isomerism short note for b.pharmacy

           Isomerism in organic compound 

Different compound having the same molecular formula are called isomers (greek , isos, equal , moros , part ) and this phenomeran is know as isomerism …

Types of isomerism

1  = structural ( comstitutioral )

2 =

                           Structural isomerism

When the isomerism differ due to the arrangement when the isomers or groups within the molecule , these are knows as structural isomerism thus the structural isomers have the same molecular formula , but posses diffirent structural formulas it is of five types …………

1.            Chain isomerism

2.            Position isomerism

3.            Functional isomerism

4.            Metameries

5.            Tautomeris

1. Chain isomerism…

Compound having the same molecular formula , but different arragment of carbon chain within the molecule are called chain isomers and this phenomena is called chain isomerism ……

FOR EXAMPLE …. C₄H₁₀    has two chain isomers

CH_3-CH_2-CH_2-CH₃    =  BUTANE

2. Positional isomerism …

Compound having the same molecular formula but different only in the position on functional group or double / triple bond are called position isomers and this phenomena called as position isomerism …..

FOR EXAMPLE ….

 Propane and propane 2. 0 / are positional isomers ….

CH₃-CH=CH-CH₃                                      CH₃-CH- CH₃

But-2 ene                                  OH ( propane -2-01.

3. functional isomerism…

   Compound having the same molecular formula but differ functional group are called functional isomers and this phenomena called functional isomerism..

FUR EXAPLE … actone and properal dydred are functional isomersm because both have same molecular formula …

CH₃-CH_2­-CHO

Propanaldehyde or propanal

4. metamerism

Compound have same molecular formula differ  no. of carbon atom on either side of functional group are called metemers and this phenomena called meta merism ..

This type of isomerism is possible in those functional groups which are always present in the middle of chain , as ketonic group , ether secondary and tetra amines  etc….

FOR EXAMPLE …. Diethyl ether , methyl an – propyal & methyl, isopropyl ether ( C₄ H₁₀O)..

6.TAUTOMERISM..

 Tautomerism occurs due to 1, 3 migration of hydrogen atom  from one polyvalent atom to the other within the same molecular ..

These forms ( isomerism ) are called tautumersm . the two forms are readily inter – convertible and exist in dynamic equilibrium with each other …

 FOR EXAMPLE …     keto- enot tautomerism amido- amidol tautomerism