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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Types of Carbon based on attachment

Primary, Secondary and Tertiary Carbon Atom

Primary carbon atom

If a carbon atom attached to functional group is directly attached to only one carbon atom, then it is said to be a "Primary carbon atom" or "1^o C-atom".

SECONDARY CARBON ATOM

If a carbon attached to functional group is directly attached to the two C-atoms, then it is said to be "Secondary carbon atom" or 2^o C-atom".

Tertiary Carbon Atom

If the carbon atom that is attached to a functional group is directly attached to three C-atoms, then it is said to be a "Tertiary carbon atom" or "3^o C-atom".

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MCQ Multiple Choice Question of Pharmaceutical Organic chemistry

MCQ Multiple Choice Question of Pharmaceutical Organic chemistry

1. The analgesic action of aspirin is removed, if

a. Carboxyl group is removed
b. Acetoxy group is removed
c. Carboxyl group is not attached on ortho position
d. All of the above

2. Caffeine is presented as a/an

a. Purine derivative
b. Pyrimidine derivative
c. Imidazole derivative
d. both b and c

3. A group that can donate an electron pair is

a. Bronsted acid
b. Bronsted base
c. Lewis acid
d. Lewis base

4. Which one of most acidic among the following

a. Propynoic acid

b. Propenoic acid 

c. Propanoic acid

5. Hendersen-Hasselbalch equation is represented by

a. Ka = [A][H+]/[HA]
b. pKa + pKb = 14
c. pKa = pH + log [HA]/[A-]
d. both a and c

6. Which of the following is through space-effects on polarizability due to electronegativity differences?

a. Field effect
b. Resonance effect
c. Inductive Effect
d. Polarizability

7. Which of the following is the ease of distortion of the electron cloud?

a. Field effect
b. Inductive Effect
c. Resonance effect
d. Polarizability

8. Which of the following occurs as a result of electronegativity differences?

a. Field effect
b. Inductive Effect 

c. Resonance effect
d. None of the above

9. Which of the following involves the actual movement of electrons through a pie-bond system?

a. Field effect
b. Inductive Effect 

c. Resonance effect
d. None of the above

10. The movement of electrons through a conjugated system allows for charges to be dispersed over several atoms. This phenomenon is

a. Localization
b. Delocalization
c. Polarization
d. Depolarization

11. Which of the following is less influenced by distance?

a. Field effect
b. Inductive Effect
c. Resonance effect
d. both a and c

12. Which of the following is a carbonyl based group?

a. esters
b. nitro-
c. alcohols
d. ethers

13. Which of the following shows electron withdrawing groups?

a. phenyl
b. ethers
c. amines
d. alkyl groups

14. Which of the following shows electron donating group?

a. amides
b. esters
c. ketones
d. amines

15. Which of the following has minimum pKa value or maximum acidic strength?

a. imide
b. sulphonamide
c. N-arylsulfonamide
d. sulfonimide

16. Sigma-bonding electrons, especially those from C-H bonds can be donated in a process known as

a. conjugation 

b. Hyperconjugation
c. polarization
d. depolarization

17. Which of the following has neutral pKa value?

a. Water
b. Ether
c. Amide
d. All of the above

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Pinacol Pinacolone Rearrangement