22][OH:23]>O1CCCC1.[I-].C([N+](CCCC)(CCCC)CCCC)CCC>[CH2:22]([O:23][C@H:3]1[C@H:5]([O:6][CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)[C@H:7]([CH2:9][O:10][CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)[O:8][CH:2]1[O:1][CH3:11])[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1

Komponenten

7

Edukt 4

HCID 887MethanolHCID 7498Benzyl BromideHCID 24758Sodium hydrideHCID 12042993methyl L-xylofuranoside

Produkt 1

HCID 11015596methyl 2,3,5-tri-O-benzyl-L-xylofuranosideAusbeute 87 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 67553Tetrabutylammonium IodideKatalysatorHCID 8028TetrahydrofuranLösungsmittel

Versuchsvorschrift

To an ice-cold solution of 2 (10 g, 60.9 mmol) in dry tetrahydrofuran (350 mL) was added sodium hydride (60% dispersion in mineral oil, 14.8 g, 370 mmol) and the reaction mixture was stirred for 15 min under N2. To this reaction mixture was added solid tetrabutylammonium iodide (0.36 g, 0.96 mmol) followed by a dropwise addition of benzyl bromide (36.6 g, 214 mmol). The reaction mixture was stirred for 3 days at room temperature. After the addition of methanol (25 mL) the solution was evaporated under reduced pressure, and the crude product was purified by silica gel chromatography (cyclohexane/EtOAc, 9:1) to afford pure methyl 2,3,5-tri-O-benzyl-L-xylofuranoside (3, 23 g, 87% yield). MS 435 (M+H)+, 433 (M−H)+, 403 (M−OCH3)+; 1H NMR (CDCl3) δ 7.38-7.25 (m, 30H, aromatic H=s), 4.94 (d, 1H, H-1α, J1,2=4.3 Hz), 4.87 (d, 1H, H-1β, J1,2=0.9 Hz), 4.64-4.45 (m, 12H, PhCH2′s), 4.37 (m, 1H, H-4α), 4.27 (dt, 1H, H-4β, J4,5a=3.7 Hz, J4,5b=6.5 Hz, J3,4=6.2 Hz), 4.17 (t, 1H, H-3α, J3,4=6.9 Hz, J2,3=5.6 Hz), 4.07 (dd, 1H, H-3β, J3,4=6.2 Hz, J2,3=2.5 Hz), 4.00 (dd, 1H, H-2α, J2,3=5.6 Hz), 3.95 (t, 1H, H-2β, J2,3=2.5 Hz), 3.70 (dd, 1H, H-5aα, J4,5a=4.5 Hz, J5a,5b=10.4 Hz), 3.66 (dd, 1H, H-5aβ, J4,5a=3.7 Hz, J5a,5b=10.7 Hz), 3.54 (dd, 1H, H-5bα, J4,5b=7.5 Hz), 3.49 (dd, 1H, H-5bβ, J4,5b=6.5 Hz).

Aufarbeitung

  1. stirringThe reaction mixture was stirred for 3 days at room temperature
  2. customwas evaporated under reduced pressure
  3. customthe crude product was purified by silica gel chromatography (cyclohexane/EtOAc, 9:1)

Quellen und Nachweise

ORD-Eintrag
ord-ab95c5a6becd43e29a35a2de29dbd4b6
Quelldatensatz
uspto-grants-2005_03
Patentnummer
US06870052B2

Notizen zur Reaktion

Wird geladen…