Download Organic – Nomenclature – III

CHAPTER-III
IUPAC NOMENCLATURE OF COMPOUNDS
CONTAINING MORE THAN ONE FUNCTIONAL GROUP
Based on whether a group can be used as suffix in the root name(as parent compound)
or as prefix before the parent name(as branches), functional groups belong to the following
three types.
TYPE A: Groups which can be used only as prefix i.e as a substituent:
Name of the group
General formula
alkyl
Ralkoxy
ROalkylsulfanyl(alkylthio)
RShalo
Xnitro
NO 2alkenyl
R
CH CH
alkynyl
R C C
phenyl
C 6H 5cycloalkyl
cyclopropyl, cyclobutyl etc.
These 9 types of groups are used only as branches of the main chain. In otherwords
they are used only as prefixes to the parent compounds. They are never used as suffixes of
the root words to form the parent compounds. Therefore, they do not have any priority order
among them. Lowest set of locants rule is applicable to all of them to choose the direction
of numbering the longest chain.
CAUTION: The order in which these groups are placed in the above table is arbitrary.
No group gets any precedence over any other group to fix up the direction of numbering.
They all obey the lowest set of locants rule.
TYPE B: Functional groups which can only used as suffixes to form the parent compound.
Name of the group
structure
Alkene
Alkyne
*
*
These groups(ene and yne) enjoy the same priority. Do not mistake their relative
placement in the above table as priority order. The locants of enes and ynes commonly
obey the lowest set of locants rule. If the sets of locants for enes and ynes are same
in the two opposite directions of numbering the principal chain, in that case only ene
gets precedence over yne. Otherwise they enjoy the same priority and obey only the
lowest set of locants(for ene and yne) rule.
When enes and ynes are present in the longest carbon chain alongwith other functional
groups(type-C), then enes and ynes appear as co-suffixes with the seniormost functional
group. Therefore such groups are used as suffixes only. This may not be mistaken
for alkenyl and alkynyl groups which are used as prefixes. All these will be made
clear very soon.
TYPE C: Functional Groups which can be used both as a suffix to form the parent
compound or prefix to form a substituent
When a compound contains more than one functional groups belonging to type C
then, the one having the highest priority(called the principal functional group) will be used as
suffix to form the parent compound and all others will be used as prefixes(i,e as substituents)
of the parent compounds. Note that ene and yne functions belonging to type B groups appear
always as co-suffixes with the highest priority group in the parent name. This thing will be
clarified with a lot of examples later.
PRIORITY ORDER AMONG TYPE (C) FUNCTIONAL GROUPS
The following table gives the relative priorities or precedences of type-C functional
groups in decreasing order. The terms given in the prefix column are the names of the
functional groups when they are used as substituents(prefixes) and the terms given in the
suffix column are the suffixes used with the root words to form the parent compounds.
Name of group
carboxylic acid
sulfonic acid
structure
O
C OH
-SO3H
O
acid anhydride
ester
acid halide
C
O
O
C
O
prefix
suffix
carboxy
-oic acid
(carboxylic acid)
sulfo
sulfonic acid
-
alkoxycarbonyl
-oate
(carboxylate)
halocarbonyl
-oyl halide
(carbonyl halide)
C NH2
aminocarbonyl
-amide
(carboxamide)
C
cyano
-nitrile
(carbonitrile)
oxo
(formyl)
-al
(carbaldehyde)
C OR'
O
C X
O
acid amide
nitrile
aldehyde
ketone
alcohol
thiol
amines
-oic anhydride
N
O
C H
O
C
-OH
-SH
-NH2/-NHR/-NR2
oxo
-one
hydroxy
sulfanyl/mercapto
amino
-ol
-thiol
-amine
Nomenclature of Organic Compounds
Note that the suffixes given within parentheses in the above table are used only when
the carbon atom of the functional group is not included in the longest carbon chain. The usual
suffixes given are used when the carbon atoms of the groups are included in the longest
chain. Formyl is used as prefix(substituent) when the carbon atom of -CHO group is excluded
from the principal carbon chain. This will be made more clear soon.
General rules for naming compounds containing more than 1 functional group:
1.
The longest carbon chain giving the lowest locant to the highest priority group is found
out first for determining the parent compound. The C-C double bond or triple bond
is(are) accommodated in the longest chain(old rule). All other functional groups
appear as branches(prefixes) which are written first followed by the name of parent
compound. The ene or yne appear as co-suffixes with the highest priority group.
Example:
CH3
O
Cl
7
H3C
O
3
5
6
4
O
OH
1
2
OH
8
N
5-chloro-2-cyano-4-hydroxy-7-methoxy-6-oxooct-3-en-1-oic acid OR
5-chloro-2-cyano-4-hydroxy-7-methoxy-6-oxooct-3-enoic acid
In this molecule, there are 7 functional groups including the ene function. The functional
group having highest priority(see above table) is carboxylic acid(-COOH). So the parent
compound is a carboxylic acid(oic acid), not alcohol(ol), nitrile or a ketone(-one). The carboxyl
carbon is numbered 1 as per rule. All functional groups other than the highest priority
group(COOH) excepting the ene function are used as substituents and the names given in
the prefix column in the above table are used for naming these substituents. Ene is used as
a co-suffix before the suffix of the principal functional group(oic acid). The locant of ene and
oic acid are placed before the respective suffixes(ene and oic acid). The last letter e of ene
is dropped as it cannot face a vowel in -oic acid. The locant of oic acid(1) is usually not
written. You can write the name of the parent compound as oct-3-en-1-oic acid or oct-3enoic acid, the latter being the preferred name.
Example:
OH
Cl
4
H
2
O
5
3
1
O
OH
O
CH3
ethyl 4-chloro-3-hydroxy-2-(hydroxymethyl)-5-oxopentanoate
In this molecule, there are four functional groups namely ester, two hydroxy and aldehyde
groups. Since ester group has the highest priority among them, the parent compound is an
ester(alkanoate). The alkyl group of the alcohol part is written first as usual. This is followed
by the substituents of the longest alkanoate chain. The terminal aldehyde carbon(C-5) is a part
of the main chain, so the prefix oxo is used(not formyl). At C-2, the branch is hydroxymethyl
and at C-3 the branch is hydroxy while at C-4 the branch is chloro. Since the first word is
hydroxy in both the groups, the simple(or shorter) branch hydroxy is written first followed by
the complex(longer) branch hydroxymethyl.
2.
If the longest chain of equal lengths are available on two directions, then the one
associated with greater number of functional groups is taken as the principal carbon
chain for naming the parent. If the number of functional groups is same in both the
chains, then the chain bearing the higher priority functional group is taken as the
correct longest chain.
6
HO
5
NH 2
4
2
OH
3
1
O
O
H
6-am ino-5-hydroxy-4-(2-oxoethyl)hexanoic acid
In the above example -COOH is the principal functional group and so the parent
compound is alkanoic acid. Longest chain of six carbon atoms is available on both the
directions from C-4. The chain containing two functional groups(-OH and -NH2) is taken as
the correct longest chain. Note that although the other chain bears a higher priority group
(-CHO), still it is not considered as the principal chain for naming. The complex branch at
C-4 is 2-oxoethyl because the terminal aldehyde group(C=O) is included in the main branch
ethyl and hence is prefixed by oxo(not formyl). The name formylmethyl can be used in place
of 2-oxoethyl but the latter is the preferred name of the group.
NH2
H
O
O
O
6
5
4
3
1
6
5
1
2
NH2
O
O
4
3
OH
2
NH2
NH2
H
2-amino-5-methyl-6-oxohex-3-ynamide 2,6-diamino-5-formyl-6-oxohex-3-ynoic acid
In first case aldehyde carbon is included in the longest chain, not CH3 carbon. Note
that the longest chain(C-6) is available in both the directions from C-5. The longest chain
which has greater number of functional groups attached to it is taken as the correct longest
chain. That is why aldehyde carbon was taken in the main chain and the suffix oxo is used
for it, not formyl. Note that when aldehyde group remains as a part of the longest chain, it
will be expressed by prefix oxo. However if it remains outside the main chain, it will be
expressed by prefix formyl. Note thate yne has appeared as co-suffix with amide and the
Nomenclature of Organic Compounds
last letter e of yne has been deleted as it cannot face a vowel in the word -amide. The suffix
of amide(1) has also been deleted.
In the second case, between aldehyde and amide function the latter has greater
priority and so it is included in the principal chain, not aldehyde. For aldehyde, the prefix
formyl is used as it is outside the principal chain. For the amide, both the term oxo for the
C=O and amino for the NH2 groups were used in alphabetical order. Note that when derivatives
of carboxylic acids such as ester, amide and acid chloride are included in the main chain and
those groups are not highest priority groups in the chain, the prefixes used for them are as
follows.
functional group
amide
acid chloride
ester
prefixes used
both amino and oxo (not aminocarbonyl)
both chloro and oxo (not chlorocarbonyl)
both alkoxy and oxo (not alkoxycarbonyl)
Example:
H
O
O
6
4
2
4
5
3
Cl
1
OH
2
1
3
CH3 O
O
O
2-ethyl-4-formylhexanoyl chloride
4-methoxy-2-methyl-4-oxobutanoic acid
In the first case, aldehyde function has been excluded in the longest chain and the
prefix formyl has been used for that. In the second case, since carboxylic acid has higher
priority over ester function, the parent becomes alkanoic acid. Since ester carbon is included
in the main chain, two prefixes- methoxy and oxo have been used and arranged in alphabetic
order.
O
SO3 H
2
3
1
4
OCH3
4-methoxy-3-methyl-4-oxobutane-2-sulfonic acid
In this case, sulfonic acid has higher priority than ester, so the parent compound is
alkanesulfonic acid. Since ester carbon is included in the longest chain, two prefixes namely
methoxy and oxo are used as explained before. Sulfonic acid group gets the lowest locant.
Example:
O
3
H 3C
1
2
5
CH3
2
4
6
Cl
Br
OH
H2N
3
1
OH
7
4-bromo-2-chloro-6-hydroxyhept-5-en-3-one
3-aminopropan-1-ol
(not 3-hydroxypropan-1-amine
In the 1st case, keto function(one) has highest priority, hence the compound is a
ketone. So the carbonyl carbon has got the lowest locant(3). All other groups appear as
substituents except the ene function which appears as co-suffix with the principal function
-one. Note that here also the last letter e of ene has been deleted as it cannot face a vowel.
In this case, both the locants of ene(5) and one(3) have to be written for them separately
unlike aldehydes, carboxylic acid and its derivaties in which the suffix 1 is usually deleted.
In the 2nd case, since OH has the higher priority over NH2 group, the compound is
an alcohol(not amine). So the lowest locant has been assigned to the OH group. The NH2
function appears as a branch having prefix amino.
Example:
I
5
4
6
2'
2
3
Br
3'
1'
OH
CN
2-(2-hydroxy-1-methylpropyl)-3-iodo-4-methylhexanenitrile
1
Cl
2-bromo-5-chlorohexane
2-chloro-5-bromohexane(wrong)
In the first case longest carbon chain is C-6. The other direction would have given
shorter chain(C-5). Since nitrile is the principal functional group, it is an alkanenitrile. The
branch at C-2 is complex and is named as usual by following the rules for naming complex
branches.
In the second case, the set of locants are same on either direction(2,5) and hence the
alphabetical priority of bromo decides the direction of numbering.
PRESENCE OF CARBON-CARBON MULTIPLE BONDS IN THE CHAIN
(OLD RULE):
If the compound contains one or more carbon-carbon double or triple bonds alongwith
a functional group of type C, then the chain bearing both the functional group and maximum
number of double and triple bonds will be considered for naming the parent compound even
though it may not be the longest continuous carbon chain. Look at this example.
CH2
5
CH3
CH2
O
6
5
H3C
4
3
3
4
5-isobutylhex-5-enoic acid
H 3C
1
2
4
OH
2
3
2
1
O
CH3
1
O
CH3
isopropyl 2-(but-2-enyl]penta-2,4-dienoate
In the first example, the longest chain could have been C-8 starting from COOH
carbon. But the chain used for naming the parent compound is C-6, because in that chain the
C=C is included. In the second example, the longer chain could have been C-6 starting from
the carboxylate carbon. But the chain used for naming the parent compound is C-5, because
in that chain two C=C bonds are included while in chain containing C-6, one C=C is included.
Nomenclature of Organic Compounds
Since there are two double bonds in the chain the multiplying prifex di is used with ene. The
e of ene is dropped as usual. The root word pent is suffixed with letter ‘a’ to make penta.
Note that, if the compound does not contain a double bond or a triple bond, then
longest continuous carbon chain bearing the principal functional group is considered for naming
the parent compound. That longest chain may not also directly bear other functional groups
of lower priorities.
CH2
5
HO
2
3
2
4
1
OH
1
3
O
4-(3-hydroxypropyl)pent-4-enoic acid
O
5
H3 C
3
4
6
1
2
OH
COOEt
4-(ethoxycarbonyl)hexanoic acid
In the first example, the chain containing C=C is selected for naming the parent(C-5),
while the side chain containing OH group(a functional group having lower priority) has been
excluded from the principal chain used for naming the parent. In the second example,
COOEt(Et=ethyl)group has been excluded from the principal chain as the longest chain is C-6.
Conclusion: Maximum number of double and triple bonds are to be included in the
principal chain even if this chain may not necessarily be the longest.
NEW IUPAC RECOMMENDATION FOR NAMING COMPOUNDS
CONTAINING C-C MULTIPLE BONDS ALONGWITH HIGHER PRIORITY
GROUP(S) -(TYPE C GROUPS):
Like the naming for simple alkenes and alkynes, IUPAC has recommended provisionally
similar rules for naming compounds containing both type C functional group(s) as well as
C-C multiple bonds.
1.
The longest continuous carbon chain containing the highest priority group is selected
irrespective of whether C-C multiple bond remains within the chain or not. The double
and triple bond may be excluded from the longest chain if situation arises. In such
a case, branch containing the multiple bonds are named as alkenyl, alkynyl or alkylidene
or the like.
