NOMENCLATURE of organic compound pharm D poc

NOMENCLATURE OF AN ORGANIC COMPOUND
By
Pharmaceutical Organic Chemistry – Nomenclature of an Organic Compound – G. Rousso
G.Rousso , M. Pharm.,
Associate Professor,
SPS, VISTAS

 Organic chemistry is the major branch of chemistry that deals with the scientific study
of preparation, structure, properties, composition, and reactions of carbon-
containing compounds.
 Almost all organic compounds contain at least one carbon-hydrogen bond (C-H) in it.
 Organic compounds are now defined as “compounds that contain carbon”. Then the
next question arises “Why is an entire branch of organic chemistry devoted to the study
of carbon-containing compounds?
 The so-called organic compounds have been found to be mainly compounds of carbon
and hydrogen (called hydrocarbons) and their derivatives.
 Finally, organic chemistry is defined today as “The chemistry
of hydrocarbons and their derivatives”. There is no sharp line of demarcation between
organic and inorganic chemistry, the difference between organic and inorganic
compounds is still being retained as a matter of convenience than of principle.
ORGANIC CHEMISTRY

NON-SYSTEMIC NOMENCLATURE
 In the early days, scientists named the compounds based on historic background. These
are called common names or trivial names.
 Example:
Wood spirit: It was obtained from the distillation of wood. Later it was named
methanol based on Greek words (methu: wine and hale: wood).
Acetic acid: It is the major constituent of vinegar. (Latin; acetum = vinegar).
 As the number of compounds were discovered more, naming by history becomes
difficult.
 Hence systematic naming becomes important.
NOMENCLATURE OF ORGANIC COMPOUNDS

The
systematization of
names was carried
out by the
International
congress of leading
chemistry held in
Geneva, 1892.
A rational system of
nomenclature was
formed and it is called
as Geneva system of
nomenclature. Slight
revision and
improvements were
carried out from time
to time.
One such was held
at Liege (Belgium)
in 1930 by the
International Union
of Chemistry and it
is called as IUC
system of
nomenclature.
The IUC was later
modified by the
International Union
of Pure and Applied
Chemistry in 1958
and it is called as
IUPAC system of
nomenclature.
NOMENCLATURE OF ORGANIC COMPOUNDS
SYSTEMIC NOMENCLATURE
 To name the organic compound according to IUPAC nomenclature a set of rules were framed and all
the compounds are named accordingly.
 However, even today some of the common names are used for organic compounds.
 Hence the chemists should also be aware of the common names apart from IUPAC nomenclature.

 IUPAC nomenclature is been used now a days to name organic compounds.
 However, some of the simple compounds are named by trivial names.
 Earlier names have been continued even today but a complex organic compound can be
given using IUPAC nomenclature only.
 Various rules are followed for naming compounds by the IUPAC system.
 Rule 1: Longest chain rule
 Rule 2: Lowest number for substituents rule
 Rule 3: Arrangement of prefixes
 Rule 4: Lowest number for functional group
 Rule 5: Writing names for compounds containing more than one functional group
 Rule 6: Treatment of “like things alike”
 Rule 7: Functional groups and the selected chain
IUPAC NOMENCLATURE

 In the given organic compound longest possible chain of carbon atoms is selected and
the compound is named as a derivative of this alkane.
 Example:
1. LONGEST CHAIN RULE

The given compound has five
carbons in horizontal line and
six carbons in the longest chain
hence we should select it as a
hexane derivative only.
1. LONGEST CHAIN RULE

 After selecting the longest chain, the numbering should be given from one end to the
other end.
 While giving the number, the substituents should be given the lowest possible number.
 Example:
2. LOWEST NUMBER FOR SUBSTITUENTS RULE

In the first case, naming 4,7-
dimethyl octane is not
correct because 2,5-
dimethyl octane have the
lowest numbers for the
substituents.

 If different alkyl groups are in equivalent positions in relation to the end of the chain,
preference is given to the end where the radical has fewer carbon atoms (methyl, ethyl,
etc).
 Example:

The second case of naming is correct because the methyl group is given preference over
the ethyl group.

