Hydrochloric Acid → Methyl 2,6-di-O-benzyl-alpha-D-mannopyranoside

HRID 374603

Reaktionsgleichung

Reaktionsgleichung von HRID 374603
[O:1]([CH3:13])[C@H:2]1[O:10][C@H:9]([CH2:11][OH:12])[C@@H:7]([OH:8])[C@H:5]([OH:6])[C@@H:3]1[OH:4].CO[CH:16](OC)[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1.[C:25]1([CH3:35])[CH:30]=[CH:29][C:28](S(O)(=O)=O)=[CH:27][CH:26]=1.[BH4-].[Na+].Cl>C(#N)C>[CH2:16]([O:4][C@H:3]1[C@@H:5]([OH:6])[C@H:7]([OH:8])[C@@H:9]([CH2:11][O:12][CH2:35][C:25]2[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=2)[O:10][C@@H:2]1[O:1][CH3:13])[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1

Komponenten

7

Edukt 5

HCID 313Hydrochloric AcidHCID 6101p-Toluenesulfonic acidHCID 62375Benzaldehyde dimethyl acetalHCID 101798Methyl alpha-D-mannopyranosideHCID 4311764Sodium borohydride

Produkt 1

HCID 21604246Methyl 2,6-di-O-benzyl-alpha-D-mannopyranoside

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 6342AcetonitrileLösungsmittel

Versuchsvorschrift

A ca. 2:1 mixture of exo- and endo-isomers of bis-[(2,3-O-), (4,6-O-)]benzylidene-α-D-mannopyranoside (Carbohydrates, Ed. Collins, P. M., Chapman and Hall, New York, 1987, p. 350) was prepared by reaction of methyl α-D-mannopyranoside with 2.2 eq of α,α-dimethoxytoluene and catalytic p-toluenesulfonic acid in acetonitrile. This compound was treated with NaBH4 and HCl (Garegg, P. J.; Hultberg, H. Carbohydrate Res. 1981, 93, C10) to provide a mixture of products from which the methyl 2,6-O-benzyl-α-D-mannopyranoside was isolated by flash chromatography. The assignment of this isomer was confirmed by 1H decoupling experiments on the corresponding bis-(3,4-O-diphenylphosphino) derivative (ligand VA). 1H NMR δ7.42-7.24 (m, 10), 4.81 (d, 1, J=1 Hz), 4.75-4.54 (m, 4) 3.78-3.71 (m, 6), 3.36 (s, 3), 2.83 (bs, 1), 2.43 (bs, 1).

Aufarbeitung

  1. additionA ca. 2:1 mixture of exo- and
  2. custom1981, 93, C10) to provide
  3. customwas isolated by flash chromatography

Quellen und Nachweise

ORD-Eintrag
ord-f40bf4e1e15b4bd8852a362672087b80
Quelldatensatz
uspto-grants-1996_01
Patentnummer
US05481006

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