2.
The direction of numbering should be such that the highest priority group gets the
lowest locant.
Let us rename the first three compounds given before.
CH2
CH3
CH2
7
5
O
3
6
H3C
H3C
1
4
2
5
OH
8
O
2
4
CH3
6
3
1
CH3
O
7-methyl-5-methyleneoctanoic acid
isopropyl 2-(prop-2-enylidene)hex-4-enoate
CH2
HO
6
7
4
2
5
3
OH
1
O
7-hydroxy-4-methyleneheptanoic acid
In the first case, the C=C is excluded from the longest chain and the parent is octanoic acid
and the branch is methylene which is attached to C-5. Since methylene is a longer term than
methyl, it is placed after methyl.
In the second example, the longest chain is C-6 and hence the parent is hexenoic
acid. The branch becomes a alkenylidene group. Note that for a bivalent group idene is
suffixed to yl. Since there is a C=C at C-2 of the branch, the root becomes prop-2-enyl and
hence the whole bivalent group becomes prop-2-enylidene. The locant of oate(1) has been
deleted from the name of parent compound while ene appears as co-suffix with oate with
its locant 4.
In the third example, the C=C has been excluded from the longest chain of C-7.
=CH2 group becomes the methylene branch at C-4 and hydroxy being the branch at C-7.
IMPORTANT: The longest chain containing the highest priority group always gives the
parent compound whether or not this chain accommodates C-C double(s) or triple
bond(s). The students are advised to use the new rules with caution as these are not
officially published.
SAQ III.1: Give the IUPAC names of the following compounds from their line structures.
O
OH
(i)
(ii)
OH
COOH
O
NH2
Cl
(iv)
Br
OH
(vi)
OH
CN
COOH
O
CH3
(vii)
O
SO 3 H
H
(v)
(iii)
H3C
H3C
O
CH3
O
CH3
CHO
(viii)
Cl
S O3 H
Nomenclature of Organic Compounds
HS
OH
OH
(ix)
(x)
S
NH2
(xi)
H
CH3
CH 3
OH
H3C
CH3
(xii)
S
(xiii)
CH3
H 3C
OH
O
CH3
O
CH3
CH3
(xiv)H C
3
O
H3C
CH3
NITRILE GROUP ALONGWITH A HIGHER PRIORITY GROUP:
(EXCEPTION TO GENERAL RULE)
When -CN group is present in a compound along with another group having higher
priority, the carbon of -CN group is excluded from the principal chain used for naming the
parent compound. This is valid both when CN carbon remains as a part of the longest chain
as well as when it remains outside the longest chain. If CN remains in the main chain, then
that carbon is not numbered as it is excluded from the principal chain giving the parent
compound. This is an exceptional case unlike the case of aldehyde, carboxylic acid and other
derivatives of carboxylic acid -CN group is always excluded from the principal chain
and appears as a branch with the prefix cyano. See these examples.
6
4
3
2
1
OH
4
5
3
2
1
N C
O
4-cyano-2-methylbutanoic acid
CN
O
O
sec-butyl 5-cyano-2-methylpentanoate
In the first case, the CN group is excluded from the principal chain of 4 carbon atoms
although it is directly attached to it. In the second case also CN is excluded at C-5. Note
that if the group would have been -CHO(aldehyde) or other derivative of carboxylic acid
instead of CN in the second example, carbon atom of that functional group would have been
included in the principal chain, not CH3 carbon. But, since the group is -CN, it is to be
excluded and CH3 group is to be included. This is an exceptional treatment given to cyanide
group by IUPAC.
SAQ III.2: Name the following.
O
H
NH2
(ii)
(i)
H3C
N
CH3
N
CH3
O
POLYENES, POLYYNES AND ENYNES:
When a molecule contains more than one C=C double bonds, it is called a diene,
triene, tetraene, pentaene and so on. depending on the number of double bonds present and
in general, it is called a polyene. Similarly, when a molecule contains more than one triple
bond, it can be a diyne, triyne, tetrayne etc. and in general, called polyynes. When a
molecule contains both double and triple bonds, it is generally called enynes.
Rules for nomenclature:
(1)
The correct longest carbon chain is one which contains maximum number of
double and triple bonds(OLD RULE).
(2)
The multiplying prefixes di, tri, tetra, penta etc. are used with ene and yne depending
on the number of double and triple bonds present in the longest chain
(3)
Lowest set of locants for enes and ynes is considered while choosing the direction of
numbering.
(4)
If the sets of ene/yne locants are same on either direction, then ene gets the lowest
locant.
(5)
If the compound is a polyene or a polyyne(not an enye), and the sets of ene/yne
locants are same on either side, then lowest set of locants for the sustitutents decides
the correct direction of numbering.
(6)
The root word, prop, but, pent, hex etc. is suffixed with the letter a to make it propa,
buta, penta, hexa etc. if they are followed by the terms di, tri, tetra etc. This is
becasue a consonant in the root (prop, but, pent etc) cannot face another consonant
in di, tri etc. in the suffix. So by rule the letter a is suffixed to the root word. For
example-butadiene, hexatriyne etc.not buttriene, hextriene etc.
(8)
The locants of enes and ynes are prefixed before them. For example hexa-1,3,6triene, buta-1,3-diyne etc.
(9)
After the root word, ene comes first and then yne.
(10)
When ene faces a yne, the last letter e of ene is dropped, as y is taken to be a vowel
for naming purpose. For example- hex-1-en-3-yne.
(11)
If the branches contain double and triple bonds then they are named as alkenyl and
alkynyl as explained before (but-2-enyl, prop-1-ynyl etc.).
(12)
If chain of equal length containing same total number of enes and ynes compete for
longest chain selection, then the chain containing maximum number of enes gives the
correct longest chain.
(13)
If same number of total enes and ynes are present in two or more chains, then chain
containing maximum number of carbon atoms gives the correct longest chain.
See these examples and again study the rules for a better understanding.
Nomenclature of Organic Compounds
5
3
1
2
7
9
11
6
4
10
6
8
5
4
3
1
3
2
4
2
2
6
(V)
(IV)
hexa-1,3-dien-5-yne
but-1-en-3-yne
4-isopropyl-6-methyl-3-propylhept-5-en-1-yne
1
3
5
4
(III)
(I)
1
5-ethyl-7,9-dimethylundeca-4,6-diene
1
6
2
4
(II)
(I)
3-methylhex a-1,4-diene
7
3
5
Lowest set of locants for enes(1,4) gives the correct direction of numbering. The reverse
direction would have given the set 2,5. Note that the letter a is suffixed to hex to make
it hexa which is used before diene.
(II) Lowest set of locants of enes (4,6) gives the correct direction. The letter a has been
suffixed to dec(deca).
(III) The lowest set of locants for enes and ynes are jointly found out because both ene and
yne enjoy same priority. Here, yne gets lowest locant than ene. But while placing them
in order, ene comes before yne. Note that the last letter e of ene has been deleted as
it faces a vowel y. The root has not been suffixed with the letter a( not hepta) as it is
not facing di, tri, tetra etc. which begin with a consonant.
(IV) In this case, set of ene and yne locants are same on either side(1,3). In this case ene
gets precedence and the locant of ene should be lowest. Here also the last letter e of
ene has been deleted.
(V) Here also the sets of locants are same on either side. So ene gets precedence. The root
hex has been prefixed with the letter a(hexa) as it is facing diene. The last letter e of
diene has been deleted as it is facing the vowel y.
More examples:
1
4'
5'
2'
3'
1'
7
4
2
3
5
2-(2-ethyl-3-methylpentyl)-3-methylpenta-1,3-diene
5
6
3
4
2
1
4-vinylhept-5-en-1-yne
In the first case the principal chain for naming is C-5 as it contains both the double
bonds. The other direction after C-2 would have given the longest chain(C-7), but according
to old rule that is not the principal chain. Instead that part became a branched substituent
(i.e a complex branch) and has been named as per rule.
In the second case the longest chain(C-7) containes one ene and one yne. So, we
had to exclude one ene from the main chain and is used as a substituent(vinyl).
CH 3
CH3
5
2
CH 3
6
7
2'
4
1
3
3
H 2C
1'
CH2
4
2
6
5
1
3'
CH
4-(prop -1-enyl)hepta-1,4-dien
3-ethynyl-4-neopentylhexa-1,5-diene
In the first case, there were two directions of getting the longest chain of C-7. But
we chose the one as the correct longest chain which gives the lowest set of ene/yne
locants(1,4). The other direction would have given the set 1,5. Thus, the side chain attached
to C-4 becomes the alkenyl branch(prop-1-enyl).
In the second case, diene and enyne compete for the longest chain. In such case,
according to rule(rule 12), ene is to be included in the main chain and yne to be excluded.
So the parent compound is hexa-1,5-diene and there is ethynyl substituent at C-3. Note that
neopentyl can also be written as 2,2-dimethylpropyl. But neopentyl is the preferred name of
the branch.
USE OF BIVALENT ALKYLIDENE GROUPS :
H3C
4
CH 3
CH2
5
6
H 3C
2
3
H2C
4
5
2
3
CH 2
7
7
6
CH 2
9
8
1
1
CH 3
CH
H 3C
10
5-ethylidene-7-vinyldec-1-en-9-yne
3-sec-butyl-6-methyl-4-methylenehepta-1,5-diene
In the both cases, the longest chains containing maximum number of enes and ynes
do not contain the other C=C bearing group which is attached as a bivalent alkylidene group
or monovalent alkenyl or alkynyl group to the main chain.
SAQ.III.3: Write the IUPAC names of the following compounds.
H3C
CH3
HC
CH
CH2
(ii)H3C
(i)H C
3
CH3
H3C
CH2
H2C
Nomenclature of Organic Compounds
H3C
CH2
CH3
CH3
H2C
(iii)
CH
CH3
H3C
CH3
CH3
CH2
H3C
CH2
(iv)
CH3
(v)
H3C
CH3
CH3
NEW IUPAC RULES FOR NAMING POLYENES, POLYYNES AND ENYNES:
Like naming simple alkenes, alkynes and other functional compounds containing enes
and ynes, the naming of polyenes/polyynes/enynes is done in similar manner according to the
provisional recommendations of IUPAC made in Janurary 2002.
1.
The longest continuous carbon chain is found out irrespective of whether it
accommodates maximum number of multiple bonds or not. It may accommodate the
minimum number of multiple bonds or even no multiple bonds in it if situtaion so
arises. The branches containing C-C multiple bonds are named as alkenyl, alkynyl,
alkylidene, alkenylidene, alkynylidene or the like.
2.
Lowest set of locants rule is followed as usual for choosing the direction of numbering
without giving any weightage to the branches containing the multiple bonds. But
multiple bonds contained in the longest chain are given weightage as usual.
Examples:
2
CH
H3C
3
CH3
1
6
4
6
8
7
5
5
4
CH3
9
2
CH3
1
H2C
7
3
H3C
4-ethynyl-2-methyl-4-vinylheptane(new name)
3-isobutyl-3-propylpent-1-en-4-yne(old name)
CH2
CH
5-(prop-2-ynylidene)-4-vinylnona-2,7-diene(new)
4-(but-2-enyl)-5-vinylocta-3,6-dien-1-yne(old)
In the first example, according to new rules, the longest chain does not contain any
of the multiple bonds. It is an alkane with vinyl and ethynyl as branches. According to old
rules both ene and yne are included in the principal chain of C-5 with propyl and isobutyl
as the branches. In the second example, according to new rules, the longest chain of C-9
contains only two C=C bonds. Hence vinyl and prop-2-ynylidene are the branches of nonadiene.
According to old rules, the longest chain is taken to be C-8 which contains maximum number
of multiple bonds(two double bonds and one triple bond) and more number of branches.
4'
3'
2'
1'
9
11
8
10
7
2
4
6
3
5
1
6-(2-methylbuta-1,3-dien-1-yl)undeca-2,4-dien-7-yne
In the above example, the chain containing four C=C would have been C-10, but that
has not been taken as the principal chain. Rather longest chain of C-11 containing three
multiple bonds(two double bonds and one triple bond) is taken as the principal chain.
2-methylbuta-1,3-dien-1-yl group can be written as 2-methylbuta-1,3-dienyl by deleting 1 as
the locant of yl. Its name according to old rule is 5-(but-1-ynyl)-3-methyldeca-1,3,6,8-tetraene.
3.
If two chains of same length compete for longest chain out of which one chain
includes one or more number of multiple bonds and the other excludes them or
contains less number of multiple bonds then the chain containing more number of
multiple bond is taken as the correct longest chain even if that chain bears less
number of branches(violates branching rule). This is same as per the old rule.
H3C
CH3
6
H3C
4
5
3
7
CH3
(3-tert-butylhepta-1,5-diene)
2
CH2
1
In this case the longest chain of C-7 is available in two directions- one excluding one
C=C and the other including it. According to rule the one contanining C=C bond is taken as
correct longest chain even if that is connected with less number of branches.
CAUTION: The students should name compounds according to new rules only when
required as these rules have not yet been published officially although they have been
recommended by IUPAC since 2002. They should be familiar with both the systems.
COMPOUNDS CONTAINING TWO OR MORE IDENTICAL FUNCTIONAL
GROUPS:
1. POLYOL:
*
Molecules containing more than one OH groups are called polyols eg. diol, triol,
tetraol etc. Their IUPAC names are alkanediol, alkanetriol and so on. The letter e of
alkane is not to be deleted as it is facing a consonat in di, tri, tetra etc. The polyol
is to be prefixed with its locants. Lowest set of locants for the ol functions decides
the correct direction of numbering the longest chain. If this set tallies on two directions,
then lowest set of locants for the branches decides the correct direction.
*
The longest carbon chain holding maximum number of OH groups should be taken
as the principal chain. For that purpose, the chain may not be the actual longest
continuous carbon chain. If two chains having same length contain same maximum
Nomenclature of Organic Compounds
number of OH groups then first lowest set of locants for ol functions is considered
which is followed by branching rule and finally the lowest set of locants for the
branches for choosing the direction of numbering.
