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IUPAC stands for International Union of Pure and Applied Chemistry.

Nomenclature of organic compounds

Organic chemistry deals with a number of various compounds. A systematic method of naming has been established to clearly classify them, and it is known as the IUPAC system of nomenclature. The names are associated with the structure in this systematic nomenclature so that the listener or reader may derive the structure from the name.

IUPAC Nomenclature

According to the Guidelines set by IUPAC, the nomenclature of compounds must follow these steps:

  1. The Longest Chain Rule: The parent hydrocarbon must be identified and subsequently named. The parent chain belonging to the compound in question is generally the longest chain of carbon atoms, be it in the form of a straight chain or a chain of any other shape.
  2. The Lowest Set of Locants: The carbon atoms belonging to the parent hydrocarbon chain must be numbered using natural numbers and beginning from the end in which the lowest number is assigned to the carbon atom which carries the substituents.
  3. Multiple instances of the same substituent: Prefixes which indicate the total number of the same substituent in the given organic compounds are given, such as di, tri, etc.
  4. Naming of different substituents: In the organic compounds containing multiple substituents, the corresponding substituents are arranged in alphabetical order of names in the IUPAC nomenclature of organic compounds in question.
  5. The naming of different substituents present at the same positions: In the scenario wherein two differing substituent groups are present at the same position of the organic compound, the substituents are named in ascending alphabetical order.
  6. Naming Complex Substituents: Complex substituents of organic compounds having branched structures must be named as substituted alkyl groups whereas the carbon which is attached to the substituent group is numbered as one. These branched and complex substituents must be written in brackets in the IUPAC nomenclature of the corresponding compounds.

The format of the IUPAC Name of the Compound can be written as: Locant + Prefix + Root + Locant + Suffix

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