L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
NOMENCLATURE OF ORGANIC MOLECULES 系統命名法
Chapter 26:
I.
Chpt:26 p.1
Introduction
The IUPAC (International Union of Pure and Applied Chemistry) 國際純化學及應用化學學
會體系 is the most popular system whose rules of chemical nomenclature are widely applied
by chemist throughout the world.
II.
IUPAC Nomenclature of Acyclic Hydrocarbons 非環狀碳氫化合物
(A)
Saturated Hydrocarbons — alkanes with general formula CnH2n+2
Name =
first part.
+
second part
( indicate the no. of carbon atoms)
( suffix 詞尾– ane )
(1)
(2)
Straight chain alkanes
Examples
CH4 methane 甲烷 C5H12
C2H6 ethane 乙烷 C6H14
C3H8 propane
C7H16
C4H10 butane
C8H18
pentane
hexane
heptane 庚烷
octane 辛烷
C9H20 nonane 壬烷
C10H22 decane 癸烷
C11H24 undecane
C12H26 dodecane
Branched chain alkanes
alkyl group (CnH2n+1-) :
obtained by removing a hydrogen atom from an alkane.
e.g.
CH3— methyl
C2H5— ethyl
C3H7— propyl
C4H9— butyl
Naming method :
<1>
The longest unbranched parent chain is first established and named after the
corresponding alkanes.
The parent chain is numbered to give the substituents 取代基 the“lowest” possible
number.
Each substituents is specified its name and position number.
<2>
<3>
Examples
CH3
1.
CH3 CH
CH3
CH2 CH2
2.
___________________________
3.
CH3
CH3
CH3
CH3
CH2
CH
CH CH2
CH3 CHCH2 CH
CH3
CH2
CH3
____________________________
CH3
______________________________
CH3
CH2
CH2
4.
CH3
C
H
CH3
CH2 CH2 CH2 CH
CH3
CH CH2 CH3
______________________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
(B)
Chpt:26 p.2
Unsaturated Hydrocarbons — alkenes with general formula CnH2n and
alkynes with general formula CnH2n-2
Examples
C2H4 ethene
C3H6 propene
C2H2 ethyne
C3H4 propyne
Naming method :
<1>
<2>
<3>
Pick the longest chain containing the double or triple bond,
Name it after the corresponding alkane, but change the ending ‘–ane’ to ‘-ene’ for alkenes and
‘-yne’ for alkynes,
Number the parent chain so that the double bond or triple bond
Examples
Alkene
Note
<1>
Alkyne
When a hydrocarbon contains more than one unsaturated centre, the parent chain is chosen to
contain the maximum number of unsaturated groups, even though it may be possible to
designate a longer, but more saturated chain.
Example
CH2 C
CH
CH2 CH3
<2>
CH2
_______________________________
General names of simple unsaturated hydrocarbon (with more than one unsaturated centre)
No. of double bonds No. of triple bonds
2
0
0
2
1
1
2
1
Remark :
General name
alkadiene
alkadiyne
alkenyne
alkadienyne
When both types of unsaturation are present the double bond (ene) is named in front of
the triple bond (yne), as in alkaenyne.
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
<3>
The main chain containing the unsaturated centres is numbered in the following order of
priority to allocate the lowest possible number:
(i)
(ii)
(iii)
Double and triple bonds all taken together;
Double bonds; and
Triple bonds
Examples :
1.
<4>
Chpt:26 p.3
CH3CC-CH2-CH2-CH=CH2
_____________________________
2.
HCC-CH2-CH=CH2
_____________________________
3.
CH3CH=CH-CCH
_____________________________
Geometrical isomerism 幾何異構體 around the double bond is indicated by the prefixes cis- and
trans-.
Cis- 正 : two bulky groups are on the same side of the double bonds
trans- 反 : on the opposite side
Examples
CH3
H
C
1.
CH3
C
H
C
CH3
______________________
2.
H
CH3
C
H
________________________
III.
IUPAC Nomenclature of Compounds with other Functional Groups
(A)
Compounds with single functional group
<1> Those that must be expressed as prefixes 詞頭 only
e.g.
Halogen (Cl, Br, I), nitro (NO2 硝基). nitroso (NO 亞硝基), ether (OCH3 甲烷氧基, OCH2CH3)
In naming the compounds, the prefixes should be arranged among them in alphabetical order,
e.g. bromo between chloro.
Examples
1.
Haologeno-hydrocarbon
Cl
CH3 CH
CH3
CH CH2 CH3
_________________
2.