Br
3
1
OH
CH2
OH
2
CH2
OH
ethane-1,2-diol
OH OH
5
4
6
CH2
3
4 OH
2
CH2
1
OH
OH
propane-1,2,3-trio
5-bromohexane-2,4-diol
(et hylene glycol)
CH
OH
2-buty lbutane-1,4-dio
(glycerol)
In the first three examples, the longest chain holds all the OH groups. But in the
fourth example, the chain holding both the OH groups is C-4 and it is taken as the principal
chain for naming the parent compound. The names given inside parentheses are the common
or trivial names of the compounds which are accepted as systematic alternative names for
them by IUPAC.
OH
1
2
5
3
CH3
4
H 3C
6
OH
OH
3-(1-hydroxyethyl)hexane-1,4-diol
In the above example, the longest chain holds a maximum of two OH groups, so other
OH group remains in the branch called 1-hydroxyethyl. The longest chain(C-6) is available
in two directions. Both the chains also contain same number of branches(3). Hence, lowest
set of locants for the ol functions(1,4) as against (2,4) decided the correct name.
POLYAMINES :
Compounds containing more than one amino groups are called polyamines. It can be
primary amino group(-NH2), sec-amino group(-NHR) or tert-amino group(-NRR’). The rules
for naming such compounds are same as for polyols discussed before. See these examples.
CH3
2
4
6
CH3
5
H3C
NH2
NH
7
1
NH2
2
NH
8
H3 C
3
1
3
CH3
CH3
CH3
4
7-methyloctane-3,5-diamine
N,N’,2-trimethylbutane-1,3-diamine
In the first example, both are primary amino groups while in the second example both
are sec- amino groups. That is why N,N’ locants were used in the second example. Lowest
set of locants for amines has been considered in both the examples to choose the direction
of numbering.
POLYONES
*
Compound containing two or more keto functions is called a polyone eg. dione, trione
etc. The IUPAC name of such a compound is alkanepolyone eg. alkanedione,
alkanetrione etc. with the locants of one preceding polyone(eg hexane-2,4-dione).
The last letter e of alkane is not deleted because it is facing a cosonant in dione,
trione etc. The lowest set of locants for the one functions holds good for deciding
the direction of numbering.
*
The longest carbon chain containing maximum number of keto functions is taken as
the principal chain for naming the parent. Other keto function if any remains in the
side chain(eg. 2-oxoethyl, 2-oxopropyl etc.)
CH3
10
CH3
9
CH3
8
3
5
4
H3C
7
CH3
2
O
1
H3 C
6
1
O
O
6
5
3
CH3
4
2
O
O
3-ethyl-5-methylhexane-2,4-dione
5-(1-oxoethyl)decane-2,7-dione
or 5-acetyldecane-2,7-dione
In the first example, the longest chain of C-6 contains two C=O functions, so
hexanedione is the parent compound. In the second example, the longest chain of C-10
contains two C=O function. The other C=O remains outside the longest chain and is used as
a substituent named as 1-oxoethyl(acetyl). The branch 1-oxoethyl is more popularly called
acetyl and has been accepted by IUPAC.
DIALS
Aldedyde(al) function appears at the terminal postions. Hence, there can be two
aldehyde groups in the longest chain. Only dial is possible and not beyound that. More CHO
functions can remain outside the longest chain as branches. The IUPAC name of dial is
alkanedial. The locants of al functions are usually deleted as they always appear at the
terminal positions. The lowest set of locants for the other substituents linked with the chain
is considered for naming. Note that the carbon atoms of both the aldehyde groups always
remain included in the main carbon chain.
O
H
O
O
C
C H
ethanedial
(oxalaldehyde)
H
O
C CH2 C
propanedial
(malonaldehyde)
O
H
H
O
CH2 CH2 C
butanedial
(succinaldehyde)
C
H
Nomenclature of Organic Compounds
The names given inside parentheses, although trivial in their origin are more preferred
as the systematic names by IUPAC.
O
H
5
O
3
4
2
1
H
2-methylpentanedial
Note that locants of al(two terminal carbon atoms in each case) are not used before
the term dial. The lowest set of locants for the substituents has been considered while
choosing the direction of numbering.
DICARBOXYLIC ACID:
If a molecule contains two COOH groups, it is a dicarboxylic acid and it is named
as alkanedioic acid. Since oic acids occupy the terminal positions, their locants are not used
in the name. Both the carboxyl carbon atoms are included in the main chain.
O
HO
C
O
C
OH
HOOC
ethanedioic acid
(oxalic acid)
HOOC(CH2)3COOH
(pentanedioic acid/glutaric acid)
HOOC(CH2)4COOH
(hexanedioic acid/adipic acid)
COOH
HO OC
CH2
CO OH
CH2 CH 2
butanedioic acid
(succinic acid)
propanedioic acid
(malonic acid)
1
5
COOH
COOH
2
4
3
2-ethyl-4-isopropylpentanedioic acid
In the last example, the branch ethyl gets precedence over isopropyl for the former’s
alphabetical seniority.
The names given inside parentheses, though trivial in origin are preferred names by
IUPAC.
DIESTER, DIAMIDE, DI(ACID CHLORIDE) AND DINITRILE:
All the other derivatives of carboxylic acids containing two identical functional groups
are named as follows:
diester: dialkyl alkanedioate
diamide: alkanediamide
di(acid chloride): alkanedioyl dichloride
dintirile: alkanedinitrile
In all these cases the carbon atoms of the two functional groups are included in the
main chain.
Examples
H2N
O
O
3
O
5
4
4
1
2
2
3
5
O
1
O
6
O
2-ethyl-5-methylhexanediamide
NH2
diisopropyl 2-methylpentanedioate
CH3
H3C
CH3
O
CH3
O
O
O
1-ethyl 5-isopropyl 2-methylpentanedioate
Cl
4
2
1
3
5
Cl
O
O
3-ethyl-2-methylpentanedioyl dichloride
6
NC
4
5
3
2
1
CN
2,4-dimethylhexanedinitrile
In the 3rd example, the diester contains two different alkoxy alkyl functions(-OR’). In such
a case the two alkyl groups(-OR’) are first arranged according to alphabetical order with the
locants of the carboxyl carbon prefixed before them.
COMPOUNDS CONTAINING THREE OR MORE IDENTICAL FUNCTIONAL
GROUPS SUCH AS AL(ALDEHYDE), OIC ACID, OATE, OYL CHORIDE, AMIDE,
AND NITRILE:
Case-I: Longest chain bearing all functional groups:
The continuous carbon chain can include the carbon atoms of the two functional
groups of the types mentioned above. If the third functional group(s) is(are) directly attached
to the main chain; then the carbn atoms of all the functional groups including those present
in the continous chain are excluded for determining principal chain for naming the parent
compound. The functional groups are used as suffixes according to the format given below.
The parent compound becomes an alkane. The lowest set of locant rule for the functional
groups and then for the substituents hold good in choosing the direction of numbering. The
locants of the functional groups appear before the suffixes such as tricarboxylic acid,
tricarboxylate etc.
alkane tricarboxylic acid(acid);
trialkyl alkanetricarboxylate(ester);
alkane tricarbaldehyde(aldehyde);
alkanetricarbonitrile(nitrile);
alkane tricarboxamide(amide);
tricarbonyl trichloride(acid chloride)
Nomenclature of Organic Compounds
O
O
O
O
2
2
4
OCH2CH3
O
OH
1
3
4
butane-1,1,2-tricarboxylic acid
O
triethyl pentane-1,2,3-tricarboxylate
H 3C
H
H
O
3
CN
CH 3
3
5
6
2
4
1
CN
O
Cl
1
Cl
2
O
OCH2CH3
5
O
HO
1
3
CH3CH2O
OH
1
Cl
CN
H
propane-1,2,3-tricarbaldehyde
O
O
2-methylhexane-1,3,4-tricarbonitrile methanetricarbonyl trichloride
In the last example the set of locants 1,1,1 has been deleted since the parent alkane
is methane.
Case-II: Compound containing more than two identical functional groups out of
which two are included in the longest chain and other ones are not directly attached
to the main carbon chain:
Look at the following example.
1
HOOC
3
2
7
5
4
6
4
5
COOH
3
2
1
CN
CN
CN
COOH
4-carboxymethylheptanedioic acid
3-cyanomethyl-2-methylpentanedinitrile
When the third identical functional group is not directly attached to the longest carbon
chain containing two other identical functional groups in the terminal positions, the naming is
done in the usual way, not like the previous case. In this case two functional groups are
included in the longest chain to find the parent compound and the third which is not directly
attached to the longest chain is excluded from it. The group containing the third functional
group becomes a substituted alkyl group such as carboxymethyl, (2-carboxyethyl), cyanomethyl,
(2-oxoethyl), (2-alkoxy-2-oxoethyl) etc. See some more examples
3'
COOCH2 CH3
2'
1'
CHO
1'
1
OHC
5
3
2
2'
4
6
CHO
2-methyl-3-(2-oxoethyl)hexanedial
1
CH3CH2O OC
3
2
4
7
5
6
8
COOCH2 CH 3
diethyl 3-methyl-5-(3-ethoxy-3-oxopropyl)octanedioate
Note the group (2-oxoethyl) can be named as formylmethyl in the first example
above and the group(3-ethoxy-3-oxopropyl) could be named as (2-ethoxycarbonylethyl) in
the second example above, but these latter ones are not the preferred names. Usually the
prefix formyl for aldehyde, alkoxycarbonyl for ester, halocarbonyl for acid halide, aminocarbonyl
for amide groups are used only when the main carbon chain bears only the above mentioned
groups as substituents(not as substituted alkyl groups as given in the above examples) and the
longest chain includes another higher priority group than these.
SAQ III.4: Write the IUPAC names of the following.
O
NH2
H2N
HO
O
O
NH2
O
(i)
(ii)
H
NH 2
O
O
NH 2
NH 2
O
NH2
O
(iii)
(iv)
H3 C
O
NH2
O
O
O
H2N
H 2N
O
O
O
O
CH3
OH
O
(v)
(vi)
O
O
O
(vii)
Cl
O
HO
O
HO
O
OH
OH
O
H3C
(viii)
CH3
NH
CH3
(ix)
H3C
NH
CH3
O
CHO
Cl
O
H3C
(x)
(xi)
Cl
Cl
CHO
CHO
O
O
(xii)H3C
O
O
CH3
O
CH3
CH3
SAQ.III.5: Draw the structures of the following.
(i)
(ii)
(iii)
ethyl 6-cyano-4-methyl-3-methylenehepta-4,6-dienoate
methanetricarbaldehyde
2,3,4,5,6-pentahydroxyhexanal
Nomenclature of Organic Compounds
(iv)
(v)
2,3,6-trimethyl-3-vinylocta-1,6-dien-4-yne
3-(2-amino-2-oxoethyl)pentanediamide
PARENTHESIS METHOD OF WRITING STRUCTURAL FORMULA
The structures of organic molecules can be condensed by using the parentheses
format. See these examples.
CH
H 3C
(CH 3 ) 2 CHC(CH
3 ) 2 COOH
CH
H 3C
p a re n th e sis fo rm u la
3
C
COOH
COOH
CH
3
c o n d e n se d stru c tu ra l
fo rm u la
lin e stru c tu re
The two methyl groups put inside the first parenthesis are attached to the carbon
atom shown adjacent to the first parenthesis. Similarly, the other two CH3 groups put inside
the second parenthesis are directly attached to the carbon atom shown adjacent to the second
parenthesis. So, before naming the compound change the parenthesis formula to either line
structure or the condensed structural formula. Then name as usual. The name of the above
compound is 2,2,3-trimethylbutanoic acid. See one more example.
(CH3 )3 CCH(CH 3 )COC(C H3 )2 (CH 2)2CHCHCOOCH(CH 3)CH 2CH 3
H3 C
H3 C
CH 3
C CH
O
C
CH 3
C CH 2 CH 2 CH
CH 3
CH
CO O CH CH 2 CH 3
CH 3
CH 3
sec-butyl 6,6,8,9,9-pentamethyl-7-oxodec-2-enoate
Three CH3 groups in the first parenthesis are attached to the carbon atom placed
adjacent to it. The subsequent CH3 group is attached to the carbon atom adjacent to it. Next
CO is a C=O. The subsequent two CH3 groups are also attached to the carbon atom adjacent
to them. (CH2)2 means CH2 groups are repeated two times in the main chain. Note that
(CH2)n means CH2 groups are repeated n times in the main carbon chain. This is because
CH2 group cannot remain outside the main chain as it is divalent (-CH2-). The next CHCH
is CH=CH double bond. Simiarly in the alkyl group of ester function the CH3 in the parenthesis
is attached to to carbon adjacent to it. Note that you have to check the valency of carbon
at every carbon and then decide whether it is C=C or C-C, C=O or C-O. The name of the
compound is sec-butyl 6,6,8,9,9-pentamethyl-7-oxodec-2-enoate.
SAQ III.6: Write the IUPAC names of the following from their condensed structures.
(i) (CH3)2CHCH(OH)CH(CHO)C(CH3)2 CONH2
(iii) CH3 CH(CH3)OC(CH3)3
(ii) (CH 3)3CNHCH(CH 3)CH2CH3
(iv) OHCCH(CH3)(CH2)3COC(CH3) 2CCCH(CH3)2
NOMENCLATURE OF CYCLIC COMPOUNDS
1.
The carbon atom of the ring attached to the highest priority group is numbered 1. If
there is a C=C double bond in the ring, then ene should get the lower locant. In the
absence of a C=C, lower locant or lower set of locants rule is applicable to choose the
direction of numbering in the ring.
