Nomenclature of Organic Compounds 3

IUPAC system and IUPAC rules of naming ethers

Common names of ethers follow after the names of alkyl / aryl groups written as separate words in alphabetical order. The word ether is added at the end.

In case of simple ethers, the prefix di is attached before the name of the alkyl group.


C2H5 - O - C2H5 is Diethyl ether

C6H5 - O - C6H5 is Diphenyl ether

C2H5 - O - C6H5 is Dthyl phenyl ether.

According to the IUPAC nomenclature ethers are regarded as hydrocarbon derivatives in which a hydrogen atom is replaced by an alkoxy group - OR, the larger group (R) being chosen as the parent hydrocarbon. Ethers are named as alkoxyalkenes. The larger alkyl group forms the part of parent chain while lower alkyl group constitutes the alkoxy radical.


The numbering of the parent chain is done so that the carbon atom linked to the -O-atom gets the lowest number.

IUPAC system and IUPAC rules of naming of halogen derivative of carboxylic acid

Functional class name = acyl or acid halide

Substituent suffix = -oyl halide

Acyl or acid halides are derivatives of carboxylic acids.

The root name is based on the longest chain including the carbonyl group of the acyl group.

Since the acyl group is at the end of the chain, the C=O carbon must be C1.

The acyl halide suffix is appended after the hydrocarbon suffix minus the "e" : e.g. -ane + -oyl halide = -anoyl halide etc.

The most common halide encountered is the chloride, hence acyl or acid chlorides, e.g. ethanoyl chloride

Functional group is an acyl halide therefore suffix = -oyl chloride

Hydrocarbon structure is an alkane therefore -an-

The longest continuous chain is C2 therefore root =eth


ethanoyl chloride


Functional group is an acyl halide therefore suffix = -oyl chloride

Hydrocarbon structure is an alkane therefore -an-

The longest continuous chain is C4 therefore root =but



butanoyl chloride


Functional group is an acyl halide therefore suffix = -oyl chloride

Hydrocarbon structure is an alkane therefore -an-

The longest continuous chain is C3 therefore root =prop

The branch is a C1 alkyl group i.e. a methyl group

The functional groups requires numbering from theright as drawn, the substituent locant is 2-


2-methylpropanoyl chloride

IUPAC system and IUPAC rules of naming of esters

Esters are a group of organic compounds with a general formula R1CO2R2 (where R1 and R2 are alkyl groups) that are formed, along with water, by the reaction of acids and alcohols. Natural occurring esters of organic acids in fruits and flowers give them their distinctive odors. It also also used for food aroma and taste, perfumes, synthetic fibres, and solvents.

How to name esters,


  1. Identify the alkyl group that is attached to the oxygen atom
  2. Number according to the end closest to the -CO- group regardless of where alkyl substituents are.
  3. Determine the alkane that links the carbon atoms together. If there is a separation of a continuous link of carbon atoms due to the oxygen atom, individually name the two alkanes before and after the oxygen atom. The longer structural alkane is the one that should contain the carbonyl atom.
  4. The format is as follows: (alkane further from carbonyl) (alkane closest to carbony)(parent chain)
  5. Change the parent chain -e ending and replace it with an -oate.



    CH3COOC7H14CH3     octyl ethanoate

IUPAC system and IUPAC rules of naming of amines

Aliphatic amines are named by adding the suffix amine to the name of the alkyl group and it is written as one word. E.g., C2H5NH2 is Ethylamine. When two or more alkyl groups in secondary or tertiary amines are some, the prefix di or tri is used. For e.g., (C2H5)2 NH is diethylamine.

In the case of mixed amines, the names of alkyl groups are arranged in alphabetical order. The amines are named as N-substituted derivatives of the largest group of primary amine.


(C2H5)2NCH2CH2CH2CH3 - N, N - diethyl butylamine

In the IUPAC system the amines are considered to be amino derivatives of corresponding alkanes. Therefore, they are called aminoalkanes or alkanamines. Their  names are obtained either by adding a prefix amino before the name of parent alkane or by replacing 'e' from the name of the parent alkene with suffix amine.


In case of diamines the ending e of the hydrocarbon name is retained and the suffix diamine is added H2N-(CH2)5-NH2 is 1,5 - Pentanediamine.

When additional functional groups such as -OH or double bond are present in an amine, the prevailing priority order for nomenclature is observed.

H2N CH2 CH2 OH                 2 - amino ethanol

H2N CH2 CH = CH2               2 - propen1 – amine


IUPAC system and IUPAC rules of naming of nitriles

Nitriles contain a carbon - nitrogen triple bond (R-CºN or R-CN). They are indirectly related to amides (by the loss of H2O from a primary amide), and react chemically similar to carboxylic acids and their derivatives. It should be noted that H-CºN is not truly a nitrile and is named hydrogen cyanide.

When a nitrile group is the highest priority functional group present in the molecule, it is named as an alkanenitrile (alkenenitrile, alkynenitrile, ...). As  the -CºN must occur at the end of a chain of carbon atoms, the carbon of the nitrile will be carbon 1 in the numbering scheme. Other functional groups are located by this numbering scheme. Since the nitrile group is always at carbon number 1, there is no need to indicate its' location.


Examples naming more complex nitriles:

Common names of organic compounds

Common nomenclature

In the common system, cyanides are named by any of the following methods:

(i) By using suffix cyanide after the name of alkyl and aryl group.


(ii) By adding the suffix o-nitrile in place of ic - acid in the common name of the corresponding acid produced by the hydrolysis of the cyanide compound.

For e.g., CH3 CN on hydrolysis gives CH3 COOH i.e., acetic acid.

So the common name of the compound is methyl cyanide or Acetonitrile as derived from acetic acid.