 If identical radicals are at equal distance in the chain then the numbering starts from the
end where it is more branched.
 Example:

The second way of
naming is correct where
the branching end is
given preference.

 If two sets of numbers are possible for the given chain, then the order of prefixes in
the name will decide the numbering (alphabetical order of the substituents).
 Example:

The given compound can be named 1-bromo-4-chloro butane or 1-chloro-4-bromo butane.
As the prefix bromo is first, the second name is correct.

 If chains of equal length are competing for selection as the parent chain in a branched
alkane, the preference goes to the chain carrying more branches.
 Example:

In the given organic compound second
way of naming i.e., 3-ethyl-2,6-
dimethyl heptane is correct as it has
three branches where as 5-isopropyl-
2-methyl heptane is wrong as it has
only two branches.

 When there is more than one group attached in the chain, they should be arranged
alphabetically.
 If same group is presented in two or three places of chain then the prefix di or tri etc are
used.
 Example:
3. ARRANGEMENT OF PREFIXES

The given organic compound is
named as 5-ethyl-2,3-dimethyl
heptane as per alphabetical
order.
3. ARRANGEMENT OF PREFIXES

 When the functional group is present in the chain, it should be given first preference
even if it violates lowest number rule 2.
 Double bond or triple bond also considered as functional groups.
 Example:
4. LOWEST NUMBER FOR FUNCTIONAL GROUP

The order of preference of numbering
is as follows.
 To the principal functional
group of a compound.
 To the double or triple bond.
 To the substituent atoms or
groups.

 When more than one functional group present in the compound, then the order of
preference is as follows.
 Carboxylic acids (R-COOH)
 Carboxylic acid derivatives (R-COX)
 Aldehydes (R-CHO)
 Nitriles (R-CN)
 Ketones (R-CO-R’)
 Alcohols (R-OH)
 Amines (R-NH2)
 Ethers (R-O-R’)
 Olefins (=)
 Acetylenes (=)

 Systematic name for allyl alcohol is
 For nomenclature purposes the following functional groups are considered as
substituents not as functional groups (halo, nitroso, and azo as they do not have
ending).
 When there is more than one functional group in the compound, one is the principal
functional group and the other is the secondary functional group.

GROUPS CITED ONLY AS PREFIXES

GROUPS CITED ONLY AS PREFIXES (or) SUFFIXES

 Whenever more than one functional group is present in the given compound then the
ending is suitably modified.
 Carbon – carbon multiple bonds and second functional groups are combined in endings
or the important functional group is considered as a substituent.
 Example:
5. WRITING NAMES FOR COMPOUNDS CONTAINING MORE
THAN ONE FUNCTIONAL GROUP

NOMENCLATURE OF SOME SIMPLE POLYFUNCTIONAL COMPOUNDS

NOMENCLATURE OF SOME UNSATURATED COMPOUNDS OF
SIMPLE FUNCTIONS

NOMENCLATURE OF SOME COMPOUNDS OF COMPLEX
FUNCTIONS

 All groups of one kind which occur in a single molecule should be given the same
treatment as far as possible.
 Example:
6. TREATMENT OF “LIKE THINGS ALIKE”

In the given example carboxylic acid is
the main functional group, the parent
compound should include two or
three functional groups as possible.
6. TREATMENT OF “LIKE THINGS ALIKE”

 The maximum number of functional groups must be included in the carbon chain even
if it violates the longest chain rule (Rule 1).
 Example:
7. FUNCTIONAL GROUPS AND THE SELECTED CHAIN

 When there is a side chain with a side chain, the latter is numbered and the name of the
complex is considered to start with the first letter of its complete name.
 Example:
7. FUNCTIONAL GROUPS AND THE SELECTED CHAIN