HO
OH
1
6
5
1
H3C
2
O
6
3
2
5
3
4
4
cyclohex-2-en-1-ol
6-methylcyclohex-2-ene-1-carboxylic acid
O
6
5
1
4
2
CH3
3
OH
4-hydroxy-2-methylcyclohexanone
In the 1st case the carbon atom of the cyclohexane ring attached to OH group is
numbered 1. The numbering direction is chosen in the manner so as to assign lowest locant
to the ene. Same considerations have been given in the second example. Note that COOH
group or in fact any other carbon bearing group like -CHO, -CONH2, -CN etc. attached
to the ring are not included in the longest carbon chain. Therefore, they are suffixed as
carboxylic acid,(-COOH) carbaldehyde(-CHO), carboxamide(-CONH2), carbonitrile(-CN) and
so on, in the manner done before in open chain(aliphatic) compounds. In the 3rd example,
the locant of one has been deleted(cyclohexanone). When there is one suffix, the locant 1
is not used but when there are two or more suffices, the locant 1 is used.
H
O
H2N
CH3
1
1
2
6
6
3
5
5
4
O
O
2
3
4
2-ethylcyclohexanecarbaldehyde 5-oxocyclohex-2-ene-1-carboxamide
N
Cl
O
1
6
2
1
HO
6
5
O
2
3
4
H
5-formylcyclohex-2-ene-1-carbonitrile
5
3
4
6-hydroxycyclohex-3-ene-1-carbonyl chloride
Nomenclature of Organic Compounds
In all the structures containing C=C, the ene has been given the lowest locant
irrespective of the position of the other functional groups like OH, CHO, CO etc. attched
to the ring. In the last example, the name could have been 2-hydroxycyclohex-4-ene-1carbonyl chloride if OH group would have received the lowest locant. But this is wrong in
the naming of ring compuonds. If C=C is present, priority would be given to that. If there
is no C=C, then lowest set of locant rule comes into force. Look at these examples.
O
O
H3C
HO
2
2
3
1
1
HO
NH2
6
4
6
3
5
4
5
O
3-aminocyclohexanol
methyl 2-hydroxy-5-oxocyclohexanecarboxylate
H3C
3
2
1
H3C
CH3
1-isopropyl-3-methylcyclohexane
In the first example, C-1 is assigned to the carbon bearing ester group. Lowest set
of locants assigns C-2 to OH group. In the second example, the carbon bearing OH group
gets C-1 as it is senior to NH2 group. In the third example, both the branches are alkyl and
the set of locants are same on either direction. So alphabetical priority is considered to give
lowest locant to isopropyl(C-1).
NAMING COMPOUNDS CONTAINING BOTH CYCLIC(ALICYCLIC) AND
ACYCLIC(ALIPHATIC OR OPEN CHAIN) PARTS:
RULES :
1.
If the principal functional group is attached to the aliphatic part, then the parent
becomes aliphatic compound. This remains valid even if the cyclic part contains more
no of carbon atoms.
2.
If the principal group occurs in two or more carbon chains that are not attached
directly to one another but are separated by, for instance, a ring or hetero atom(eg.
N, O, S etc), then that chain is chosen as parent for nomenclature which carries the
largest number of the principal groups. If the numbers of these groups in two or more
chains are the same, then greater number of carbon atoms in a chain is considered.
If that tallies then lowest set of locants is taken into consideration.
4
3
2
1
CO O H
3'
3''
2''
1''
HO CH2 CH2 CH2
3-cyclohexylbutanoic acid
4'
2'
OH
1'
1
2
CH CH2 OH
1-[4-(3-hydroxypropyl)cyclohexyl]ethane-1,2-diol
In the first case, -COOH group is attached to the aliphatic(open chain) part. Therefore the
parent compound is butanoic acid.
In the second case, there are two aliphatic portions in between the ring structure. The
one containing 2 OH groups was considered for parent name(ethane-1,2-diol). The sustituent
at C-1 of the parent compound is named following the rules for naming a complex branch.
The main branch cyclohexyl is substituted at the 4 position by 3-hydroxypropyl group. Note
that there are three numbering systems i.e one for the parent chain, the other for the main
branch(cyclohexyl) and the third for the sub-branch of the main branch.
3.
If the principal group occurs only in the cyclic ring, then that ring forms the parent
for nomenclature.
4.
If the functional groups occur both in aliphatic chain and in cyclic ring, the parent
for nomenclature is that portion in which the highest priority group occurs in larger
numbers. In otherwords, the part containing highest priority functional group gives the
name of the parent compound irrespective of number of other functional groups of
lower priority occurs in the other part. If the highest priority groups are the same
in the two portions then the cyclic ring is considered for naming the parent compound.
2
1
1'
1
3'
OH
HO
2-ethylcyclohexanol
(2-ethylcyclohexan-1-ol)
2
CH CH2
OH
2'
OH
1-(3-hydroxycyclohexyl)ethane-1,2-diol
NH2
NH2
CH3
O
H2N
O
NH2
OH
2-(8-amino-8-oxooctyl)cyclohexanecarboxamide 1-(2,4-diaminocyclohexyl)propan-1-ol
In the first case the functional group -OH is present in the cyclic ring, so the parent
is cyclohexanol. Note that the parent cyclohexanol could have been cyclohexan-1-ol. Since
numbering of the ring has started from the carbon which bears OH group, the locant of ol
must be 1. In such case, the locant 1 is usually dropped in cyclic systems.
In the second case, more number of -OH groups are present in the aliphatic
part, so the parent is ethane-1,2-diol, not cyclohexanol.
In the third case, the both the ring and aliphatic portions contain the same group(amide),
then the ring is considered for naming the parent compound although the aliphatic part has
greater number of carbon atoms.
In the fourth case the highest priority functional group is present in the aliphatic part,
so the parent becomes aliphatic even though there are greater number of functional groups
of lower priority in the cyclic part.
Nomenclature of Organic Compounds
More examples:
O
1
O
5
4
2
3
OHC
CH2 C CH2 CH3
O
CH2 (CH2)7 CHO
4-(9-oxononyl)cyclohexanecarbaldehy
4-(2-oxobutyl)cyclopentane-1,2-dione
OH
6
Cl
1
CO OH
Cl
2
HO
5
Cl
4
3
3
2
1
4
6
O
OH
4,5-dichloro-2[4-chloro-1-(hydroxymethyl)-5-oxohexyl]cyclohexanecarboxylic acid
COOH
5
(2,3-dihydroxycyclohexyl)acetic acid
In the first example there are two keto functions in the cyclic part, so cyclic part
became the parent compound. In the second example, both the parts contain the same
aldehyde(CHO) group, hence the cyclic part is taken for naming the parent even though the
acyclic part contains more number of carbon atoms. In the third example, the cyclic part
contains the highest priority group among the two parts. So cyclic part became the parent
compound. The locant of carboxylic acid(1) has been dropped. In the fourth example, the
highest priority group is present in the acyclic part hence the parent became acetic acid. The
locant of (2,3-dihydroxycyclohexyl) is 2 which has been dropped because there is only one
position(2) in acetic acid for bearing a substituent.
SAQ III.7: Write the IUPAC names of the following.
H 2N
O
O
CH3
OH
(i)
CH3
O
OH
(ii)
(iii)
O
HO
H 3C
CH3
CH3
HO
(iv)
(v)
CH3
OH
CH3
NH2
CH3
HO
H3 C
CH3
(vi)
COOH
(vii)
(viii)
CH3
CH3
NOMENCLATURE OF AROMATIC COMPOUNDS:
Benzene and related compounds are called aromatic compounds.
H
C
H
C
C
H C
C
C
H
H
H
(BENZENE)
Benzene is a six membered ring containing alternate C-C single bonds and C=C
double bonds. Each carbon is attached with one H atom. In the line structure(middle) the C
and H atoms are not shown. Benzene can also be shown by a graphic formula(last structure)
in which a circle is drawn inside a hexagon. This is called the resonance hybrid structure
of benzene. Benzene and aromatic compounds are cyclic compounds like alicyclic compounds
such as cyclohexane, cyclopentane etc. but they exhibit completely different properties.
Monosubstituted Benzene:
*
All the six H atoms in benzene are equivalent. If any one H atom is replaced by any
other group, we call it a monosubstituted benzene. The IUPAC names of some
common monosubstitued benzenes are given below.
Cl
CH 3
1
OH
NO 2
NH2
CHO
COOH
2
COCH3
benzaldehyde benzoic acid acet ophenone
phenol
toluene chlorobenzene
nitrobenzene aniline
(1-phenylet hanon
(hydroxybenzene)
(methylbenzene)
(aminobenzene)
CN
COCl
CONH2
COONa
COOCH3
benzonitrile benzoyl chloride benzamide sodium benzoate methylbenzonate
OCH3
methoxybenzene
(anisole)
O
benzophenone
(diphenylmethanone)
The names given within parentheses are the alternative names which are less preferred.
Note that the substituent can be attached to any carbon atom of the ring as all the 6 carbon
atoms are equivalent. Conventionally, we attach a group at the uppermost or upper right
positions.
Nomenclature of Organic Compounds
*
If the substituent contains one or more carbon atoms which bears the functional
group or in otherwords the functional group is not directly attached to the benzene
ring, then it is named as phenyl substituted aliphatic compound. Note that if a caron
bearing functional group like -CHO, -COOH, -COOR, -CONH2, -CN etc is directly
attached to the ring then the compound gets an aromatic namen as given before.
OH
COOH
OH
phenylacetic acid
phenylmethanol
triphenylmethanol
SAQ III.8: Write the IUPAC names of the following compounds.
CH3
H3 C
CH2 CH3
COCH2CH3
CH
OCHCH3
COOCH(CH3)2
I
(iii)
(ii)
(i)
(iv)
(v)
(vii)
(vi)
SAQ III.9: Write the IUPAC names of the following.
CHO
CH3
(i)
O
NH2
Cl
(ii)
H3C
CH3
CN
(iii)
(iv)
(v)
CH3
O
DISUBSTITUTED BENZENE
When two substituents are attached to the benzene ring at two different carbon atoms there
can be three position isomers.
Y
2
6
5
3
4
1,2- or ortho
(i)
X
X
X
1
1
1
6
6
2
4
3
5
3
5
2
Y
1,3- or meta
4
Y
1,4- or para
1,2- or ortho(o-)disubstituted benzene: When the two substituents are attached to
any two adjacent carbon atoms, then it is called 1,2- or ortho or in short o- disubstituted
benzene. When two groups are same(X), then you can assign C-1 to any of the two
carbon atoms of the ring to which substituents are attached, so that the other carbon
atom will be C-2. But when the groups are different(X and Y), then C-1 is assigned to
that carbon of the ring which bears the higher priority functional group.
(ii) 1,3- or meta(m-)disubstituted benzene: When the two substituents are attached to
1st and 3rd carbon atoms, it is called 1,3- or meta or m- disubstituted benzene. Note that,
like o-disubstituted compound, you can assign C-1 to any carbon atom if the two
substituents are same(X). But, if they are different(X and Y), then C-1 is assigned to
that carbon which bears the higher priority functional group.
(iii) 1,4- or para(p-)disubstituted benzene: When the two substituents are attached to 1st
and 4th carbon atoms, it is called 1,4- or para or p-disubstituted benzene. Note that, like
o- and m-disubstituted compounds you can assign C-1 to any carbon atom if the two
substituents are same(X). But if they are different(X and Y), then C-1 is assigned to
that carbon which bears the higher priority functional group.
Note that, when X and Y are different the parent of the aromatic compound is determined
according to the higher priority group.
PRIORITY ORDER AMONG FUNCTIONAL GROUPS:
The priority order among the functional groups(type C) upto -NH2 group is same as
given for aliphatic compounds before.
-COOH >-SO3H > -COOR’ > COCl > CONH2 > -CN > -CHO > -COR > -OH > -NH2
Note that like for the aliphatic compounds there is no relative priority among groups
like -OR(alkoxy), -R(alkyl), -X(halo), -NO2(nitro), alkenyl and alkynyl which belong to the
type-A category. When there are two groups from this category then C-1 is assigned to
that carbon atom of benzene ring which bears the alphabetically senior group.
See the following examples.
2
COOH
HO
2
1
3
1
NH2
CN
3
2
4
1
OHC
HO
4-formylbenzonitrile
salicylic acid
3-aminophenol
(p-formylbenzonitrile)
(2-hydroxybenzoic
(m-aminophenol)
acid/ o-hydroxybenzoic (not 4-cyanobenzaldehyde) (not 3-hydroxyanilin
acid)
CH2 CH 3
CH 3
CH3
1-methyl-3-vinylbenzene
(3-vinyltoluene)
Cl
1-chloro-3-methy l benzen
OCH3
1-ethy l-4-m ethoxy benzen
The prefix o-(for ortho), m-(for meta) and p-(for para) can be used in place of
locants 2, 3 and 4- respectivly with respect to C-1. In the first case the higher priority group
is -COOH, so the carbon atom of benzene ring attached to -COOH group has been numbered
1. Then direction of numbering is chosen according the lower set of locants rule. Its common
name(salicylic acid) is the preferred IUPAC name. In the 2nd and 3rd examples, -CN and
Nomenclature of Organic Compounds
-OH groups have higher priorites over -CHO and -NH2 groups respectively(refer priority
order given before). In the 4th, 5th and 6th examples, the branches do not have any relative
priority among them and so the alphabetically senior group has been numbered C-1.
*
When two groups are identical, the multiplying prefix di- is used with the name of
the substituent eg. 1,2-dinitrobenzene, 1,3-dihydroxybenzene etc. Carbon bearing
functional groups eg. -COOH, -CHO, -CN etc. are to be expressed as suffixes like
1,2-dicarboxylic acid, 1,3-dicarbaldehyde, 1,4-dicarbonitrile of the parent benzene and
not as derivatives of benzoic acid, benzaldehyde and benzonitrile respectively. The
common names of some compounds have been accepted as preferred IUPAC names.
The beginnners are advised to familiarise both the systematic and preferred names.
