Systematic Nomenclature

1
Systematic Nomenclature
23.1 Nomenclature of Hydrocarbons 23.2 Nomenclatur
e of the Derivatives of Hydrocarbons 23.3 Nomencl
ature of the Derivatives of Aromatic Hydrocarbons
2
Nomenclature

• Means naming of compounds
• The formal system of nomenclature is proposed by
  International Union of Pure and Applies Chemistry
  (IUPAC)
• Fundamental principleEach different compound
  should have a different name

3
Nomenclature of Hydrocarbons
4
23.1 Nomenclature of Hydrocarbons (SB p.52)
Nomenclature of Hydrocarbons

• 4 groups
• Straight-chain acyclic hydrocarbons
• Branched-chain acyclic hydrocarbons
• Cyclic hydrocarbons
• Aromatic hydrocarbons

5
23.1 Nomenclature of Hydrocarbons (SB p.53)
Straight-Chain Acyclic Hydrocarbons
1. The naming of organic compounds is based on
the parent hydrocarbon they derived from
6
23.1 Nomenclature of Hydrocarbons (SB p.53)
Straight-Chain Acyclic Hydrocarbons
2. (a) The suffix -ane is used for
saturated hydrocarbons
7
23.1 Nomenclature of Hydrocarbons (SB p.53)
Straight-Chain Acyclic Hydrocarbons
(b) The suffix -ene is used for unsaturated
hydrocarbons with a double bond e.g. CH2
CH2 ethene CH3CH CH2 propene
8
23.1 Nomenclature of Hydrocarbons (SB p.53)
Straight-Chain Acyclic Hydrocarbons
(c) The suffix -yne is used for unsaturated
hydrocarbons with a triple bond e.g. CH ?
CH ethyne CH3CH ? CH propyne
9
23.1 Nomenclature of Hydrocarbons (SB p.54)
Straight-Chain Acyclic Hydrocarbons
3. The lowest possible number is assigned to the
carbon atoms of the multiple bond
The number is written before the suffix to
indicate the position of the carbon atom of the
multiple bond e.g. CH3CH2CH CH2 but-1-ene
(not
but-3-ene) CH3C ? CCH2CH3 pent-2-yne
(not pent-3-yne)
10
23.1 Nomenclature of Hydrocarbons (SB p.54)
Straight-Chain Acyclic Hydrocarbons

• If a compound contains more than one double or
  triple bond, the prefixes like di-, tri-, are
  used to indicate its number of occurrence
• An a is added to the corresponding stem name
• e.g. CH3CH2CH CHCH CH2
  hexa-1,3-diene

11
23.1 Nomenclature of Hydrocarbons (SB p.54)
Straight-Chain Acyclic Hydrocarbons
5. The geometrical isomers of an alkene are
specified by the word of cis- or trans-
before their names e.g.
12
23.1 Nomenclature of Hydrocarbons (SB p.54)
Branched-Chain Acyclic Hydrocarbons

• Selecting and naming the parent hydrocarbon
• (a) For saturated hydrocarbons, the longest
  possible straight chain is the parent chain, the
  remaining are treated as branched chains

13
23.1 Nomenclature of Hydrocarbons (SB p.54)
Branched-Chain Acyclic Hydrocarbons
e.g.
14
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons
(b) For unsaturated hydrocarbons, the longest
possible straight chain which contains the
maximum number of multiple bonds is chosen as the
parent chain
15
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons
(c) The parent hydrocarbon is named as described
in the naming of straight-chain acyclic
hydrocarbons
16
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons

• Naming branched chains
• (a) The number of carbon atoms in a branched
  chain is indicated by the stem names

17
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons

• The suffix -yl is added to the corresponding
  stem names for branched chains containing only
  single bonds
• e.g. CH3 ? Methyl
• CH3CH2 ? Ethyl
• CH3CH2CH2 ? Propyl

18
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons

• Numbering carbon atoms in the parent hydrocarbon
• (a) For saturated hydrocarbons, the parent
  hydrocarbon is numbered beginning with the end
  of the chain nearer the branched chain

19
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons
e.g.
20
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons
e.g.
21
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons

• For unsaturated hydrocarbons, the parent
  hydrocarbon is numbered so as to include both
  carbon atoms of the double or triple bond
• The numbering begins with the end of the chain
  neared the double or triple bond

22
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons
e.g.
23
23.1 Nomenclature of Hydrocarbons (SB p.55)
Branched-Chain Acyclic Hydrocarbons
e.g.
24
23.1 Nomenclature of Hydrocarbons (SB p.56)
Branched-Chain Acyclic Hydrocarbons

• Use the numbers to designate the position of the
  branched chains
• The parent name is placed last, and the branched
  chain, preceded by the number designating its
  position on the parent chain, is placed first