 Step 1: Locate the longest chain containing principal functional group and as many
as a secondary functional group and carbon-carbon multiple bonds.
 Step 2: Select the root word corresponding to the chain length. For example Hex for six
carbon atom chains.
 Step 3: Number the longest chain selected from the end near the principal functional
group.
 Step 4: Based on the carbon-carbon bonds attach the suffix -ane, -ene or yne
respectively to the root word of the carbon chain.
 Step 5: Add suitable prefixes and suffixes with numerals to indicate the number and
position of each side chain, substituent, or functional group.
STEPS INVOLVED IN WRITING IUPAC NAME OF THE COMPOUND

STEPS INVOLVED IN WRITING IUPAC NAME OF THE COMPOUND

 Position of numerals used in the enumeration of substituents: Numerals representing the
location of unsaturation or functional groups are placed before the name stem as
 2-Pentene not pentene-2
 1-Chloro-2-pentene not 1-chloropentene-2
 1-hexene-3-yne Not hexenyne-3
 Writing names: The names of radicals replacing hydrogen atoms in compounds are carried out.
Example: Chlorotoluene (chlorine replaced “H” atom of toluene).
 Elision of vowels: To avoid ambiguity vowels, whether pronounced or silent are generally
retained in systematic naming. This results in using double vowels. Example: Cyclooctane
 However it has been accepted to elide the following vowel a, e, and o in the following
circumstances.
 When preceding the suffix name of a functional group. Example: Propanol not
propaneol; Hexamine not hexane amine.
 Naming Alkenes and Alkynes on the same compound. Example: Pentenyne not
penteneyne.
POINTS TO BE REMEMBER

 Punctuation marks: Most commonly used punctuation in naming organic compounds
are hyphens, commas, and enclosing brackets.
 Hyphens:
Used to connect numbers and letters serving as locants. Example:
2-Chloropropanone; 1-Bromo-3-chlorobutane.
Used to connect the prefixes like cis, trans (configurational prefixes) or structural
prefixes (sec, tert, neo) with the compound name. Example: Cis-2-butene, tert–butyl
alcohol.
The prefixes cis, trans, iso, neo, tert, etc should be in italics.
 Commas: Used to separate individual members of a series of locants. Example: 1,1,2-
Trichloro propane.
 Enclosing brackets: Parenthesis ( ) and square [ ] are used as demarcation symbols
when the locants are related to complete names. Example: 4-Amino-N-(hydroxyl
ethyl)butyramide.
POINTS TO BE REMEMBER

To write the chemical structure of a given compound from the IUPAC name, the following
steps are to be adopted.
 Locate the parent alkane: From the name write the number of carbon atoms of the
alkane in a straight chain and number them from any one of the ends.
 Locate the suffix: Locating suffix gives information about chain length, nature of
functional group along positions.
 Locate the groups/substituents: As mentioned in prefix locates the groups position in
the chain.
 Add hydrogen atoms if required to satisfy: Four valencies of each carbon atom to get
the formula.
WRITING THE STRUCTURAL FORMULA FROM THE GIVEN IUPAC NAME

3-ethyl-2,5-dimethyl-1,4-octadiene
 Parent alkane is octane. Write eight carbon atoms in a straight chain and number it.
 The suffix diene indicates two double bonds in 1 and 4 points.
 To locate the groups mentioned in prefix we attach ethyl group on 3rd C and methyl
groups to 2nd C and 5th C to get the desired compounds.
 Finally to satisfy valencies hydrogen atoms are added.
WRITING THE STRUCTURAL FORMULA FROM THE GIVEN IUPAC NAME

Alkanes are the simple aliphatic organic saturated hydrocarbons, having the general
formula CnH2n + 2 where, n = 1, 2, 3 etc.
Carbon and hydrogen are connected to each other by a single covalent (sigma) bond.
They do not contain π bond in their structure and the 4 valency of carbon atom is
saturated by carbon-hydrogen (C-H) and carbon–carbon (C-C) bonds and hence they are
called as “saturated hydrocarbons”.
As alkanes contain strong C-C and C-H bonds, they do not react with variety of reagents
at normal conditions therefore they are also called as paraffins (The term derived from
Latin words parum = little and affins = affinity i.e., Less affinity towards any reagent).
All members of alkanes differ from each other by their molecular formula by the unit of -
CH2- and are called as members of “homologues series”.
Removal of one hydrogen from alkane yields alkyl group (–R).
General formula for alkyl group is CnH2n + 1.
ALKANES