OH
OH
OH
COOH
OH
COOH
OH
OH
resorcinol
phthalic acid
hydroquinone
(1,3-dihy droxy
(quinol/1,4-dihy droxy (benzene-1,2-dicarboxy lic
benzene/o-dihy droxy benzene/p-dihy droxy acid)
benzene)
benzene
pyrocatechol
(1,2-dihydroxy
benzene/o-dihydroxy
benzene)
COO H
CH 3
CH 3
COO H
CH3
CH 3
COO H
COO H
isophthalic acid
(benzene-1,3dicarboxylic acid)
CH 3
terephthalic acid
(benzene-1,4dicarboxylic acid)
o-xylene
(1,2-dimethyl
benzene/o-dimethyl
benzene)
NH 2
NH 2
m-xylene
(1,3-dimethyl
benzene/m-dimethyl
benzene)
NH 2
NH 2
NH 2
NH 2
CH 3
p-xylene
(1,4-dimethyl
benzene/p-dimethyl
benzene)
*
benzene-1,2-diamine benzene-1,3-diamine
(1,2-diam inobenzene/ (1,3-diam inobenzene/
o-pheny lenediam ine) m -pheny lenediam ine
)
benzene-1,4-diamine
(1,4-diam inobenzene/
)
p-pheny lenediam ine
If out of the two substituents, one contains one or more carbon atoms which bear
a higher priority functional group, it is named as a substituted aliphatic compound.
However if the higher functional group is directly attached to the benzene ring, then
it is named as a substituted aromatic compound. If the aliphatic and aromatic parts
possess identical functional group, then the compound is named as aromatic.These
set of rules are same for any compound containing both acyclic and cyclic parts as
we had discussed before.
CH3
COOH
CHO
HOOC
H3C
HO
HO
(4-hydroxyphenyl)acetaldehyde
1
CH3
4-(2,2-dimethylbutyl)phenol
H 3C
OH
2
4-(carboxymethyl)benzoic acid
NH2
1
OH
2
2
CH3
3
1
OH
NH2
phenylmethanol
2-(1-amino-1-methylethyl)phenol
(3-aminophenyl)methanol
SAQ III.10: Write any one IUPAC name of the following aromatic compounds.
CH3
COOH
CH2CH3
Cl
NH2
NO2
SO3H
O2N
CN
Cl
Cl
NO2
Cl
COCl
CH(CH3)2
O 2N
NO2
COCH3
CONH2
CHO
Br
NO2
CONH2
COOC2H5
C2H5
OC H 2 CO OH
Cl
H2NOC
CHO
I
CH3
CN
Cl
SAQ III.11: Write the preferred IUPAC names of the following compounds.
CN
H3C
CH3
NH2
CHO
N
CH3
CH3
(i)
(ii)
(iii)
CH3
CH3
CHO
CHO
(iv)
CH3
CH3
COOH
COOH
(v)
NO2
Nomenclature of Organic Compounds
TRI- AND POLY- SUBSTITUTED BENZENE :
(i)
When benzene ring is attached with more than 2 substituents, then the functional
group(type C) having the highest priority gets the lowest locant(1). The parent name
of the compound(eg. phenol, benzoic acid, aniline etc) is assigned accordingly. The
numbering direction is chosen while keeping the lowest set of locants rule in mind.
If all the substituents belong to type-A category having no relative priority then lowest
set of locants is considered for naming the compound. Alphabetical seniority of the
groups is not considered for the purpose of assigning the lowest locant as we
were doing for disubstituted benzenes. See these examples.
Br
6
4
NO 2
Br
OH
5
2
1
3
1
Br
1
3
1,2,3-tribromobenzene
CH 3
5-hydroxy-2-methylbenzoic acid
6
4
3
NC
1,3,5-trinitrobenzene
CONH 2
2
1
NH2
1
1
HO
3
3
5
5
COCH3
4-acetyl-2-formylbenzonitrile
Br
Br
3
2,4,6-tribromoaniline
OH
2
6
4
6
2
NO2
4
CHO
Br
5
2
5
O2 N
COOH
2
6
4
2,6-dihydroxybenzamide
In the 2nd and 3rd examples the three groups are identical. So lowest set of locants
rule has been followed. In all other examples, there is one or more substituents belonging
to type C. In such case, the carbon atom of benzene ring bearing the highest priority group
has been numbered 1. Then the lowest set of locants is considered for choosing the direction
of numbering.
2
CH3
3
4
H2N
Cl
1
1
2
O2N
4-chloro-2-methyl-1-nitrobenzene(correct)
5-chloro-2-nitrotoluene(wrong)
5
Cl
4
O2N
3
5-chloro-2-nitroaniline(correct)
2-amino-4-chloro-1-nitrobenzene(wrong)
In the 1st example, -CH3, -NO2 and -Cl have no relative priority as they belong to
type A category and hence lowest set of locants decides the correct name. But in the 2nd
example, -NH2 group belongs to type C functional group and the other two belong to type
A. Hence, the locant of amine(parent compound is aniline) has been 1 and then lowest set
of locants is considered for choosing the direction of numbering. In the example below only
lowest set of locants has been considered as all the branches belong to type A.
CH2CH 3
4
3
2-chloro-4-ethy l-1-m ethoxy benzene
2
1
OC H3
Cl
(not 3-chloro-1-ethy l-4-m ethoxy benzen
SAQ III.12: Name the following compounds.
COCH3
COOCH3
CH3
COOCH3
C 2H5
CH3
O 2N
NO 2
Br
CHO
COCl
NO 2
OC 2H5
I
H 3C
NH 2
O 2N
NO 2
NO 2
H 3C
Cl
Cl
COOCH3
O 2N
COOH
Cl
CH3
POLYNUCLEAR AROMATIC COMPOUNDS:
Compounds containing more than one benzene ring fused at the ortho or 1,2 positons
are called polynuclear or condensed aromatic compounds. A few examples are given below.
5
1
8
2
7
3
6
5
4
9
1
4
3
6
or
2
7
1
8
(napthalene)
8
2
6
3
5
4
3
6
or
2
7
9
8
4
10
10
5
7
1
(anthracene)
When two benzene rings are fused, it is called naphthalene. The IUPAC rules for
numbering the carbon atoms in the rings have been shown. The carbon atoms at the fusion
positions(ortho) are not counted while numbering. Similarly when three benzene rings are
fused, it is called anthracene. The two pairs of carbon atoms present at the fusion points
are not counted while numbering. After completing the numbering of one terminal ring(either
clockwise or anticlockwise), the carbon atoms of the other terminal ring are numbered
bypassing the middle ring. The middle ring is numbered at the last(9 and 10). The numbering
in naphthalene and anthracene can also start from the left terminal ring in the same way as
the right terminal ring. Condensed aromatic compounds containing 4, 5 rings are called
tetracene and pentacene respectively. Condensed aromatic systems having greater number
of rings also exist but their discussion will not be made here.
Examples:
CHO
1
2
OH
4
6
3
2
6
1
2-naphthol
5
H5C 2
1
COOH
1-naphthoic acid
CH3
3
5
2
1
NH2
4
6-methyl-1-naphthaldehyde
6-ethyl-2-naphthylamine
Nomenclature of Organic Compounds
CH3
CH3
1
2
4
CN
5
6
3
3
2
7
2
8
1
1-methyl-2-naphthonitrile
4
5
1
NH2 SO3 H
COOH
5-methylanthracene-1-carboxylic acid 8-aminonaphthalene-1-sulfonic acid
Note that lowest set of locant rule is not applicable in condensed system. Although
the highest priority group will get the lowest locant, the numbering procedure will remain the
same as shown before.
SAQ.III.13: Name the following compounds.
Cl
OH
CONH2
Cl
HO
NH2
CH3
OH
CH3
COOH
Cl
HETEROCYCLIC COMPOUNDS:
Cyclic compounds containing atoms like O, N or S besides carbon atoms in the ring
are called heterocyclic compounds. A few simple heterocyclic compounds and their numbering
systems are given below with their line structures.
4
4
4
3
4
3
5
5
2
2
N
H
O
1
furan
1
pyrrole
3
5
2
5
3
6
2
S
N
1
1
thiophene
pyridine
4
4
3
5
5
2
6
N
H
O
O
6
3
2
1
O
1
piperidine
tetrahydrofuran(THF)
2H-pyran
4H-pyran
All the other positions than the O, N or S are occupied by carbon atoms which are
attached to required number of H atoms. In the last two examples, 2H and 4H signify the
presence of saturated carbon atom(sp3 hybridised) at the positions 2 and 4 respectively.
Pyran contains one O atom, five carbon atoms and two C=C in a six membered ring. There
are two isomeric pyrans(2H and 4H). More discussion on naming heterocyclic compounds
will not be made here.
NOMENCLATURE OF BICYCLIC COMPOUNDS:
The compounds in which two rings are fused with each other having one or more
sides(C-C bonds) in common to both the rings are called bicyclic compounds. In these
compounds the two rings share at least two carbon atoms. The number of shared carbon
atoms can also be more than 2.
Bridgehead carbon atoms:
Any carbon atom which is connected with 3 or 4 other carbon atoms is called a
bridgehead carbon atom. In bicyclic compound bridgehead carbon atom is connected with
3 other carbon atoms. There are two bridgehead carbon atoms in a bicyclic compound.
bridgehead carbon
bridges
bridgehead carbon
In the 1st example two 4-membered rings are fused at the 1,2 positions. In the 2nd
example, one 8 membered ring is fused with with another 6 membered ring at the 1,2,3
positions. In the 3rd example, two 3-membered rings are fused at the 1,2 positions. The
bridgehead carbon atoms are shown in the diagramme by arrow marks. Each bridgehead
carbon atom is connected with 3 other carbon atoms.
BRIDGES:
With respect to the bridgehead carbon atoms there are three bridges. The carbon
chain connecting the bridgehead carbon atoms is called a bridge. There are three
bridges in a bicyclic compounds which have been shown in the diagramme. Note that a
bridge can be merely a covalent bond connecting the bridgehead carbon atoms as you can
see in the 1st and 3rd examples given above. In such a bridge there is no carbon atom.
Definition of a bicyclic compound:
A bicyclic compound is one which can be converted to an open chain acyclic
compound by making cleavage(scission or breakage) of covalent bonds two times. The
diagramme below shows how successive cleavages for two times converts a bicyclic compound
into an open chain compound.
1st cleavage
2nd cleavage
open chain
NAMING BICYCLIC COMPOUNDS:
(i)
There is a main ring and a main bridge. The two longer bridges alongwith the
bridgehead carbon atoms constitute the main ring. The other bridge becomes the
main bridge. In the above example the two terminal bridges are longer while the
internal bridge is the shortest consisting of a covalent bond only(no carbon atom).
Hence the main ring contains six carbon atoms including the bridgeheads. The internal
bridge which is excluded from the main ring becomes the main bridge.
Nomenclature of Organic Compounds
(ii)
The name of the compound contains three parts as shown below
bicyclo[x.y.z]alkane
The three numbers x, y and z separated by full stops are written in decreasing order
within square bracket. These numbers determine the size or the number of carbon atoms
present in the three bridges. The bridgehead carbon atoms are not included in these numbers.
If a bridge does not contain any carbon atom( i.e when it is merely a covalent bond), this
number is taken to be 0.
(iii)
All the carbon atoms including the bridgehead ones are considered for the name of
parent alkane.
2
2
0
3
1
5
1
0
1
bicyclo[2.2.0]hexane bicyclo[5.3.1]undecane bicyclo[1.1.0]butane
Naming substituted bicyclic compounds:
(iv)
The numbering of the bicyclic compound starts from one bridgehead carbon atom via
the longest bridge to the other bridgehead carbon atom. Then the numbering is
continued around the main ring upto the last carbon atom which appears before the
1st bridgehead. After that the numbering is continued with the carbon atoms of the
main bridge(shortest bridge). Note that the carbon atom of the main bridge closer to
C-1 gets the lowest number among all the carbon atoms of the main bridge. Note
also that the main bridge containing no carbon atom(only covalent bond) does not get
any more number after the end of the main ring.
(v)
The numbering starts from that bridgehead which gives lower locant to any functional
group, multiple bond or any substituent present in the longest bridge. If there is no
branch in that bridge then lower locant is received by a branch in the shorter and
shortest bridges. The priority order remains the same as for other compounds expecting
the inclusion of carbon-carbon multiple bonds in this case.
-COOH >-SO3H > -COOR’ > COCl
> -NH2 > C
C >
C
> CONH2 > -CN > -CHO > -COR > -OH
C
(Note that in aromatic compounds alkenyl and alkynyl groups are excluded from the
benzene ring while in bicyclic compounds C-C multiple bond can remain as a part of the ring.
In such a case ene and yne have their precedence over all other type A groups)
Substituents are written before the prefix bicyclo. The suffix ane of alkane changes
to ene or yne if there is double or triple bond. The suffix -ol, -one, -al, -oic acid etc. can
be used in place of ‘e’ of alkane if there is a functional group. The locants of the functional
groups are to be used as usual like the nomenclature in aliphatic compounds. See these
examples.
H 3C
2
10
1
H3C
5
4
3
3
3
11
9
4
H3C
2
4
7
6
1
2
5
6
8
5-m ethylbicyclo[2.2.0]hex-2-ene 3-methylbicyclo[5.3.1]undec-8-ene
1
4-methylbicyclo[1.1.0]but-1-ene
CH 3
OC H 3
4
6
8
3
10
4
5
7
5
HO
9
6
2
O 2N
1
3
9
7
1
2
8
6 -m ethylb icyclo[5 .2 .1 ]d ec-3 -ene 4- m ethoxy-2-nitrobicyclo[3.2.2]nonan-6-ol
In the 1st example, since two bridges are of same length(2 carbon atoms) the
direction of numbering which gives lowest locant to ene has been chosen. In the 2nd
example, the numbering starts from the bridge head which gives lower locant to ene(8). Had
we started the numbering from the other bridge-head, the locant of ene would have been
greater(9). In the 3rd example, two bridges are of same length ( 1 carbon atom) so ene gets
priority over methyl substituent. In the 4th example, ene gets the lower locant as it has higher
priority over methyl group. In the 5th example, the main ring contains the highest priority
-OH group in the shorter bridge. Although numbering is first completed in the longest bridge
according to rule, it is done in such a direction(clockwise)that the -ol(alcohol) gets the lower
locant(6). Numbering in anticlockwise direction whould have given the locant 7 to the -ol
function.