I
CH3 CH
I
CH
CH3
CH2
__________________
CH CH2 CH2 Br
_____________________
Nirto- compounds:
NO2
CH3 CH
CH2
CH2 CH2 CH3
_____________________
CH CH CH3
NO2
_______________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
3.
Chpt:26 p.4
Ethers
CH3 O
CH3 CH2 O
CH3 CH CH2
CH2 CH3
________________________
CH3 CH2 O
CH2
CH3
__________________________
CH2 CH CH2
CH3 O
________________________
CH2 CH2 CH2 O
CH3
__________________________
<2> Those that may be expressed as prefixes or suffixes (endin8s)
e.g.
acids, esters, acid chlorides, amides, nitriles, aldehydes, ketones and alcohols.
Suffix (endings) for some functional groups:
Group
carboxylic acid 羧酸
ester 酯
acid chloride 酉先氯
amide 酉先胺
aldehyde 醛
ketone 酮
alcohol 醇
General formula
RCO2 H
-CO2 R’
RCOCl
RCONH2
RCHO
RCOR’
ROH
Suffix
-oic acid
-oate
-oyl chloride
-amlde
-al
-one
-ol
Systematic name
alkanoic acid 烷酸
alkyl alkanoate 烷酯
alkanoyl chloride 烷酉先氯
alkanamide 烷酉先胺
alkanal 烷醛
alkanone 烷酮
alkanol 烷醇
Naming method
1.
2.
The principal functional group has the priority over unsaturated centres
The main carbon chain is chosen to include the maximum. number of principal
functional group, and is numbered to give the Lowest possible number to a principal
functional group first, before unsaturation centres are considered.
Examples
1.
Alcohols ( suffix -ol )
CH3
CH3 C
CH3 CH
OH
_____________________
2.
OH OH
CH2 CH2 CH3
CH CH2 CH3
_______________________
CH3CH=CHCH2CH2CH2OH
_______________________
Aldehydes (suffix -al) , and Ketones (suffix —one)
H3 C
CH2 CH
CH3
CH3 CH2 CHO
___________________
O
CH3 C
CH3
CH CH2 CH3
___________________
CH2 CHO
HO
______________________
O
CH3 O
CH3 C
CH C
CH3
______________________
CH2 CH2 CH2 CHO
________________________
O
CH3 O
CH3 C
CH C
CH3
_______________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
3.
Carboxylic acid
(suffix —oic acid)
O
CH3 CH2 C
HO
OH
__________________
4.
Acid chlorides,
Chpt:26 p.5
O
O
C
CH2 CH2 C
CH3 O
OH
CH3 CH
_______________________
C
____________________
Amides, and Nitriles
Propanane
Propanoic acid
_________________________
_________________________
_________________________
_________________________
_________________________
_________________________
5.
Esters
Name = 2 separate words
:
1st word
from alcohol
_______________________________
OH
2nd word
from acid
__________________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
Chpt:26 p.6
(B)
Nomenclature of Polyfunctional Compounds
The following rules should be applied when naming polyfunctional 多項官能基 compounds.
1.
Only one of the functional groups can be designated as the suffix or ending of the name. All
other functional groups have to be indicated by prefixes which will be named in alphabetical
order.
Functional group which is higher in the list of order of priority becomes the principal functional
group and would be designated at the end of the name.
2.
3.
The principal functional group has priority in the selection of the longest chain, and the choice
of lowest number
When the principal group is expressed at the end of the whole name and has priority for the
choice of lowest number; all other groups are designated as prefixes and listed in -alphabetical
order.
Example 1
O
HO
CH2 CH
CH3
CH
C
C
CH3
Br
Naming procedure
(i)
Functional groups :
___________________________________________________
(ii)
Principal functional group : _____________________________________________
(iii)
Principal chain including principal group:
(iv)
Prefixes in alphabetical order :
_________________________________
_______________________________________
The name should be : __________________________________________________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
Chpt:26 p.7
Example 2
Naming procedure
(i)
Functional groups : ______________________________________________________
(ii)
Principal functional group : ______________________________________________
(iii)
Principal chain including principal group:
(iv)
Prefixes in alphabetical order : _____________________________________________
__________________________________
The name should be ________________________________________________________________
Example 3
_________________________
______________________________
_________________________
______________________________
Note : Naming of amines.
<1> Amine is named as a suffix.
___________________________
_______________________________
<2> Amine group is named as a prefix amino
______________________
________________________
_______________________
___________________________
___________________________
___________________________
___________________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
IV.
Nomenclature of Cyclic Compounds 環狀化合物
(A)
Nomenclature of Cyclic Saturated Hydrocarbons
Cycloalkanes : general formula CnH2n
Chpt:26 p.8
where = 3,4,5,………
Naming Method
<1>
<2>
<3>
Add the prefix cyclo—環 to the corresponding alkane name.
