heterosyklisten
Heterosyklisten are cyclic organic compounds in which one or more ring atoms are heteroatoms—typically nitrogen, oxygen, or sulfur—instead of carbon. The term is commonly shortened to heterocycles in English. Heteroatoms alter the electronic structure, basicity, and hydrogen-bonding properties of the ring, giving rise to a wide range of reactivity. Consequently, heterocycles are among the most prevalent motifs in chemistry and biochemistry.
Classification and examples: Five-membered rings include pyrrole, furan, and thiophene, as well as nitrogen-containing systems such
Occurrence and significance: Many natural products and vitamins contain heterocycles. Nucleic acids are built on fused
Properties and synthesis: The presence of heteroatoms influences basicity, acidity, polarity, and nucleophilicity. Heterocycles can be
See also: heteroaromatic compounds, pharmacophore, and related nomenclature.