• These names were given after the source from which the organic compounds were first isolated.

• Example:

1. Acetic Acid got its name from Acetum present in vinegar.

2. Wood Spirit (Methyl Alcohol) got its name because it was first obtained by destructive distillation of wood.

A BOTTLE OF ACETIC ACID A.K.A. VINEGAR

• IUPAC stands for International Union of Pure And Applied Chemistry. They have given certain rules to systematize the nomenclature of organic compounds. The names based upon these rules are called IUPAC names.

• The IUPAC name of any organic compound can be derived by using the rules as described in the following slides.

IUPAC LOGO

1. Identify the number of carbon atoms in compound

• A compound containing one carbon atom will be named as methane. Similarly

• Two carbon atom as Ethane

• Three carbon atom as Propane

• Four carbon atom as Butane

• Five carbon atom as Pentane

and so on…

2. The functional group present in the organic compound is indicated either by a prefix or suffix

• Prefixes and suffixes of common functional groups are:

S. No. Functional Group Prefix Suffix

1. Chlorine Chloro -

2. Bromine Bromo -

3. Alcohol - ol

4. Aldehyde - al

5. Ketone - one

6. Carboxylic Acid - oic acid

7. Double Bond (Alkenes) - ene

8. Triple Bond (Alkynes) - yne

3. If a suffix is to be added, the final ‘e’ from the name of the carbon chain is deleted.

4. If the carbon chain is unsaturated, the final ‘ane’ from the name of the carbon chain is replaced by either ‘ene’ if the carbon chain contains one double bond or by ‘yne’ if the carbon chain contains a triple bond.

5. The position of the functional group on the carbon chain is given by the lowest possible numerical prefix, i.e., 1,2,3,4…, etc.

• The removal of one hydrogen atom from the molecule of an alkane gives an alkyl

group. Thus, alkyl group has the general formula 𝐶𝑛𝐻2𝑛+1.These are often represented by the letter R. Their names are derived by replacing the terminal ‘ane’ of the corresponding alkane by the suffix ‘yl’, i.e., Alkane – ane + yl = Alkyl.

For example,

𝐶𝐻3- 𝐶𝐻3𝐶𝐻2- 𝐶𝐻3𝐶𝐻2𝐶𝐻2-

Methyl Ethyl n-Propyl

The nomenclature of some important classes of organic compounds is discussed on the coming slides……..

……So be prepared

•General formula : 𝐶𝑛𝐻2𝑛 .

• Functional group : 𝐶 = 𝐶(double bond)

• Suffix : ene

•Names. Replace the terminal ‘ane’ from the name of the corresponding alkane by suffix ‘ene’.

•General formula : 𝐶𝑛𝐻2𝑛−2.

• Functional group : 𝐶 ≡ 𝐶 (triple bond)

• Suffix : yne

•Names. Replace the terminal ‘ane’ from the name of the corresponding alkane by suffix ‘yne’.

•General formula : 𝐶𝑛𝐻2𝑛+1𝑋 (where X=F, Cl, Br or I)

• Functional group : F, Cl, Br, I

• Prefix : Fluoro, Chloro, Bromo, Iodo

•Names. Add the prefix halo, i.e., fluoro, chloro, bromo or iodo to the name of the corresponding alkane.

•General formula : 𝐶𝑛𝐻2𝑛+1𝑂𝐻.

• Functional group : 𝑂𝐻 (hydoxyl)

• Suffix : ol

•Names. Replace the terminal ‘e’ from the name of the corresponding alkane by suffix ‘ol’.

•General formula : 𝐶𝑛𝐻2𝑛+1𝐶𝐻𝑂• Functional group : 𝑂

∥−𝐶 − 𝐻 (aldehyde)

• Suffix : al

•Names. Replace the terminal ‘e’ from the name of the corresponding alkane by suffix ‘al’.

•General formula : 𝐶𝑛𝐻2𝑛+1𝐶𝑂𝐶2ṅ+1• Functional group : 𝑂

∥−𝐶 − (ketone)

• Suffix : one

•Names. Replace the terminal ‘e’ from the name of the corresponding alkane by suffix ‘one’.

•General formula : 𝐶𝑛𝐻2𝑛+1𝐶𝑂𝑂𝐻• Functional group : 𝑂

∥−𝐶 − 𝑂𝐻 (carboxyl)

• Suffix : oic acid

•Names. Replace the terminal ‘e’ from the name of the corresponding alkane by suffix ‘oic acid’.