No need to assign the number when there is only one substitution.
Assign the lowest number when there are two or more substituted groups.
Examples
(B)
Nomenclature of Cyclic Unsaturated Hydrocarbons Naming method~
<1> No need to specify the position of the double bond when there is only one double bond in the ring.
<2> Assign the lowest number to the substituted groups.
Examples
(C)
Nomenclature of Cyclic Hydrocarbons with other functional groups
Order of priority for numbering the ring with the lowest possible numbers:
<1> principal group(s)
<2> Multiple bond(s)
<3> Prefixes taken all together
<4> Prefixes in alphabetical order
Example 1
HOOC
Cl
OH
_______________________________
OH
_______________________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
Example 2 :
Chpt:26 p.9
Naming monosubstituted derivatives of benzene with benzene as the parent name
________________________________________________________________
Example 3 : The substituent and the benzene ring are taken together to form a new parent name.
________________________________________________________________
Example 4
Two substituents on the benzene ring
1,2- as ortho(o)
1,3- as meta(m)
1,4- as para(p)
____________________________________________________________________________
____________________________________________________________________________
Example 5 :
More susbstituents on the benzene ring
____________________________________________________________________________
Example 6 :
The substituent is assumed o be position 1 when it is taken together with the benzene
ring to give a new parent name
____________________________________________________________________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
Chpt:26 p.10
Example 7 :The benzene ring be named as a substituents.
H3 C
CH2 CH2 CH CH3
CH2 Cl
CH2OH
__________________________________________________________________________
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
Exercises 1 :
Give the IUPAC names of the following compounds below:
Chpt:26 p.11
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
Chpt:26 p.12
Exercise 2:
Draw the structural formulae of the following compounds:
(a)
(c)
(e)
(g)
(i)
3-chloropentan-l -ol
cis-hept-3-en-5-yne
2-hydroxy-3-methylbutanonitrile
4-bromo-2-chloropentan-l -ol
2,4-dmitrobenzoic acid
(b)
(d)
(f)
(h)
(j)
2-ethylheptane-l,4-diol
trans-hex-4-en-2-ol
N,N-dimethylpropanamine
2,2,2-trichioroethanol
6-nitrocyclohex-2-enecarboxylic acid
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
2. Give the IUPAC names of he following compounds below: 1.
___________________________
2.
___________________________
3.
___________________________
4.
___________________________
5.
___________________________
6.
___________________________
7.
___________________________
8.
___________________________
9.
___________________________
10.
___________________________
11.
___________________________
12.
___________________________
13.
___________________________
14.
___________________________
15.
___________________________
Chpt:26 p.13
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
16.
___________________________
17.
___________________________
18.
___________________________
19.
___________________________
20.
___________________________
21.
___________________________
22.
___________________________
Exercise
Give the IUPAC name of the following compounds:
Write the structural formula of the following compounds:
23.
2, 5-dimethyl-3-hexyne
24.
4- (1, 4-dimethyl1entyl)-rnethylcYcloheXafle
25.
2-cyclopentylcyclohexane
26.
4-(I -propenyl)-2-methylcyctopentene
27.
2-chlorocyclohexanecarboxaldehyde
28.
ethyl cyclopropanecarboxylate
Chpt:26 p.14
L.S.T. Leung Chik Wai Memorial School
F.6 Chemistry
Chapter 26: Nomenclature
Answers
1.
2.
3.
4.
1-bromo-2-methylbutane
2-bromo-2-methylpropane
cyclopropane
20. trans-butenedioic acid
(N.B.: It is not necessary to number
the functional group.)
21.
N-ethylethanamide
22.
phenyl ethanoate
hepta-l, 3, 6-triene
5.
1 -ethyl-3-methylcyclobutane
(N.B.: The alkyl groups are numbered in alphabetical
order. See step 3(a) V)
6.
Chpt:26 p.15
2-(2-chloroethyl)-butane-l, 3-diol
(NB.: The carbon chain chosen should contain the
most principal gorups. See step 3 IB)
7.
2-propanamine
8.
3-bromo-2-hydroxybutanal
9.
2-aminopropanoic acid
10.
2-ethoxyethanol
11.
2-phenylethanol
12.
3.methoxyhexane
13.
2-phenoxyethanol
14.
cyclohexanecarboxylic acid
15.
phenylethanoic acid
16.
2, 4-dinitrobenzoic acid
17.
2,4-dichloropentane-1, 5-dioic acid
18.
5-hydroxy-4-oxopentanojc acid
19.
benzene-1, 3-dicarboxylic acid