SAQ III.14:Write the names of the following bicyclics.
CH3
H3C
(i)
(ii)
(iii)
CH3
(iv)
(v)
H 2N
(vii)
(vi)
OHC
COOH
(viii)
(ix)
(x)
H2 N
H 2N
NOMENCLATURE OF SPIRO COMPOUNDS
The compounds in which two rings share one common carbon atom are called
spirocompounds.
The IUPAC name of such compounds is as follows.
spiro[x.y]alkane
x and y are chain lengths in the two rings or the number of carbon atoms in the two rings
which link to the common atom(called spiro atom), which are separted by full stop. Note
that the spiro atom is excluded in these numbers. The numbers are written in increasing order
eg. [4.5] unlike that followed in bicyclic compounds(decreasing order). While naming the
parent alkane the total number of carbon atoms in the compound is counted.
Nomenclature of Organic Compounds
6
1
7
2
5
8
3
4
10
9
spiro[4.5]decane
Note that ring sizes are 4 and 5 on the two sides of the common or spiro atom which
are written in increasing order with full stop in between them.
(iii)
Naming substituted spirocompounds: The numbering starts in the smaller size
ring from the carbon atom adjacent to the spiro atom and proceeds around the smaller
ring back to spiro atom and then proceeds around the second ring(larger size ring).
While going from the smaller ring towards the larger ring the lowest set of locants
rule is kept in mind. If there is a C=C, then ene should get the lower locant compared
to alkyl or other type A groups.
6
4
5
5
3
6
7
1
3
4
6
4
7
2
3
8
2
5
1
10
8
7
9
8
2
9
H3C
H 3C
8-methylspiro[2.5]oct-4-ene
1
spiro[4.4]nona-2,7-diene
1-ethylspiro[3.6]dec-6-ene
SAQ III.15: Name the following spiro compounds.
H 3C
(i)
(ii)-
(iii)
(iv)
Cl
(v)
CH3
H3C
H3C
H3C
CH3
ALTERNATIVE NAMING PROCEDURE FOR ETHERS AND 20 AMINES
Ethers:(OXA System)
1.
Oxygen atom in ether is treated like a carbon atom in finding out the longest continuous
chain including the oxygen atom. In otherwords, the oxygen atom is counted like a
carbon atom in determining the the name of parent alkane. The ether group(oxygen
atom) is indicated by the prefix oxa with its locant placed before it. Lowest set of
locants rule is followed while choosing the direction of numbering. Note that ether
group (O atom) does not enjoy any priority as functional group.
5
3
CH3
1
H3C
2
O
6
4
(2-methyl-4-oxahexane)
CH3
Note that IUPAC does not have a fixed procedure for naming ethers, although the one
discussed before(alkoxyalkane) is the preferred name. The oxaalkane procedure of
naming ether is simpler, although used to a lesser degree of preference.
SAQ III.16: Write the names of the ethers as oxaalkanes. Also give their other
preferred names as alkoxyalkanes.
H3C
H3C
O
O
CH3
O
CH3
H3C
CH3
H3C
(i)
(ii)
CH3
H3C
CH3
H3C
CH3
(iii)
CH3
CH3
CH3
H3C
CH3
Cyclic ethers:
When oxygen atom remains as a part of a ring, it is a cyclic ether. The systematic names
of these ethers and their alternative names according to oxa system are given below.
O
O
O
O
O
1,4-dioxacyclohexane
oxacyclopentane
oxetane
(1,4-dioxane)
(oxacyclobutane) (tetrahydrofuran or THF)
oxirane
(oxacyclopropane)
Note that oxirane is also commonly called ethylene oxide or epoxyethane.
Sec-amines (AZA System)
Like oxygen atom in ether, the nitrogen atom in a sec-amino group( NH) is counted like
a carbon atom in finding out the longest continuous chain. The prefix aza is used for the amino
function with its locant before it.
4
H3C
5
2
NH
OH
1
3
3-azapentanoic acid [ 2-(ethylamino)acetic acid/N-ethylglycine]
O
SAQ III.17: Draw the structure of the following compounds.Also give their preferred names.
(i) 5-aza-3,4-dimethyloctan-2-one
(ii) azacyclohexan
Nomenclature of Organic Compounds
SUBSTITUTED OXIRANES(EPOXYALKANES), IMINES, LACTONES,
LACTAMS, IMIDES, KETENES
1. Substituted oxirane: The O atom of oxirane is always numbered 1. Alphabetical seniority
of alkyl groups decides the correct direction of numbering. These are also named as
epoxyalkanes, the locants of the epoxy are to be prefixed to it.
1
O
3
H 3C
CH
2
CH
CH
2
CH
3
2 -e th yl-3 -m e th ylo x ira n e
(2 ,3 -ep o x y p en ta n e)
2. Imines: =NH is called imine group. It is a bivalent group. The name of imine is alkan-ximine where x is the locant of imine.
H 3C
H 3C
CH
2
CH
2
CH
CH
NH
3
NH
b u ta n -1 -im in e
p ro p a n -2 -im in e
3. Lactones: Cyclic esters are called lactones. Butyrolactone, valerolactone, caprolactone
are a few examples of lactones.
H 2C
H 2C
H2
C
CH
H 2C
O
C
H 2C
CH
2
C
CH
O
2
O
-b u tyrolacton e
 -v alero lacton e
CH
H 2C
2
CH
H 2C
C
O
2
2
O
O
-cap rolacto n e
4. Lactams: Cyclic amides are called lactams. Butyrolactam, valerolactam, caprolactam are
few examples of lactams.
H 2C
H 2C
H2
C
H 2C
NH
C
O
-butyro lactam
H 2C
CH 2
C
CH 2
CH 2
H 2C
NH
H 2C
O
-valero lactam
CH 2
CH 2
C
NH
O
-capro lactam
5. Ketenes: R-CH=C=O are called ketenes. Such compounds are named according to IUPAC
rule.
Example: CH3-CH=C=O prop-1-en-1-one
6. Imides: Imides contain -CO-NH-CO- group. It is analogous to acid anhydride except
-O-in anhydride is replaced by -NH- in imide. They are named according to IUPAC rules.
CH3-CO-NH-CO-CH3
N-acetylacetamide.
PRACTICE QUESTIONS
SET-I: Write the IUPAC names of the following compounds.
CH3
(a)
CH3
CH C
CH 3
CH3
(b)
OH CH3
H3 C
C
(d)
CH CH3
C
CH3
(c) ClCH2CH CH
C
CH3
CH2
H
C
CH
3
(f)
CH3
H
CH3 O
CH C O CH2 CH3
CH3
C CH3
CH3
(h)
CH3 O
H3 C C C
CH2 CH3
CH3
CH3
H3 C CH2 CH
O
CH3
CH3
(e) H3 C CH CH
CH3 CH3
CH3
(g)
C
CH 3
O
H3 C CH C
C
Cl
CH3
H3 C C CH
(i)
CH3
CH3
CH2 C NH2
O
CH3
H3 C
(j)
CH3
C NH CH
CH3
CH
3
SET-II: Write the IUPAC names of the following compounds.
(a) (CH3 )2 CHCH(CH3)C(CH 3) CH2
(b) (CH3 )3COH
(c) (CH3 )3 CCH2 NH2
(d) (CH3 )3CC(CH3 )2 COOCH3 (e) CH3CH(CH3 )C(CH3)2 CHO (f) CH3 CH(C2 H5)COOCH(CH3)2
O
O
(g) (CH ) C C
3 3
O
C
C(CH 3)3
(h) (CH 3)2 CHOCH2 CH 3
(i) (CH3 )2CHCH2C
CC(CH3 )3
(j) (CH 3)3CCN
SET-III: Write the IUPAC names of the following.
(a)
(b)
O
(c)
OH
H3 C
H3 C C C O Ca
(d)
H3 C
O
2
Nomenclature of Organic Compounds
O
C
N
(e)
(f)
O
C
(g)
(h)
Br
NH
O
O
(i)
H
(l)
H
O
(k) CH 3SCH2CH3
(j) Br
CH3
(CH3) 2CHCH(SH)C(CH3)3
(m) (CH3)3CCH2NCS
SET-IV: Draw the structural formual of the following.
(a) 2,3-dimethylbutan-2-ol
(c) 3-ethyl-2,3-dimethylpentanoic acid
(e) 2-methylbutanoyl chloride
(g) 2-ethoxy-3-methylbutane
(i) 2-methylbut-2-ene
(b) 2,2-dimethylpentanal
(d) N-ethyl-N,2-dimethylpropan-2-amine
(f) ethyl 2-methylpropanoate
(h) 3,3-dimethylpentan-2-one
(j) acetic 2-methylpropanoic anhydride
SET-V : Write the IUPAC names of the following compounds.
H3C
H3C
CH3
CH3
CH3
(a)
(b)
H3C
H3C
CH3
(c) (CH3 )2 CHCH2OH
CH3
H3C
H3C
CH3
CH3
CH3
CH3
(d) (CH3 )3CCH2 CHO
H3C
(e)
(f) CH3 CHCHCH2 OC(CH3)3
CH3
OH
(g) (CH3)2CHCH2COOC(CH3)3
(i)
CH2 C
(h) CH3 CH2 CH(CH3 )CH2CH(CH2CH3)CH2 CH2 CH3
CH(CH3)2
CH2CH3
SET-VI: Give the structure for the following.
(a) cyclohexanecarbaldehyde
(b) hexa-1,4-diyne
(c) 5-methylhept-5-en-1-ol
(d) cyclopent-2-en-1-amine
(e) bicyclo [2.2.2]octane-2,5-dione
(f) 2,3-dimethyloctanedioic acid
(g) 4-tert-butyl-2-methyloctane
(h) 3-methyl-6- (prop-1-enyl) cyclohex-1-ene
(i) 5-(1,2-dimethylpropyl)undecane
(j) propane-1,2,3-tricarboxamide
(k) 7-methylbicyclo[4.1.0]hept-2-ene
(l) 2-phenylethanol
(m) 4,4-diemthylpentan-2-one
(n) 1-isopropyl-2-methylpropyl thiocyanate
Set-VII : Write the IUPAC names for the following structural formulae.
OH
O
CH3
CH3 CH
(a)
CH
CH 3 Cl
C
CH
CH 3
O
CH2 CH 3
(b)
Cl
HC
OH
(c)
H3C
O
OH
NH2
CO2 H
(d) (CH3 )3 C CH2 CH
H2 C
H3C
(e)
NH2
CO
Br
(i)
CH 3CH 2NH CH 2CH 2 C
H 3C
OH
CH 2CH 3
CHO
NH 2
NH2
O
CH3
CH 3
CH3
OH
CH 3
(h)
H3 C
CH3
H3C
OH
CHO
(g)
CHO
(f)
NHCH 2CH3
COOH
(j)
(k)
H3C
CH3
(l)
O
CH3
Cl
CH3
HO
H 3C
CH3
CH3
H3C
H 2C
(m)
(n)
(o) (CH3 )2CHCOCH2CH3
OH
CH3
OH
SET VIII : Draw structural formula for each
(a) 1-cyclopentyl-2,2-dimethylpropan-1-one
(c) p-chlorobenzoic acid
(e) 4-methoxybut-2-ynoic acid
(g) 2,4,6-tribromononanenitrile
(i) tetraisopropylammonium chloride
(k) diethyl 6-(3-isopropoxy-3-oxopropyl)2-methylundecanedioate
(m) (4-formyl-3-hydroxy-2-methylhex3-enenitrile
of the following compounds.
(b)Ethyl cyclobut-2-enecarboxylate
(d)sec-butyl 4-methylpent-3-enoate
(f) N-methyl-N-phenylacetamide
(h)4-methylcyclohex-2-en-1-one
(j) (allyloxy)methylbenzene
(l) 4-methoxy-2-methylhex-1-ene
(n) 4-ethoxy-2,3-dimethyl
-5-oxopentanoic acid
(o)
SET IX: Write the IUPAC names of the following structures.
CH3CH2CHC
(a)
CCH3
CH3
(b) C6 H5 CH2 OCH2CH(CH3 )2
(c) OHC(CH2)3 CO2 H
(d)
(e) (CH3 )3CCH(CH3 )CH2NHCH3
(f)
(g) CH3CH(CH3)CHCHCO2C(Cl)(CH3)CH2CH3
(h)
CH2 COCl
CH2 Cl
(CH 3)3CCH CCH2 CH(CH 3)CO 2H
Br
Nomenclature of Organic Compounds
CH
CH 2
H3C
(i)
(j)
NO2
(k) (CH 3)2 CHNHCH 2CH(CH3 )(CH2 )2CO2 CH2 CH(CH3 )2 (l) NC
CO NH2
H3C
O
OH
CH3
(m)
(n)
HO
O
O
H3C
CH3
(o)
NC
(p)
H3C
CH3
SET-X: Draw the structural formula of the following compounds.
(a) 5,6-diethyl-2,3,7-trimethylnonan-3-ol
(b) isobutyl 3-phenylbutanoate
(c) 4-isopropyl-3-phenylcyclohexanone
(d) 3-(1,2-dimethylpropyl)-4-ethylphenol
(e) 3-nitroaniline
(f) 2-isopropoxypropane
(g) 7-methylspiro[2.4]hept-4-ene
(h) N,3,3-trimethylpentanamide
(i) 6-methylocta-1,3,5-triene
(j) 5-(1-cyanoethylidene)-6-methyloct-3-ynoic acid
(k) 4,4-diethylcyclohexa-2,5-dien-1-one
(l) 3-bromo-4-cyclopropylcyclobutane-1,2-diol
SET-XI: Write the IUPAC names for the following compounds.
