page_title: Glycosidic bond
section_title: S-, N-, C-, and O-glycosidic bonds
hierarchical_section_title: Glycosidic bond / S-, N-, C-, and O-glycosidic bonds
context_page_description: A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate molecule to another group, which may or may not be another carbohydrate.
  A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide and the hydroxyl group of some compound such as an alcohol. A substance containing a glycosidic bond is a glycoside.
  The term 'glycoside' is now extended to also cover compounds with bonds formed between hemiacetal groups of sugars and several chemical groups other than hydroxyls, such as -SR, -SeR, -NR¹R², or even -CR¹R²R³.
  Particularly in naturally occurring glycosides, the compound ROH from which the carbohydrate residue has been removed is often termed the aglycone, and the carbohydrate residue itself is sometimes referred to as the 'glycone'.
context_section_description: Glycosidic bonds of the form discussed above are known as O-glycosidic bonds, in reference to the glycosidic oxygen that links the glycoside to the aglycone or reducing end sugar. In analogy, one also considers S-glycosidic bonds (which form thioglycosides), where the oxygen of the glycosidic bond is replaced with a sulfur atom. In the same way, N-glycosidic bonds, have the glycosidic bond oxygen replaced with nitrogen. Substances containing N-glycosidic bonds are also known as glycosylamines. C-glycosyl bonds have the glycosidic oxygen replaced by a carbon; the term "C-glycoside" is considered a misnomer by IUPAC and is discouraged. All of these modified glycosidic bonds have different susceptibility to hydrolysis, and in the case of C-glycosyl structures, they are typically more resistant to hydrolysis.
caption: Adenosine, a component of RNA,  results from the sugar ribose and adenine via the formation of an N-glycosidic bond (shown as the vertical line between the N and the sugar cycle)