25
23.1 Nomenclature of Hydrocarbons (SB p.56)
Branched-Chain Acyclic Hydrocarbons
e.g.
26
23.1 Nomenclature of Hydrocarbons (SB p.56)
Branched-Chain Acyclic Hydrocarbons

• When two or more branched chains are present, a
  number corresponding to its position on the
  parent hydrocarbon is given to each branched
  chain so as to give the lowest possible numbers
  to the branched chains
• The branched chains are listed alphabetically
  (i.e. ethyl before methyl)
• Multiplying prefixes such as di and tri are
  ignored when deciding the alphabetical order

27
23.1 Nomenclature of Hydrocarbons (SB p.56)
Branched-Chain Acyclic Hydrocarbons
e.g.
28
23.1 Nomenclature of Hydrocarbons (SB p.56)
Branched-Chain Acyclic Hydrocarbons
e.g.
29
23.1 Nomenclature of Hydrocarbons (SB p.56)
Branched-Chain Acyclic Hydrocarbons
6. When two branched chains are present on the
same carbon atom, use that number twice
30
23.1 Nomenclature of Hydrocarbons (SB p.57)
Branched-Chain Acyclic Hydrocarbons

• When two or more branched chains are identical,
  indicate this by the use of the prefixes di,
  tri, tetra etc.
• Commas are used to separate numbers from each
  other

31
23.1 Nomenclature of Hydrocarbons (SB p.57)
Branched-Chain Acyclic Hydrocarbons
e.g.
32
23.1 Nomenclature of Hydrocarbons (SB p.57)
Cyclic Hydrocarbons
Simple cyclic hydrocarbons are named by adding
the prefix cyclo- to the names of their
corresponding acyclic counterparts
33
23.1 Nomenclature of Hydrocarbons (SB p.57)
Cyclic Hydrocarbons
e.g.
34
23.1 Nomenclature of Hydrocarbons (SB p.57)
Aromatic Hydrocarbons
1. Some aromatic hydrocarbons have specific names
35
23.1 Nomenclature of Hydrocarbons (SB p.57)
Aromatic Hydrocarbons

• For substituted benzenes, the benzene ring is
  numbered so as to give the lowest possible
  numbers to the substituents
• When more than two substituents are present and
  the substituents are different, list them in
  alphabetical order
• The names of the substituents together with the
  numbers indicating their positions are added
  before the word benzene

36
23.1 Nomenclature of Hydrocarbons (SB p.57)
Aromatic Hydrocarbons
e.g.
37
23.1 Nomenclature of Hydrocarbons (SB p.57)
Aromatic Hydrocarbons
e.g.
38
23.1 Nomenclature of Hydrocarbons (SB p.57)
39
Nomenclature of the Derivatives of Hydrocarbons
40
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.59)
Nomenclature of Compounds with One Type of
Functional Group

• 2 groups
• Compounds with functional groups that must be
  designated as prefixes
• Compounds with functional groups that may be
  expressed as prefixes or suffixes

41
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.60)
Compounds with Functional Groups that Must be
Designated as Prefixes
42
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.60)
Compounds with Functional Groups that Must be
Designated as Prefixes

• Whether the carbon chains are saturated or
  unsaturated, straight or branched, they are named
  and numbered in the usual way
• Numbers are assigned to functional groups in the
  same way as the alkyl substituents

43
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.60)
Compounds with Functional Groups that Must be
Designated as Prefixes
e.g.
44
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.60)
Compounds with Functional Groups that Must be
Designated as Prefixes

• When the parent chain has both alkyl groups and
  other substituents, the chain is numbered from
  the end nearest to the first substituent,
  regardless of what substituents are
• All the prefixes are then arranged in
  alphabetical order

45
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.60)
Compounds with Functional Groups that Must be
Designated as Prefixes
e.g.
46
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.61)
Compounds with Functional Groups that Must be
Designated as Prefixes
3. When two or more substituents are identical,
indicate this by the use of the prefixes di,
tri, tetra etc.
47
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.61)
Compounds with Functional Groups that Must be
Designated as Prefixes
e.g.
48
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.61)
Compounds with Functional Groups that May be
Designated as Prefixes or Suffixes
Suffix of compounds with one functional group
which may be expressed as prefixes or suffixes
49
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.61)
Compounds with Functional Groups that May be
Designated as Prefixes or Suffixes
Suffix of compounds with one functional group
which may be expressed as prefixes or suffixes
50
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.61)
Compounds with Functional Groups that May be
Designated as Prefixes or Suffixes
Suffix of compounds with one functional group
which may be expressed as prefixes or suffixes
51
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.61)
Compounds with Functional Groups that May be
Designated as Prefixes or Suffixes
1. Principal functional group is the functional
group expressed as a suffix and has priority over
unsaturated centres 2. Parent carbon chain is
chosen to include the longest possible carbon
chain and maximum number of principal functional
groups
52
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.61)
Compounds with Functional Groups that May be
Designated as Prefixes or Suffixes

