Ethyl 4,6-O-benzylidene-1-thio-α-D-glucopyranoside

Ethyl 4,6-O-benzylidene-1-thio-α-D-glucopyranoside

Ethyl 4,6-O-benzylidene-1-thio-α-D-glucopyranoside is a carbohydrate derivative widely used in synthetic organic chemistry, particularly as a glycosyl donor in stereoselective glycosylation reactions. Its structural features and protective groups make it a valuable intermediate for constructing complex oligosaccharides and glycoconjugates.

Chemical Identity

• Molecular Formula: C₁₅H₂₀O₅S
• Molecular Weight: 312.38 g/mol
• Key Functional Groups:
  • Thioether linkage at the anomeric position for stability and controlled activation.
  • Benzylidene acetal at the 4,6-hydroxyl groups to maintain a rigid conformation.
  • Ethyl group at the anomeric sulfur for hydrophobicity and reactivity.

Structural Features

1. Thioether Linkage at Anomeric Position:
   • The sulfur atom replaces the typical oxygen in glycosides, forming a thioglycoside. This substitution enhances stability and allows selective activation under mild conditions using promoters such as NIS/TfOH.
2. 4,6-O-Benzylidene Acetal:
   • Protects the hydroxyl groups at C-4 and C-6, locking the sugar ring in a rigid bicyclic structure that minimizes steric hindrance and facilitates stereoselective glycosylation.
3. α-Anomeric Configuration:
   • The α-configuration ensures specific stereochemical outcomes during glycosylation reactions, making it suitable for synthesizing α-linked oligosaccharides.

Applications

This compound is particularly useful in carbohydrate synthesis due to its tailored reactivity and protective groups:

• Glycosylation Reactions: Acts as a glycosyl donor in stereoselective synthesis of oligosaccharides and glycoconjugates. The thioether linkage allows for precise activation, enabling controlled formation of glycosidic bonds.
• Intermediate for Complex Molecules: Used in the synthesis of biologically active natural products, glycolipids, and glycoproteins.
• Protective Group Manipulation: The benzylidene group can be selectively removed under acidic conditions to expose the hydroxyl groups for further functionalization.

Reactivity Profile

The compound’s reactivity is influenced by its protective groups:

• The benzylidene acetal ensures stability during multi-step syntheses while allowing selective deprotection when needed.
• The thioether linkage provides enhanced stability compared to standard glycosides but remains reactive under specific activation conditions.

Physical Properties

• Appearance: Typically a crystalline solid or powder.
• Solubility: Soluble in common organic solvents such as dichloromethane or chloroform due to its hydrophobic protective groups.

This compound exemplifies advanced design in carbohydrate chemistry, offering tailored reactivity for constructing complex oligosaccharides and glycoconjugates with applications in medicinal chemistry and materials science.

Citations:

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC3011798/
2. https://www.lookchem.com/casno19526-09-1.html