Chem bio cc 2

• The International Union of Pure and Applied Chemistry (IUPAC) was established in 1919 to make sure that chemists around the world could communicate accurately
• Many chemicals had common names given to them by the people who discovered them based on their source or smell or color
• Common names don't tell you much about the chemical structure
• IUPAC has a set of rules for systematic naming of organic chemicals
• Steps for IUPAC systematic naming

  1. Find the longest carbon chain and give it a root name

  2. Identify the highest priority functional group and add its suffix to the root name

  3. Identify the types of substituents and their positions on the carbon chain, then add a numbered prefix to the root name
• Root names for carbon chains

  1 carbon = meth-

  2 carbons = eth-

  3 carbons = prop-

  4 carbons = but-

  1. 12 carbons = pent-, hex-, hept-, oct-, non-, dec-, undec-, dodec-
• Hydrocarbon types


  Alkanes (single bonds)

  Alkenes (double bonds)

  Alkynes (triple bonds)

  Aromatics
• Naming alkenes


  Find the longest carbon chain

  Number the carbons starting from the end closest to the double bond

  Use the lowest number touching the double bond and add the suffix -ene to the root name
• Naming alkynes


  Find the longest carbon chain

  Number the carbons starting from the end closest to the triple bond

  Use the lowest number touching the triple bond and add the suffix -yne to the root name
• Naming substituents


  Identify the substituents and their positions

  Add a numbered prefix to the root name

  Put substituent prefixes in alphabetical order
• Halogens get the -ine in their name replaced with -o (e.g. chlorine becomes chloro-)
• When an alkene and alkyne tie for lowest number, the alkene takes priority
• Dichloromethane


  Alkane with two chlorine atoms attached to the single carbon
• Methylene chloride


  Common name for a CH2 group with two chlorine atoms
• Systematic names are more useful for chemists than common names