• 3. The carbon chain is numbered to give the
  principal functional group the lower number
• The position of the principal functional group is
  indicated by using this number
• The positions of other substituents are
  indicated by using the numbers corresponding to
  their positions along the parent carbon chain

53
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.62)
Compounds with Functional Groups that May be
Designated as Prefixes or Suffixes
(a) Alcohols (ending -ol)
54
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.62)
(a) Alcohols (ending -ol)
55
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.62)
(b) Aldehydes (ending -al) and ketones (ending
-one)
56
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.62)
(b) Aldehydes (ending -al) and ketones (ending
-one)
e.g.
57
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.63)
(c) Carboxylic acids (ending -oic acid)
58
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.63)
(d) Acyl chlorides (ending -oyl chloride)
59
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.63)
(e) Amides (ending -amide)
Alkyl groups on the nitrogen atom of amides are
named as substituents and the named substituent
is preceded by N- or N, N-
60
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.63)
(e) Amides (ending -amide)
e.g.
61
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.63)
(f) Esters (ending -oate)
The name of an ester is derived from the names of
the alcohol (with the ending yl) and the
carboxylic acid (with the ending -oate) forming
the ester The portion of the name derived from
the alcohol comes first, and then the carboxylic
acid
62
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.63)
(f) Esters (ending -oate)
e.g.
63
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.64)
64
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.65)
Nomenclature of Compounds with More Than One Type
of Functional Group
1. Only one of the functional groups can be
designated as the ending of the name. This
functional group is the principal functional group
65
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.65)
Prefixes and suffixes for some common functional
groups (in decreasing order of priority)
66
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.65)
Prefixes and suffixes for some common functional
groups (in decreasing order of priority)
67
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.66)
Nomenclature of Compounds with More Than One Type
of Functional Group

• The principal functional group has priority in
  the selection of the longest possible carbon
  chain and the choice of the lowest number
• All other groups are designated as prefixes and
  listed in alphabetical order

68
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.66)
(a)
69
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.66)
(a)
70
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.66)
(a)
Substituents named as prefixes in alphabetical
order ?Cl (4-chloro)
?CH3 (4-methyl)
The name of the compound is 4-chloro-4-methylpent
anal.
71
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.66)
(b)
72
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.67)
(b)
73
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.67)
(b)
Substituents named as prefixes in alphabetical
order ?Br (2-bromo)
?CH3 (3-methyl)
The name of the compound is 2-bromo-3-methylbut-2
-enoic acid.
74
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.67)
(c)
75
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.67)
(c)
76
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.67)
(c)
Substituents named as prefixes in alphabetical
order ?Cl (3-chloro)
?I (2-iodo)
The name of the compound is 3-chloro-2-iodobutana
mide.
77
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.67)
(d)
78
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.67)
(d)
79
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.67)
(d)
Substituents named as prefixes in alphabetical
order ?Cl (3,4-dichloro)
?OH (5-hydroxy) ?CH3 (4-methyl)
The name of the compound is 3,4-dichloro-5-hydrox
y-4-methylpentan-2-one.
80
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.68)
(e)
81
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.68)
(e)
82
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.68)
(e)
The name of the compound is 4-amino-2-phenylhexan
al.
83
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.69)
84
Nomenclature of the Derivatives of Aromatic
Hydrocarbons
85
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.70)
Monosubstituted Aromatic Hydrocarbons
1. For certain monosubstituted aromatic
hydrocarbons, they are named by adding the names
of the substituents as prefixes to the name of
the aromatic hydrocarbon
86
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.70)
Monosubstituted Aromatic Hydrocarbons
e.g.
87
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.70)
Monosubstituted Aromatic Hydrocarbons
2. For other monosubstituted aromatic
hydrocarbons, the substituent and the benzene
ring taken together may form a new parent name
88
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.70)
Monosubstituted Aromatic Hydrocarbons
e.g.
89
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.70)
Monosubstituted Aromatic Hydrocarbons
e.g.
90
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.71)
Polysubstituted Aromatic Hydrocarbons

• When two or more substituents are identical,
  indicate this by the use of the prefixes di-,
  tri-, tetra- etc.
• The benzene ring is numbered so as to give the
  lowest possible numbers to the substituents

91
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.71)
Polysubstituted Aromatic Hydrocarbons
e.g.
92
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.71)
Polysubstituted Aromatic Hydrocarbons
2. When the substituents are different, they are
listed in alphabetical order
93
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.71)
Polysubstituted Aromatic Hydrocarbons

