Arenes: Arenes are aromatic hydrocarbons—a class of organic compounds containing one or more special rings of carbon atoms with delocalized pi electrons. They are cyclic unsaturated (having atleast one double or triple bonds) organic compunds.
Key Features
- Structure: Built on flat, cyclic rings (such as benzene rings) with alternating single and double bonds that achieve special stability through resonance.
- The Term "Aromatic": Originally described sweet-smelling plant extracts, but today it defines electronic stability and ring conjugation rather than odor.
- Properties: Typically hydrophobic (water-fearing), non-polar, and prone to burning with a sooty flame due to a high carbon-to-hydrogen ratio.
Why Markovnikov rule applies only to asymmetric alkenes:
Just like haloalkanes are classified as primary, secondary and tertiary according to the nature of carbon atom to which halogen atom is attached, amines are also classified as primary, secondary and tertiary.
For example in above diagram, Aniline is a primary aromatic amine, n-methylbenzenamie is a secondary aromatic amine and n,n dimethylbenzenamine is a tertiary aromatic amine.
The Amino functional group -NH2
Notice that Benzenediamine is not a secondary amine.
Meaning of 'in situ' reaction:
