IUPAC Naming Conventions

Naming Steps

1. Identify the longest carbon chain containing the highest order functional group
   • Called the parent chain and is what is used to determine the root of the name
   • Consider double and triple bonds when identifying highest-order functional group
   • Highest-priority functional group provides suffix
   • If there are two or more chains of equal length, the most substituted chain gets priority
2. Number the chain
   • Carbon 1 is the closest to the high-priority functional groups
   • If all functional groups have the same priority, make the substituted carbons as low as possible
   • The more oxidized the carbon is, the higher priority it has in the molecule
   • Oxidation state increases with more bonds to heteroatoms and decreases with more bonds to hydrogen
   • Heteroatoms → atoms besides carbon and hydrogen
3. Name the substituents
   • Substituents → functional groups that are not part of the parent chain
   • Substituents' name goes at the beginning of the molecule as a prefix
   • Named like alkanes, but with -yl instead of ane
   • If multiple of the same substituent, prefix (di, tri, tetra)
4. Assign a number to each substituent
   • Pair substituent to corresponding numbers in the parent chain
5. Complete the name
   • Name the substituents in alphabetical order
   • Numeric prefixes do not need to be alphabetised, but things like iso, neo, and cyclo do
   • Numbers separate words with commas, words from words with hyphens
   • Finish with name of backbone chain with suffix for functional group of highest priority

Hydrocarbons and Alcohols

Alkanes

• Simple hydrocarbon molecules with the formula $C_nH_{(2n+2)}$
• Methane - 1 carbon, Ethane - 2 carbons, Propane - 3 carbons, Butane - 4 carbons
• 5+ are named with their Greek prefix (pent-, hex-, etc)
• Halogens are common substituents on alkanes and are indicated by prefix (fluoro, chloro, bromo, iodo)

Alkenes and Alkynes

• Alkene → has a double bond
• Alkyne → has a triple bond
• Unsaturated fatty acids, biochemical compounds → often have double bonds
• Double and triple bonds are named like a substituent, indicated by lower-numbered bond
• Number can proceed molecule name (2-butene) or be in the middle (but-2-ene)