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What is the name of what looks like a benzene ring but one of the carbons is replaced with a nitrogen?
http://www.dcu.ie/~chemist/pratt/annulene/annulene.htmJust as a carbon atom in a hydrocarbon chain can be replaced by heteroatoms to give, for example, ethers or amines, so can the carbons of aromatic rings such as those described above be replaced by heteroatoms to give HETEROAROMATIC systems.
Nitrogen as replacement heteroatom in benzene:
To formally replace a C atom of benzene, nitrogen must fulfill the same orbital and electronic criteria as the carbon it is to replace, i.e. it must be sp2-hybridised and have the same number of electrons (the principle of isoelectronic replacement).
Replacing one carbon with a nitrogen yields pyridine.
Replacing two carbons in different positions can yield a variety of componds like pyridazine (1,2-diazine), pyrimidine (1,3-diazine), or pyrazine (1,4-diazine).
Replacing three carbons with three nitrogens generates 1,3,5-triazine and replacing four carbons by four nitrogens produces 1,2,4,5-tetrazine.
Oxygen as replacement heteroatom in benzene:
For oxygen to achieve the same orbital and electronic requirements as a carbon in benzene it has to lose an electron becoming O+. By replacing one carbon in benzene with an O+, a pyrilium cation is formed.
Sulphur as replacement heteroatom in benzene:
For sulphur to achieve the same orbital and electronic requirements as carbon it also has to lose an electron becoming S+. By replacing one carbon in benzene with an S+, a thiopyrilium cation is formed.
An organic ring is a structural arrangement of atoms in an organic molecule, where the atoms are bonded together in a closed loop or ring formation. This type of molecule is commonly found in organic compounds such as carbohydrates, lipids, and proteins.
The purpose of an organic ring can vary depending on the specific molecule it is a part of. Generally, organic rings play important roles in the function and structure of organic compounds. For example, in proteins, organic rings can act as binding sites for other molecules, while in carbohydrates, they can provide structural support.
There are various types of organic rings, each with their own unique properties and functions. Some common types include aromatic rings, heterocyclic rings, and cyclic alkanes. These rings can differ in the types of atoms present and the number and arrangement of bonds between them.
The naming of organic rings follows a specific set of rules and conventions, just like other organic compounds. The name typically reflects the number of carbon atoms in the ring, the type of bonds present, and any functional groups attached to the ring. For example, a six-carbon ring with alternating single and double bonds would be named "cyclohexene".
There are many examples of organic rings in nature and in synthetic compounds. Some well-known examples include the ring structures in glucose and fructose (both sugars), the heme ring in hemoglobin (a protein in red blood cells), and the benzene ring found in many aromatic compounds.