OH
(CH3 )3CCCH2 CH2 CH(CH3)2
(a) (CH 3)2C CHC(Cl) CHCH CHCO 2 H
(b)
CH2CHCH2 CH3
OH
(c) CH3C(CH3)2CH(C6H5)COCH3
(d) H2NCH2CH(OH)CH2CH2CH2NH2
C2 H5
CO2 C2 H5
(e)
(f)
O
OH
OCH3
Cl
O
(g) C6 H5 CC
CH
C6 H5
(h) [(CH3 )3C]3CH
O
CH3
O
C2 H5
(i)
Cl
(j)
OH
I
O
O
(k) CH CH C O C
3
2
(l)
(CH3 )3 CCOO
COOH
(n) H3 C CH2 CH2 O Na
(m)
COOH
CH3
H3C CH2 CH S Na
(o)
CH3
(p)H3C
CH3
OCN
SET-XII: Draw the structures for the following names.
(a) phenyl 2-methylbut-2-enoate
(b) 3-aminohept-5-enamide
(c) 4-(4 chlorophenyl)pentanoic acid
(d) 4-(N,N-dimethylamino)butan-2-ol
(e) 4-amino-2,2-dimethyl-4-oxobutanoic acid (f) 1,1,3-triphenylprop-2-en-1-ol
(g) 3,3-dimethylhex-4-yn-2-one
(h) 2-methylcyclohexane-1,3-dione
(i) 6-methylcyclohex-1-ene-1-carbonitrile
(j) 3,4-dimethylphenol
(k) 2-iodo-1-methoxy-4-methylbenzene
(l) potassium ethanethiolate
(m)
SET-XIII: Write the IUPAC names for the following compounds.
CH 3
(a) CH 2(OH)CH(OH)CH2(OH)
(b)
C CH2
H3 C
CO OH
Br
(d) H3 C
(c) ClCH2CH2Cl
Cl
Cl
CH
C
CH2OH
Cl
O
(e)
HO
O
C
C
OH
(f)
H3 C CH CH
O
(g) H3 C
CH
CH
CHO
CH
CH3
Br
O
(h) H C C CH C
3
2
CH 3
Nomenclature of Organic Compounds
CH 3
(i)
H 3C
CH 2
Cl
CH
C
(j)
CH
CH 2
Br
O
Cl
CH3
Br
(k)
O
H3C
CH3
(l) Cl CH2 C
CH3
CH
C
CH3
Cl
OH
(m) H3 C
C
C CH
CH
CH3
(n) CH3 O
CH(CH3)CH
CHCOOCH(CH3 )2
CH3
O
(p) HOO C(CH2 )4 COOH
(o) CH3 C CH2 COOH
O
(q)
H3 C
CH CH CH
C Cl
(r) CH3CH(OH)CH(CH3 )COCH3
CHO
Cl
(s) PhCH 2CH(CH3 )COOCH(CH3 )CH2 CH3
CH3CH(CH3)CHCH(CH 3)
(u)
O
(w)
C
O
CH2 CH C
CH2 CH CH2
C(CH3) CH2
CH
(v)
CH CH2
H
(t)
H
(y)
H3 C
CH
(x) (CH3 )3CCH(CH3 )NHCH(CH3)2
O
OH
NH2
C CH CH CN
OCH(CH3)CH2CH3
CH 2OH
Cl
CHO
CH3
CH2
OH
(z)
NH2
SET-XIV: Write the IUPAC names of the following compounds.
COOEt
H3C
CH3
H3C
N
HOOC
COOH
COOH
(a)
(b)
H3C
CH3
O
OH
CH3
(c)
(d)
H3C
CH3
(e)
(f)HO
O
O
O
C H 3
CH3
O
O
O
HO
H3C
(g)
(h)
NH
H3C
CH3
H3C
CH2
CH3
CHO
(i)
(j)
EtOOC
HO
NH2
CH3
O
H3C
(k)
H3C
NH
N
(l)
CH3
CH 3
CH3
NH 2
H3C
CH3
NH2
(m)
OH
CH 3
(n)
(o)
CH3
CH3
H3C
Nomenclature of Organic Compounds
SET XV: Write the IUPAC names of the following.
O
CH2
H3C
OH
(i)
(ii)
H3C
CH3
CH2
CH2
O
CH3
NH
H2C
(iii)
CH3
H3C
CH3
OH
(iv)
CH3
NO 2
Cl
Cl
Br
CH3
(v)
(vi)
CH3
OH
CH 3
H2C
(vii)
(viii)
H3C
NH2
N
CH3
CH3
CH3
CH3
H3C
O
CH3
CH 3
(ix)
H
COOH
O
NH
(x)
H3C
CH3
OH
CHO
(xi)
(xii)H3C
(xiii)
CH
OHC
CHO
CH3
H3C
OH
CH3
O
(xiv)
O
(xv)
SET-XVI:
CH3
H3C
CH3
(a)
(b)
CH3
CH3
H2C
CH
CH3
COOPh
CH3
CH 3
H2C
(c)
(d)
H3C
CH3
PhOOC
COOPh
H2C
H3C
CH3
COOMe
(e)
(f)
H3C
COOH
O
O CH 3
Br
CH3
(g)
Br
(h)
Cl
Br
HO
H3C
CH3
O
(i)H3C
O
(j)
COOEt
COOEt
CH3
H3C
O
O
CH2
(k)
(l)
O
(m)
H2C
O
O
SO 3H
H3C
CH3
CH3
(n)
H3C
NCO
Nomenclature of Organic Compounds
RESPONSE TO SAQs
SAQ.III.1:
(i) pent-4-en-2-ol
(ii) 2-methylhex-3-ynoic acid
(iii) 5-hydroxyhexan-3-one
(iv)3-amino-2-bromo-5-chloroheptan-4-ol
(v) 2-methyl-5-oxopentanenitrile
(vi)2-methyl-3-sulfobutanoic acid
(vii) 7-tert-butoxy-6-formyl-3,5-dimethyl7-oxohept-4-enoic acid
(viii) 6-chloro-4-methyl-6-oxohex1-yne-3-sulfonic acid
(ix) 2-(prop-1-enyl)hexan-1-ol(new);
2-butylpent-3-en-1-ol(old)
(x) 3-aminopropane-1-thiol
(xi) 4-sulfanylbutan-2-ol (4-mercaptobutan-2-ol) (xii)7-(isopropylthio)octan-4-ol
(xiii) 4-(3-oxobutyl)hept-5-enoic
acid(old); 7-oxo-4-(prop-1-enyl)
octanoic acid(new)
(xiv)3-(3-ethyl-4-methylpentyl)
hept-4-en-2-one(old)
3-(but-1-enyl)-6-ethyl-7-methyloctan-2-one(new)
SAQ.III.2:
(i)5-cyano-3,4-dimethylpentanamide
(ii)3-methyl-5-oxopentanenitrile
SAQ.III.3:
(i) 4-ethynyl-2-methyl-5-(1-methylbut-1-enyl)undec-2-en-8-yne
(ii) 3-ethynyl-4-methyl-5-methylenehepta-1,6-diene
(iii) 3-ethynyl-4-isopropenyl-6-methyldeca-1,3,6-trien-8-yne(1-methylvinyl can be
used in place of isopropenyl)
(iv) 6-methyl-7-(1-methylethylidene)-4-vinylundeca-2,5,9-triene
(v) 6-ethyl-4-methylene-5-(prop-1-enyl)dodeca-7,9-dien-2-yne
SAQ.III.4:
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
(ix)
(x)
(xi)
(xii)
3-(2-amino-2-oxoethyl)-2,3-dimethylpentanediamide
3-(2-amino-2-oxoethyl)-6-oxohexanoic acid)
methyl 7-amino-2-(3-amino-3-oxopropyl)-7-oxoheptanoate
heptane-1,3,7-tricarboxamide
4-(aminocarbonyl)-7-oxoheptanoic acid
9-chloro-5-formyl-6-(methoxycarbonyl)-9-oxononanoic acid
propane-1,2,3-triol(glycerol)
2-methylnonane-3,5,7-trione
N,N’-dimethylbutane-1,4-diamine
pentane-1,1,3-tricarbaldehyde
3-(2-chloro-2-oxoethyl)hexanedioyl dichloride
5-ethyl 1-isopropyl 2-methylpentanedioate
(When two alkoxy(OR’) parts of diester are different, each alkyl group is prefixed with the
locant of carboxyl carbon to which the alkoxy group is attached)
SAQ.III.5:
CN
CH3
6
4
OHC
2
5
(i)H2C7
O
3
1
CH2
O
CH3
CHO
(ii)
OHC
CH2
OH
OH
O
H3C
7
CH2
8
(iii)
(iv)
H
OH
OH
H2N
2
3
1
O
1
O
H2N
4
3
2
CH3
CH3
NH2
5
(v)
5
H3C
OH
4
1
6
2
O
SAQ.III.6:
(i)
(ii)
(iii)
(iv)
3-formyl-4-hydroxy-2,2,5-trimethylhexanamide
N-tert-butylbutan-2-amine
2-isopropoxy-2-methylpropane
2,7,7,10-tetramethyl-6-oxoundec-8-ynal
SAQ.III.7:
(i)
(ii)
(iii)
(iv)
(v)
(v)
(vi)
(vii)
3-(6-methylcyclohex-1-enyl)propan-1-ol
3-[2-(aminocarbonyl)cyclohexyl]propanoic acid
4-(3-formylcyclopentyl)-2-methylbutanoic acid
1-cyclopentylethanol
2-(2,3-dimethylbutyl)cyclobutanol
3-(5-hydroxycyclohex-2-enyl)-2-methylpropanoic acid
2-(2,2-dimethylbutyl)cyclopropanamine
1-ethyl-2-propylcyclohexane
SAQ.III.8:
(i) ethylbenzene
(iii) propiophenone(1-phenylpropan-1-one)
(v) isopropylbenzoate
(vii) 1,2,3-trimethylbutylbenzene
(ii) isopropylbenzene(cumene)
(iv) ethoxybenzene
(vi) iodobenzene
SAQ III.9:
(i) (chloromethyl)benzene(Cl is not a functional group) (ii) 1-phenylmethanamine
(iii) methyl 2-phenylacetate
(iv) phenylacetonitrile(phenylethanenitrile)
(v) 2,3-dimethyl-3-phenylbutanal
Nomenclature of Organic Compounds
SAQ III.10:
3-methylaniline(m-toluidine), 1-chloro-2-nitrobenzene(o-nitrochlorobenzene),
3-sulfobenzoic acid, 1-chloro-4-ethylbenzene, 1,2-dinitrobenzene, 1,3-dichlorobenzene, 1-isopropyl
-2-nitrobenzene, 4-acetylbenzonitrile, 3-(aminocarbonyl)benzoyl chloride, 1,3-dinitrobenzene,
1-bromo-3-iodobenzene, benzene-1,3-dicarbaldehyde, benzene-1,2-dicarboxamide, ethyl 4cyanobenzoate, 1-ethyl-4-methylbenzene, 2,4-dichlorophenoxyacetic acid
SAQ III.11:
(i) 3-[2-(dimethylamino)phenyl]butanal
(iii) 3-(1-methyl-2-oxoethyl)benzonitrile
(v) 3-methyl-4-(2-nitrophenyl)but-2-enoic acid
(ii)2-(2-methylprop-1-enyl)aniline
(iv)2-(2-formylphenyl)propanoic acid
SAQ III.12:
methyl 2-methyl-5-nitrobenzoate, 3-acetyl-5-nitrobenzaldehyde, 4-ethyl-2-methyl-1nitrobenzene, dimethyl phthalate, 1-bromo-3-chloro-5-iodobenzene, 2-chloro-4-ethoxy-1methylbenzene, 3,4-dimethyl-2-nitroaniline, 1,2,4-trinitrobenzene, 2-chloro-5chlorocarbonylbenzoic acid
SAQ.III.13:
3-chloro-1-naphthol, 6-methyl-1-naphthamide, 4-methyl-9-anthrol, 9,10dichloroanthracene-1-carboxylic acid, 7-amino-2-naphthol
SAQ.III.14:
(i) bicyclo[1.1.1]pentane (ii)bicyclo[2.2.2]oct-2-ene (iii)7-methylbicyclo[4.2.1]non-3-ene
(iv)9-ethylbicyclo[3.3.2]decane (v)bicyclo[4.4.2]dodec-11-ene (vi) 8-methylbicyclo[5.2.0]non2-ene (vii)bicyclo[5.3.1]undec-4-en-2-amine (viii)5-aminobicyclo[4.2.1]non-2-ene-7-carboxylic acid
(ix)bicyclo[3.2.2]non-2-en-6-amine (x)bicyclo[3.1.1]hept-2-ene-6-carbaldehyde
SAQ III.15:
(i) 1,4-dimethylspiro[2.7]deca-5,8-diene
(iii) 4-methylspiro[2.2]pent-1-ene
(v) 4-methylspiro[4.8]trideca-1,7,9-triene
(ii) 6-isopropylspiro[3.5]non-1-ene
(iv)1-chloro-5-ethylspiro[3.3]heptane
SAQ III.16:
(i) 4-ethyl-2,5-dimethyl-3-oxahexane(3-isopropoxy-2-methylpentane)
(ii) 4-tert-butyl-3,5dimethyl-2-oxaheptane(3-tert-butyl-2-methoxy-4-methylhexane)
(iii) 3,3,5-trimethyl-4-oxaoctane([2-tert-pentoxypentane or 2-(1,1-dimethylpropoxy)pentane]
H3C
H
N
O
NH
SAQ III.17 : (i)
H3C
(ii)
CH3
(3-methy-4-(propylamino)pentan-2-one)
CH3
(piperidine)
ANSWER TO PRACTICE QUESTIONS
SET-I:
(a) 3,3-dimethylbutan-2-ol
(c) 1-chloro-2,3-dimethylpentane
(e) 3,4-dimethylpentan-2-one
(g) 2-ethyl-3,3-dimethylbutanal
(i) 3,3,4-trimethylpentanamide
(b) 4,4-dimethylpent-2-yne
(d) 3,4-dimethylpent-2-ene
(f) ethyl 2,3-dimethylpentanoate
(h) 2,2-dimethylpropanoyl chloride
(j) N-isopropyl-2-methylpropan-2-amine
SET-II:
(a) 2,3,4-trimethylpent-1-ene
(c) 2,2-dimethylpropan-1-amine
