Publication

Synthesis of α-D-(1→3) and α-D-(1→4)-C-linked galactosides of D-mannose derivatives. Conformation of α-C-galactosides

Pierre Vogel
1994
Journal Articles

Abstract

Reductive radical alpha-D-galactosidation of 5-exo-(benzeneselenyl)-6-endo-chloro-3-methylidene-7- -oxabicyclo[2.2.1]heptan-2-one with acetobromo-D-galactose, followed by ketone reduction led to (+)-(1R,2S, 3R,4S,5S,6S)-5-exo-(benzeneselenyl)-6-endo-chloro-3-endo-[(2',3',4',6'-t etra-O-acetyl-alpha-D-galactopyranosyl)me- thyl]-7-oxabicyclo[2.2.1]heptan-2-endo-ol which was converted into (+)-methyl 3-deoxy-3-[(alpha-D-galactopyranosyl)methyl]-alpha-D-mannopyranoside (1), (+)-3-deoxy-3-[alpha-D-galactopyranosyl)methyl]-D-mannitol (2) and 4-deoxy-4-[(2',3',4',6'-tetra-O-acetyl-alpha-D-galactopyranosyl)methyl]- 2,3,6-tri-O-acetyl-D-mannono-1,5-lactone (3). H-1-MNR data of the alpha-C-galactosides confirmed that their preferred conformations involve antiperiplanar arrangements for the C-linked substrates and bond sigma C(1'),C(2') of the alpha-(1-->3)-C-galactoside unit. The alpha-(1-->3)-C-galactoside of methyl mannopyranoside 1 adopts a conformation similar to that proposed for methyl 3-O-(alpha-D-galactopyranosyl)-alpha-D-mannopyranoside.

Official source

https://infoscience.epfl.ch/entities/publication/81fd9287-c879-4f1b-b518-3dbc83a7c0fb

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Pierre Vogel
1994
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/81fd9287-c879-4f1b-b518-3dbc83a7c0fb

About this result

Related concepts (20)

Β-Galactosidase

β-Galactosidase (EC 3.2.1.23, lactase, beta-gal or β-gal; systematic name β-D-galactoside galactohydrolase), is a glycoside hydrolase enzyme that catalyzes hydrolysis of terminal non-reducing β-D-galactose residues in β-D-galactosides. β-Galactosides include carbohydrates containing galactose where the glycosidic bond lies above the galactose molecule. Substrates of different β-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins.

X-gal

X-gal (also abbreviated BCIG for 5-bromo-4-chloro-3-indolyl-β--galactopyranoside) is an organic compound consisting of galactose linked to a substituted indole. The compound was synthesized by Jerome Horwitz and collaborators in 1964. The formal chemical name is often shortened to less accurate but also less cumbersome phrases such as bromochloroindoxyl galactoside. The X from indoxyl may be the source of the X in the X-gal contraction.

Sigma bond

In chemistry, sigma bonds (σ bonds) are the strongest type of covalent chemical bond. They are formed by head-on overlapping between atomic orbitals. Sigma bonding is most simply defined for diatomic molecules using the language and tools of symmetry groups. In this formal approach, a σ-bond is symmetrical with respect to rotation about the bond axis. By this definition, common forms of sigma bonds are s+s, pz+pz, s+pz and dz2+dz2 (where z is defined as the axis of the bond or the internuclear axis).