- Basic aromatic ring
Basic aromatic rings are aromatic rings in which the
lone pair ofelectron s of a ring-nitrogen atom is not part of thearomatic system and extends in the plane of the ring. This lone pair is responsible for the basicity of thesenitrogenous base s, similar to the nitrogen atom inamine s. In these compounds the nitrogen atom is not connected to ahydrogen atom. Basic aromatic compounds get protonated and form aromaticcation s (e.g.pyridinium ) underacid ic conditions. Typical examples of basic aromatic rings arepyridine orquinoline . Several rings contain basic as well as non-basic nitrogen atoms, e.g.imidazole andpurine .In non-basic aromatic rings the
lone pair ofelectron s of the nitrogen atom is delocalized and contributes to the aromaticpi electron system. In these compounds the nitrogen atom is connected to ahydrogen atom. Examples of non-basic nitrogen-containing aromatic rings arepyrrole andindole .The basic aromatic rings
purine s andpyrimidine s are thenucleobases found inDNA andRNA .See also
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Simple aromatic ring
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