NOMENCLATURE IN ORGANIC CHEMISTRY

Company

LOGO
Natural Sciences Department

Module 3:
NOMENCLATURE IN ORGANIC
CHEMISTRY
Company
Lecturer: Nguyen
Van Tien

LOGO

Chapter 1: General Organic Chemistry

Module 3: Nomenclature


Company

LOGO

Content

I. Naming Hydrocarbon.
II. Naming other organic compounds
III. Drawing Structural Formulas


Company

Naming

LOGO

IUPAC: each name consists of 3 parts
prefix
 indicates position, number, and type of branches
 indicates position, number, and type of each functional
group

parent
 indicates the length of the longest carbon chain or ring

suffix
 indicates the type of hydrocarbon


ane, ene, yne

 certain functional groups
Chapter 1: General Organic Chemistry

Module 3: Nomenclature


Company

LOGO

NAMING HYDROCARBON

Aliphatic hydrocarbons
ALKANES (CnH2n+2)
ALKENES (CnH2n)
ALKYNES (CnH2n-2)
Aromatic hydrocarbons: (CnH2n-6)

Chapter 1: General Organic Chemistry

Module 3: Nomenclature


Company

LOGO

Naming Alkanes

1) Find the longest continuous carbon chain
2) Number the chain from end closest to a branch
3) Name branches as alkyl groups

locate each branch by preceding its name with
the carbon number on the chain
4) List branches alphabetically

do not count n-, sec-, t-, count iso
5) Use prefix if more than one of same group present


di, tri, tetra, penta, hexa

do not count in alphabetizing
Chapter 1: General Organic Chemistry

Module 3: Nomenclature


Company

Alkyl Groups

LOGO
H
H C
H

C H 3 -, M E T H Y L

H H
H C C
H H

C H 3 C H 2 -, E T H Y L

H H H
H C C C
H H H

C H 3 C H 2 C H 2 -, P R O P Y L

H CH3
H C C
H H

( C H 3 ) 2 C H -, IS O P R O P Y L

Chapter 1: General Organic Chemistry

Module 3: Nomenclature

6


Company

LOGO

More Alkyl Groups
H H H H
H C C C C
H H H H

C H 3 C H 2 C H 2 C H 2 -, n-BU TYL

H H CH3
H C C C
H H H

C H 3 C H 2 (C H 3 )C H-, sec-B UTYL

H
H C
H

(C H 3 ) 2 C HC H 2 -, IS OB U TYL

CH3 H
C
C
H
H

CH3
H3C C
CH3
Chapter 1: General Organic Chemistry

(C H 3 ) 3 C-, tert- BUTYL

Module 3: Nomenclature


Company

LOGO

Example – Name the alkane
CH3CHCH2CHCH3
CH3

CH3

1) find the longest continuous C chain and
use it to determine the base name

CH3CHCH2CHCH3
CH3

CH3

since the longest chain has 5 C
the base name is pentane
Chapter 1: General Organic Chemistry

Module 3: Nomenclature


Company

LOGO

Example – Name the alkane
CH3CHCH2CHCH3
CH3

CH3

2) identify the substituent branches

CH3CHCH2CHCH3
CH3

CH3

there are 2 substituents
both are 1 C chains, called methyl
Chapter 1: General Organic Chemistry

Module 3: Nomenclature


Company

LOGO

Example – Name the alkane

3) number the chain from the end closest to a
substituent branch


if first substituents equidistant from end, go to next
substituent in

then assign numbers to each substituent based
on the number of the main chain C it’s attached to
1

2

3

4

5

CH3CHCH2CHCH3

both substituents are
equidistant from the end

CH3
2

Chapter 1: General Organic Chemistry

CH3
4

Module 3: Nomenclature


Company

LOGO

Example – Name the alkane

4) write the name in the following order

1)
2)

3)
4)

substituent number of first alphabetical substituent followed by dash
substituent name of first alphabetical substituent followed by dash
 if it’s the last substituent listed, no dash
 use prefixes to indicate multiple identical substituents
repeat for other substituents alphabetically
name of main chain

CH3CHCH2CHCH3
CH3
2

CH3

2,4 –dimethylpentane

4

Chapter 1: General Organic Chemistry

Module 3: Nomenclature


Company

LOGO

Practice – Name the Following
methyl
CH3
CH3 CHCHCH2 CH3
1

2

3

4

5

CH2 CH3

ethyl

there are 2 substituents

find
the the
longest
continuous
Cclosest
chaintoand
number
chain

from the endbranches
a use
identify
the substituent
branch
itsubstituent
to determine
the base name
Chapter 1: General Organic Chemistry

Module 3: Nomenclature

12


Company

LOGO

Practice – Name the Following
methyl
CH3
CH3 CHCHCH2 CH3
1

2

3

4

5

CH2 CH3

ethyl

3-ethyl-2-methylpentane


Company

LOGO

Drawing Structural Formulas
4-ethyl-2-methylhexane

 draw and number the
base chain carbon
skeleton
 add the carbon
skeletons of each
substituent on the
appropriate main chain
C
 add in required H’s

C C C C C C
1 2 3 4 5 6

C C C C C C
C

C C

CH3 CH CH2 CH CH2 CH3
CH3

H2C CH3


Company

LOGO

Practice – Draw the structural formula
4-isopropyl-2-methylheptane

draw and number the base chain carbon skeleton
add the carbon skeletons of each substituent on the
add chain
in required
H’s
appropriate main
C