Bridge Ring Compound Nomenclature

 

The organic compound in which two or more cyclic rings fused together called Bridge Compound. Bicyclic compound in which two ring fused together.

The carbon atoms common to both the ring are called Bridge Head atoms and each chain of carbon atoms connecting both the bridge head atoms is called a Bridge or Bridge chain/ ring.

The bridge may contain 0, 1, 2, 3, 4…….etc, carbon atoms.

Example

 

 

IUPAC nomenclature of bridged compounds

It was establish by the von Baeyer system.

1. The root name is based on the number of C atoms in the ring structures.
2. The prefix bicyclo[a.b.c] is added where a, b and c are the total number of atoms in the bridge or bridge chain as discuss above.
3. The number of carbon atoms in each of the three bridge or bridge chain excluding the bridgehead atoms is indicate in square brackets separated form one another by full stops and arrange in their descending order.
4.  The square brackets is written between the prefix and root name
5. Note :- You may simplify structure to simple Carbon and Hyderogen boand
    

1. 
   Sample examples
   
   1.         
   
   ·        As a structure of bridge compound requires the prefix bicyclo
   ·     The total number of Carbon in ring structure is C 4 therefore root word is  = but
   ·        Functional group is an alkane, therefore suffix = -ane i.e butane
   ·        The three bridge contain 1, 0 and 1 carbon atoms therefore written as = [1.1.0]
   Name- bicyclo[1.1.0]butane
   
   
   
   
   2.         

·        As a structure of bridge compound requires the prefix bicyclo

·       The total number of Carbon in ring structure is C 8 therefore root word is  = oct

·        Functional group is an alkane, therefore suffix = -ane i.e Octane

·     The three bridge contain 4, 0 and 2 carbon atoms therefore written as = [4.2.0]

        Name- bicyclo[4.2.0]Octane

3.         

·        As a structure of bridge compound requires the prefix bicyclo 

·      The total number of Carbon in ring structure is C 5 therefore root word is  = Pent 

·      Functional group is an alkane, therefore suffix = -ane i.e pentane 

·    The three bridge contain 4, 0 and 2 carbon atoms therefore written as =[1.1.1]

 

        Name- bicyclo[1.1.1]pentane

4.           

                      ·     As a structure of bridge compound requires the prefix bicyclo 

   .  The total number of Carbon in ring structure is C 8 therefore root word is  = oct

·       Functional group is an alkane, therefore suffix = -ane i.e Octane

·    The three bridge contain 4, 0 and 2 carbon atoms therefore written as = [4.1.1]

 

       Name- bicyclo[4.1.1]Octane

5.        

·        As a structure of bridge compound requires the prefix bicyclo

·      The total number of Carbon in ring structure is C 9 therefore root word is  = non

·        Functional group is an alkane, therefore suffix = -ane i.e Nonane

·       The three bridge contain 3, 1 and  3 carbon atoms therefore written as = [3.3.1]

                 Name- Bicyclo[3.3.1]nonane

IUPAC nomenclature of substituted bridged compounds

 

5.  For  substituted  bicycloalkanes,  the  rings  are numbered starting  from one of the bridgehead carbon atom to the next bridgehead  proceeding through longest bridge ring system. It is then continued to the next longest bridge system and back to the first bridge carbon head. It is finally completed by the shortest ring system.

 

For example, in the structure shown above, the bridgehead atoms are C1 and C6.

The three links are x= C2,C3,C4,C5,

       y = C7,C8 and

the final link z has no atoms in it, so this is a [4.2.0] system.

Name- 3-methyl bicyclo[3.3.1]octane

 

6.                                 

·     As a structure of bridge compound requires the prefix bicyclo

·    The total number of Carbon in ring structure is C 7 therefore root word is  = hept

·  Functional group is an alkane, therefore suffix = -ane i.e Heptane

·The three bridge contain 3, 1 and  3 carbon atoms therefore written as = [2.2.1]

·     Substitution methyl group on 1 and 2 carbon atoms 

Name- 1,2-dimethyl bicyclo[2.2.1]heptan

7.         

·    As a structure of bridge compound requires the prefix bicyclo

·   The total number of Carbon in ring structure is C 7 therefore root word is  = hept

·        Functional group is an alkene, therefore suffix = -ane i.e Nonene

·     The three bridge contain 3, 1 and  1 carbon atoms therefore written as = [3.1.1]

·   Numbering the longest bridge chain found substitution at 2^nd position methyl group.

·        Indicate the position of double bond.

 

           Name- 2-methylbicyclo[3.1.1]hept-2-ene

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