• When a substituent is one that when taken
  together with the benzene ring gives a new parent
  name
• ? that substituent is assumed to be in position
  1 and the new parent name is used

94
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.71)
Polysubstituted Aromatic Hydrocarbons
e.g.
95
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.72)
96
The END
97
23.1 Nomenclature of Hydrocarbons (SB p.58)
Example 23-1
Give the structural formula for each of the
following compounds (a) 2-Methylbutane (b)
2,2,3-Trimethylpentane (c) 3-Ethyl-2-methylhexane
Answer
98
23.1 Nomenclature of Hydrocarbons (SB p.58)
Example 23-1
Give the structural formula for each of the
following compounds (d) 3-Methylbut-1-ene (e)
2-Propylpent-1-ene
Answer
99
23.1 Nomenclature of Hydrocarbons (SB p.58)
Back
Example 23-1
Give the structural formula for each of the
following compounds (f) 3-Ethylhex-1-yne (g)
1,2-Dimethylbenzene (h) Cyclopentane
Answer
100
23.1 Nomenclature of Hydrocarbons (SB p.59)
Check Point 23-1

• Give the IUPAC name for each of the following
  compounds
• (b)

Answer

• Dimethylpropane
• 2,4-Dimethylhex-2-ene

101
23.1 Nomenclature of Hydrocarbons (SB p.59)
Check Point 23-1
Give the IUPAC name for each of the following
compounds (c) (d)
Answer

• 3-Methylpent-1-yne
• 1-Methylcyclohexene

102
23.1 Nomenclature of Hydrocarbons (SB p.59)
Back
Check Point 23-1
Give the IUPAC name for each of the following
compounds (e)
(e) Ethylbenzene
Answer
103
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.64)
Example 23-2A
Give the structural formula for each of the
following compounds (a) 2-Methylhexane (b)
4-Methylheptan-2-ol
Answer
104
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.64)
Example 23-2A
Give the structural formula for each of the
following compounds (c) Pentan-2-one (d)
5-Methylhexanoic acid
Answer
105
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.64)
Back
Example 23-2A
Give the structural formula for each of the
following compounds (e) Methyl
2,2-dimethylpentanoate (f) N-ethyl-N-propylethanam
ide
Answer
106
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.64)
Check Point 23-2A
Give the IUPAC name for each of the following
compounds (a) (b)

• 3,4-Dimethylpentanoic acid
• Pentan-2-ol

Answer
107
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.64)
Check Point 23-2A
Back
Give the IUPAC name for each of the following
compounds (c) (d)
(c) 3,4-Dimethylhexanal (d) N,N-Dimethylpropanamid
e
Answer
108
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.69)
Example 23-2B
Give the structural formula for each of the
following compounds (a) 3-Oxobutanoic acid (b)
5-Hydroxypentanal
Answer
109
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.69)
Back
Example 23-2B
Give the structural formula for each of the
following compounds (c) 2-Hydroxy-4-oxohexanal (d
) 1,8-Dihydroxyoctan-3-one
Answer
110
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.69)
Check Point 23-2B
Give the IUPAC name for each of the following
compounds (a) (b)

• 3-Chlorobutanone
• 1-Ethoxyethanol

Answer
111
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.69)
Back
Check Point 23-2B
Give the IUPAC name for each of the following
compounds (c) (d)
(c) 2-Amino-3-hydroxypentanoic acid (d) 4-Hydroxy-
2-methylpentanamide
Answer
112
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.69)
Let's Think 1
A student has given the wrong names for the
following organic compounds. Try to guess the
structural formulae and the correct names for
these compounds (a) 3-Hydroxy-3-ethylbutanoic
acid (b) 2-Chloro-3-cyano-1-methylpropane (c)
Propoxyethane
Answer
113
23.2 Nomenclature of the Derivatives of
Hydrocarbons (SB p.69)
Back
114
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.72)
Example 23-3
Give the structural formula for each of the
following compounds (a) 1,4-Dichlorobenzene (b)
3-Nitrobenzoic acid
Answer
115
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.72)
Back
Example 23-3
Give the structural formula for each of the
following compounds (c) 4-Bromotoluene (d)
3,5-Dinitrophenol
Answer
116
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.72)
Check Point 23-3
Give the IUPAC name for each of the following
compounds (a)
(b)
Answer
(a) 2-Bromo-1,4-dichlorobenzene (b) 5-Bromo-2-chlo
robenzoic acid
117
23.3 Nomenclature of the Derivatives of Aromatic
Hydrocarbons (SB p.72)
Back
Check Point 23-3
Give the IUPAC name for each of the following
compounds (c)
(d)
Answer
(c) 2,4-Difluorobenzenesulphonic
acid (d) 4-Hydroxybenzoic acid