Sugar-amino acid hybrids are molecules that combine the structural features of simple amino acids with those of simple carbohydrates. The resulting hybrid is a highly substituted, polyfunctionalized building block which can be used to create novel materials with potential applications as glycomimetics, artificial amino acids and peptides. Sugar-amino acid hybrids occur in nature in various forms and are components of several antibacterial, antiviral and antifungal agents. Unnatural sugar-amino acid hybrids can be accessed through incorporation of a carbohydrate-based 5- or 6-membered scaffold into the side chains of amino acids. Additional manipulation on the carbohydrate scaffolda may be used to adjust the physical and dynamic properties of the resulting hybrid. Substitution of amino acid building blocks by sugar-amino acid hybrids in peptides allows the engineering of carbohydrate-binding sites into synthetic peptides. This might be a useful route to overcome some of the drawbacks associated with peptide-based drug design such as proteolytic cleavage, poor transport properties, and unselective receptor discrimination.
This review describes the research and development of microbial resolution for chiral C3 and C4 synthons production. These chiral C3 and C4 synthons are now mainly used for various pharmaceuticals and new materials such as synthesis of liquid crystals. As a result, we developed a production process for useful and common C3 chiral synthons with higher optical purity (>98%ee), such as optically active 2, 3-dichlolo-l-propanol (DCP*), epichlorohydrin (EP*), glycidol (GLD*) and its precursor, 3-chloro-1, 2-propandiol (CPD*). Moreover, we also investigated other useful chiral C4 synthons with higher optical purity (>98%ee), such as optically active 4-chloro-3-hydroxybutyronitrile (BN*), 4-chloro-3-hydroxybutyrate (CHB*), and 3-hydroxy-γ-butyrolactone (HL*). On the other hand, some dehalogenating enzymes involved in the microbial resolution were elucidared, purified and characterized. The two kinds of purified dehaloganating enzymes were found to belong to dehydrogenase and carboxylate hydrolase, respectively. Furthermore, development of production of chiral 1, 2-diols and, α-and β-hydroxycarboxylates was successfully done using these two enzymes.
The fluorous-tag method is a methodology which could purify product by partitioning the product mixture between a fluorous solvent such as perfluorohexane and an organic solvent, and is an excellent strategic alternative to solid-phase synthesis. In this report, the fluorous-tag method is initially described. The possibility of oligosaccharide synthesis using fluorous-tag method is then discussed.
Endo-M is one of the enzymes known as endo-β-N-acetylglucosaminidases. This enzyme was found by Yamamoto et al., in the culture fluid of Mucor hiemalis isolated from soil. Endo-M is a remarkably effective enzyme for the study of oligosaccharides. This article introduces some interesting examples of its usage, and describes the large-scale production method of the enzyme.