Direct Amidation of Aldoses and Decarboxylative Amidation of alpha-Keto Acids: An Efficient Conjugation Method for Unprotected Carbohydrate Molecules
Date Issued
2009
Date
2009
Author(s)
Cho, Chia-Chin
Abstract
Carbohydrates are essential materials in many biological processes. They can maintain and modulate the intrinsic properties of proteins. Glycoconjugates have become popular tools to investigate the biological processes. Many conjugation methods have been developed by anchoring carbohydrates to proteins. However, some of these methods may be time-consuming and result in low overall yield due to many preparation steps. ere we report a direct conjugation method by forming a robust amide bond between amine and aldehyde on the reducing end of aldose. By using iodine, an aldose was directly coupled with an amine through an amide bond in aqueous solution. Accordingly, aldoses undergo an oxidative amidation with a variety of aliphatic amines, bifunctional amines, α-amino esters, and peptides.nder this condition, the hydroxy groups on sugar skeleton are unaffected, the glycosidic bonds of the oligosaccharides are retained, and the amidation selectively occurs at the reducing end without interfering with other functional groups, e.g., the carboxy group in glucuronic acid. Various groups, such as double bond, phenyl, and ester are also inert in this condition. Furthermore, this reaction protocol was applied to conjugation of α-keto acids with amines by a sequence of decarboxylation, oxidation, and in situ amidation. It was promising to utilize this novel conjugation method for preparation of neoglycoproteins and neoglycolipids from unprotected and unmodified carbohydrates.
Subjects
amidation
iodine
aldose
ketoacid
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-98-D94223005-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):e594bed0dc854c61611dd88ba44e2ebe