(e)2,2,3-trimethylbutanal
(g)2,2-dimethylpropanoic anhydride
(i)2,2,6-trimethylhept-3-yne
(b)2-methylpropan-2-ol
(d)methyl 2,2,3,3-tetramethylbutanoate
(f)isopropyl 2-methylbutanoate
(h)2-ethoxypropane
(j)2,2-dimethylpropanenitrile
SET-III:
(a)3-ethyl-4-methylheptan-2-one
(c)2,2-dimethylpentan-3-ol
(e)N-ethyl-N,2-dimethylpropan-1-amine
(g)4-ethyl-N-isopropyl-5-methylhexanamide
(i)ethyl formate(ethyl methanoate)
(k)methylthioethane(methylsulfanylethane)
(b)2-ethyl-3-isopropyl-4-methylhex1-ene(old);4-isopropyl-3-methyl5-methyleneheptane(new)
(d)calcium 2,2-dimethylpropanoate
(f)2,3,3,4,4-pentamethylpentanal
(h)4-bromo-2,2,3,5-tetramethylhexane
(j)2,2,3-trimethylbutanoyl bromide
(l)2,2,4-trimethylpentane-3-thiol
(m)1-isothiocyanato-2,2-dimethylpropane
SET-IV:
(The line structures are drawn. The readers are advised to convert these to structural
formula by attaching C and H atoms wherever required)
H 3C
3
(a)H
CH3
H 3C
CH3
1
2
3C
4
(b)H
OH
4
2
3C
5
3
CH3
CH3
4
(c)
H3C
CH3
CHO
1
CH3
H3C
2
N
3
COOH
5
1
(d)
2
H3C
CH3
CH3
1
CH3
3
O
O
1
3
(e)
H3C
4
2
CH3
Cl
(f)
1
H3C
3
2
CH3
O
CH3
Nomenclature of Organic Compounds
CH3
O
O
4
2
(g)H3C4
3
(h)H3C5
CH3
2
3
CH3
CH3
H3C
1
1
CH3
O
O
CH3
1
1
H 3C
(j)H3C
(i)
2
CH3
CH3
3
2
O
CH3
SET-V :
(a)5-(1,2,2-trimethylpropyl)nonane
(b)3,4-diethyl-2,6-dimethylheptane
(c)2-methylpropan-1-ol
(d)3,3-dimethylbutanal
(e)2-isopropyl-3,4-dimethylpentan-1-ol
(f)1-(tert-butoxy)but-2-ene
(g)tert-butyl 3-methylbutanoate
(h)5-ethyl-3-methyloctane
(i)2-methyl-3-methylenepentane[2-ethyl-3-methylbut-1-ene(old)]
SET-VI:
3
4
CHO
(a)
(b)
2
5
CH
1
H3C
6
2
4
6
(c)
NH2
1
2
3
3
5
H3C
1
(d)
7
CH3
OH
5
4
8
7
4
CH3
4
2
(e) O
(f)HOOC
1
1
5
3
6
6
3
COOH
8
5
7
CH3
2
O
CH3
H3C
CH3
3
CH3
4
CH3
(g)
2
4
3
H3C
(h)
CH3
6
2
1
5
8
6
7
5
CH3
1
2
H3C
4
3
6
8
5
7
1
CH3
1
(i)
10
9
CH3
11
3
H3C
2
(j)
H2N
CH3
NH2
O
O
O
NH2
2
3
1
5
4
6
7
(k) 3
CH3
(l)
1
1
OH
2
2
O
H3C
CH3
CH3
CH3
5
2
(m)
4
(n)H3C
3
H3C
1
CH3
SCN
CH3
Set-VII:
(a) 3-chloro-2,5-dimethylheptan-4-one
(b) 4-hydroxy-5-methylhept-2-en6-ynoyl chloride
(c) 3-ethyl-3,5-dihydroxypentanamide
(d) 2-amino-4,4-dimethylpentanoic acid
(e) 3-bromo-N-ethyl-3-methylpentanamide
(f) 3-(1-hydroxyethyl)-5-methylheptanal
(g) 3-hydroxy-4-methylpent-4-enal
(h) 3-amino-5-ethylphenol
(i) 2-ethyl-4-(ethylamino)-2-methylbutanal
(j) 3,6,9-trimethyldeca-2,4,6,8-tetraenoic acid
(k) 4-chloro-2-ethylcyclopentanone
(l) 5-amino-2-methylcyclohex-2-en-1-one
(m) 5-(1-methylethylidene)deca-1,6-dien-8-yne (n) 3-(1-hydroxy-1-methylethyl)heptane[5-isopropylidenedeca-1,6-dien-8-yne]
1,5-diol
(o)2-methylpentan-3-one
SET VIII:
O
EtOOC
1
CH3
(a)
2
CH3
3
1
2
4
3
(b)
CH3
O
COOH
3
H3C
CH3
1
CH3
5
(c)
(d)
4
2
O
CH3
Cl
O
H3C
(e)
O
4
3
2
COOH
(f)H3C
N
CH3
1
Ph
Nomenclature of Organic Compounds
O
1
Br
(g)
8
H3C
Br
6
4
7
6
Br
(h) 5
2
5
3
2
3
CN
9
4
1
CH3
+
CH(CH3) 2
O
Cl
(CH3)2CH N CH(CH3) 2
(i)
CH2
-
(j)
CH(CH3) 2
EtOOC
COOEt
CH3
(k)
5
CH2
2
1
6
(l)
O
3
4
H3C
O
O
CH3
CH3
i-Pr
CH3
CHO
CN
O
CH3
H3C
(m)
CH3
(n)OHC
COOH
OH
CH3
SET IX :
(a) 4-methylhex-3-yne
(c) 5-oxopentanoic acid
(e) N,2,3,3-tetramethylbutan-1-amine
(g) 1-chloro-1-methylpropyl 4methylpent-2-enoate
(i) 1-nitro-4-vinylbenzene
(k) isobutyl 5-(isopropylamino)-4
-methylpentanoate
(m) octa-3,5-diynedioic acid
(o) 1-methylcyclohexa-1,3-diene
(b) isobutoxymethylbenzene(since ether
group does not have any precedence
as functional group, the compound
is named as aromatic)
(d) cyclopropylacetyl chloride
(f) chloromethylcyclohexane
(h) 4-bromo-2,6,6-trimethylhept-4-enoic acid
(j) 6-methylcycloocta-1,4-diene
(l) 5-cyano-2,3-dimethylpent-3-enamide
(n) isopropoxycyclopentane
(p)2-isocyano-3-methylbutane
SET-X:
CH3
CH3
(a)
H3C
CH3
CH3
HO
CH3
O
(b)
3
H3C
CH3
4
CH3
1
2
O
CH3
OH
O
1
1
6
2
6
2
CH3
5
3
5
3
2
3
(c)
4
H3C
(d)
Ph
4
1
H3C
CH3
CH3
CH3
H3C
NH2
CH3
(e)
O
(f)
NO2
CH3
H3C
CH3
4
(g)
(h)
2
NH
3
H3C
CH3
1
5
O
CH3
CH3
CN
7
(i)
5
6
H3C
4
1
H 3C
3
2
CH2
1
2
8
5
(j)H C
3
2
6
3
CH3
4
COOH
1
7
CH 3
8
(5-sec-butyl-6-cyanolhept-5-en-3-ynoic acid)
Br
O
OH
3
2
4
1
(l)
(k)
OH
CH3
CH3
SET-XI:
(a)5-chloro-7-methylocta-2,4,6-trienoic acid
(c)4,4-dimethyl-3-phenylpentan-2-one
(e)ethyl 6-ethyl-2-methoxycyclohex-3ene-1-carboxylate
(g)3-(3-chlorophenyl)-1,2diphenylprop-2-en-1-one
(i)2-ethyl-3-iodo-6-methylcyclohexanone
(k)cyclopropanecarboxylic
propanoic anhydride
(m) cyclohex-3-ene-1,2-dicarboxylic acid
(o)sodium butane-2-thiolate
(b)5-tert-butyl-8-methylnonane-3,5-diol
(d)1,5-diaminopentan-2-ol
(f)2-isopropoxypentan-3-ol
(h)3-tert-butyl-2,2,4,4-tetramethylpentane
(j)4-chloro-5-hydroxypentan-2-one
(l)cyclohexyl 2,2-dimethylpropanoate
(n)sodium propan-1-olate
(p)1-ethyl-2-methylpropyl cyanate
SET-XII:
O
(a)H3C
O
CH3
(b)
H3C
2
4
6
Ph
5
NH2
3
1
NH2
O
7
Nomenclature of Organic Compounds
Cl
CH3
3
H3C
(c)
(d)
4
1
N
2
4
CH3
2
H 3C
3
H2N
3
HO
COOH
1
5
2
1
4
(e)
Ph
COOH
2
H3C
O
(f)Ph
CH3
Ph
1
3
OH
O
CH3
3
5
6
4
2
(g)H C
1
6
O
(h)
3
1
5
CH3
H3C
CH3
2
3
O
4
CN
O
OH
H3C
CH3
I
(i)
(j)
CH 3
CH 3
(k)
(l)CH3CH2SK
CH3
SET-XIII:
(a)glycerol(propane-1,2,3-triol
(c)1,2-dichloroethane
(e)oxalic acid(ethanedioic acid)
(g)but-2-enal
(i) 1-chloro-4-(chloromethyl)-5methylhexan-2-one
(k)3-bromo-2-chloro-5-methyloctane
(m)2-methylhex-4-yn-3-ol
(o)3-oxobutanoic acid
(q)4-methyl-5-oxopent-2-enoyl chloride
(s)sec-butyl 2-methyl-3-phenylpropanoate
(u)4-isopropyl-2,3-dimethylhexa-1,5-diene
(w)ethane-1,1,2-tricarbaldehyde
(y)2-amino-5-sec-butoxy-4-methylhex3-enenitrile
(b)3-bromo-3-methylbutanoic acid
(d)2,2,3-trichlorobutan-1-ol
(f)4-bromopent-2-ene
(h)pentane-2,4-dione
(j)3-bromopenta-1,2,4-triene
(l)1-chloro-4-methylpent-3-en-2-one
(n)isopropyl 4-methoxypent-2-enoate
(p)hexanedioic acid
(r)4-hydroxy-3-methylpentan-2-one
(t)3-chloro-4-cyclopropylbutan-1-amine
(v)2-chloro-2-cyclohexylethanol
(x)N-isopropyl-3,3-dimethylbutan-2-amine
(z)6-hydroxycyclohex-2ene-1-carboxylic acid
SET-XIV:
(a)
(b)
(c)
(d)
(e)
9-(dimethylamino)-5-(3-ethoxy-3-oxopropyl)-8-(hydroxymethyl)-6-(prop-1enyl)dec-7-enoic acid
7-methyl-6-oxooct-4-en-2-ynedioic acid (lowest set of locants for the functional group)
3,9-dimethylbicyclo[4.3.1]decane
4-methylbicyclo[2.2.2]oct-1-ene
ethyl 2-oxocyclopentanecarboxylate
(f)
(g)
(h)
(i)
(j)
(k)
(l)
(m)
(n)
(o)
SET XV:
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
(ix)
(x)
(xi)
(xii)
(xiii)
(xiv)
(xv)
2-(ethoxycarbonyl)cyclopentanecarboxylic acid
4-(isopropylamino)-2-methylcyclohexanol
spiro[2.2]pentane
4-hydroxy-2-isopropylbenzaldehyde
ethyl 3-amino-5-vinylbenzoate
butan-1-imine (=NH group is called imine group)
N-isopropyl-N,2-dimethylpropanamide
5-amino-2-methylphenol
2-(4-ethylphenyl)ethanamine
3-sec-butyl-1,1-dimethylcyclopentane
4-(but-2-enyl)octa-1,3,6-triene(old),5-(prop-2-enylidene)nona-2,7-diene
4-(pent-3-enyl)octa-5,7-dienoic acid(old); 4-(buta-1,3-dienyl)non-7-enoic acid
N,2-dimethyl-3-methylenehex-5-enamide
4-(but-2-enylidene]-2-ethylnona-5,7-dien-1-ol
(1,3-dichloropentyl)benzene
1-bromo-4-ethyl-2-nitrobenzene
2-aminocyclobutanol
N,N-diethylbut-3-en-2-amine
2,2-dimethyl-4,5-dioxopentanoic acid
N-(1,2,3,4-tetramethylpentyl)hexan-1-amine
cyclohex-2-en-1-ol
hex-4-en-1-yne
3-(2-oxoethyl)hexanedial [ 3-(formylmethyl)hexanedial]
3-(cyclopenta-1,4-dien-1-yloxy)propan-1-ol
1,7,7-trimethylbicyclo[2.2.1]heptan-2-one
SET XVI:
(a) 3-ethyl-5-methylheptane
(c)7-ethylidene-3-methyl-5-(1-methylprop2-enyl)-6-vinylundeca-2,4,8-triene
(e)4-(2-methoxy-2-oxoethyl)heptanoic acid
(b)4-methylhex-1-en-5-yne
(d)diphenyl 2-methyl-4-(2-oxo-2phenoxyethyl)heptanedioate
(f)1-methoxy-4-methylbenzene
(p-methylanisole)
(g)3-methoxycyclopentene
(h)1,3,5-tribromo-2-chlorobenzene
(i)ethyl 5-ethyl-4-(2- hydroxyvinyl)-6-methyl-2-(1-methylprop-1-enyloxy)heptanoate(new);
ethyl 4-(1-ethyl-2-methypropyl)-6-hydroxy-2-(1-methylprop-1-enyloxy)hex-5-enoate(old)
(j)ethyl 2-oxocyclopentanecarboxylate (k)3-methylbicyclo[2.2.2]octane-2,6-dione
(l)3-(buta-1,3-dienyl)-6-methyleneoctane-1-sulfonic acid(new);
3-(3-methylenepentyl)hepta-4,6-diene-1-sulfonic acid(old)
(m)2,2-dimethylpropanoic 2-ethyl-3,3-dimethylbutanoic anhydride
(n)1-isocyanato-3-methylbutane