IUPAC systems of nomenclature of organic compounds

• IUPAC Systems (International Union of Pure and Applied Chemistry) has established a standardized system for naming organic compounds, ensuring clear and unambiguous communication among chemists.
• IUPAC system applies to open-chain (aliphatic) compounds, carbocyclic compounds, and compounds containing functional groups.
• Below is a concise overview of the IUPAC systems nomenclature system for organic compounds with up to 10 carbon atoms.

Open-Chain (Aliphatic) Compounds

1. Alkanes (Saturated Hydrocarbons)

   • Alkanes are hydrocarbons with only single bonds between carbon atoms.
   • Naming rule: Prefix (indicating the number of carbon atoms) + suffix “-ane”.
     • 1 carbon: Meth-
     • 2 carbons: Eth-
     • 3 carbons: Prop-
     • 4 carbons: But-
     • 5 carbons: Pent-
     • 6 carbons: Hex-
     • 7 carbons: Hept-
     • 8 carbons: Oct-
     • 9 carbons: Non-
     • 10 carbons: Dec-
   • Example: “Pentane” for a hydrocarbon with five carbon atoms.

2. Alkenes and Alkynes (Unsaturated Hydrocarbons)

   • Alkenes: Have one or more double bonds.
   • Alkynes: Have one or more triple bonds.
   • Naming rule: Suffix “-ene” for alkenes, “-yne” for alkynes. The position of the multiple bond is indicated by a number.
   • Examples:
     • “Pent-2-ene” (five-carbon chain, double bond between the second and third carbons).
     • “Pent-1-yne” (five-carbon chain, triple bond between the first and second carbons).

Carbocyclic Compounds

1. Cycloalkanes (Saturated)

   • Cycloalkanes are cyclic hydrocarbons with only single bonds.
   • Naming rule: Prefix “cyclo-” + alkane name (based on the number of carbon atoms in the ring).
   • Example: “Cyclohexane” for a six-carbon ring.

2. Cycloalkenes (Unsaturated)

   • Cycloalkenes contain at least one double bond in the ring.
   • Naming rule: Prefix “cyclo-” + suffix “-ene”, with numbers indicating the position of the double bond.
   • Example: “Cyclohex-1-ene” for a six-carbon ring with a double bond between the first and second carbons.

Naming Substituents and Functional Groups

• Substituents and functional groups are named with prefixes or suffixes, and their positions on the chain or ring are indicated by numbers. Below are common functional groups:
  • Alcohol: Suffix “-ol” (e.g., ethanol) or prefix “hydroxy-“.
  • Amine: Suffix “-amine” (e.g., methylamine) or prefix “amino-“.
  • Aldehyde: Suffix “-al” (e.g., formaldehyde) or prefix “formyl-“.
  • Ketone: Suffix “-one” (e.g., propanone) or prefix “oxo-“.
  • Carboxylic Acid: Suffix “-oic acid” (e.g., acetic acid) or prefix “carboxy-“.
  • Ester: Suffix “-oate” (e.g., ethyl acetate).

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