Alkanes can be named by three systems.
 Common name system or Trivial system
 Substituted methane system
 IUPAC name system
NOMENCLATURE OF ALKANES

 This system of naming is based on branching in alkanes.
 The parent name of isomeric alkanes is same and the prefix distinguishes the each isomer
based on branching.
 The prefix ‘n’ (means normal) used for alkanes in which all carbon atoms is in
continuous chain. Example: n-Butane, n-Pentane.
 The prefix ‘iso’ used for alkanes in which one methyl group branching is present.
Example: isoButane, iso-Pentane.
COMMON NAME SYSTEM OR TRIVIAL SYSTEM

 The prefix ‘neo’ used for alkanes in which two methyl groups are branched in same
carbon atom e.g. ‘neo’-Hexane.
 The first four alkanes are known by their common names (which are derived from
history).
 Fifth member onwards are derived from Latin or Greek numerals which indicate the
number of carbon atoms in a molecule.
 Alkyl groups: An alkyl group is obtained by removing one hydrogen atom from alkane.
 Their name is derived from the alkane by removing -ane from concerned alkane and
adding -yl (Alkane-ane +yl = Alkyl) to the corresponding alkane.

 Types of alkyl groups: Based on the structural formula, alkyl groups are classified into
primary, secondary and tertiary carbon

 The most highly branched carbon atom is considered as the parent and the alkyl groups
attached to this carbon atom are named in alphabetical order.
SUBSTITUTED METHANE SYSTEM

 To overcome the limitation of earlier methods, IUPAC system of naming organic
compounds was initiated.
 In this system some of the common names also retained.
 The steps involved in the IUPAC nomenclature are described herewith examples.
Step 1 (Select the longest chain)
 The longest continuous carbon chain is selected to give the parent name.
 The longest continuous chain has four carbon atoms i.e., Butane
IUPAC NAME SYSTEM

Step 2 (Number the longest chain)
 The carbon atoms in the longest chain are numbered.
 The numbering should be given in such a way that the carbon atom containing
substituent will get lowest number.
 The branched carbon gets lower number in first case, hence it is correct.
Step 3 (Locate and name the substituents)
 Mark the position and name of each substituent in the carbon chain.
 Attached group is methyl and attached at 2nd position of the carbon chain.
IUPAC NAME SYSTEM

Step 4 (Name the compound by combining longest chain and substituents)
 The position and the substituents are combined with the longest chain and the name is
written as one word.
 Longest chain is butane and the methyl group is attached at 2nd position. Hence the
IUPAC name of the above compound is 2-methylbutane.
 Indicate the number of groups present and their position:
If same substituent is present more than once then it is indicated by adding prefix -di,
-tri, -tetra etc.
If more than one type of substituents is present, then arrange the substituents in
alphabetical order.
IUPAC NAME SYSTEM

Trivial names of the following branched alkanes have been recognized in 1957 IUPAC
rules.
IUPAC NAME SYSTEM

Isomerism in alkanes
n-Alkanes when heated they are converted into their branched chain isomers is called as
isomerisation.
As there is higher possibility of different arrangements of carbon atoms in compounds
containing more than three carbons, they exhibit wide structural isomerism especially of
chain isomerism.
First three members of hydrocarbon series i.e., methane, ethane and propane do not
exhibit any isomerism.
Butane exhibits 2 isomers, Pentane 3 isomers, Hexane 5 isomers, Heptane 9 isomers,
Octane 18 isomers, and Decane 75 isomers.
IUPAC NAME SYSTEM

IUPAC NAME SYSTEM

The unsaturated hydrocarbons which contain at least one carbon-carbon double bond
[C=C] are known as alkenes.
They are also named olefins, because of the fact that lower members form oily products
upon reaction with halogens and halogen acids.
They have the general formula CnH2n where, n = 1, 2, 3….
In contrast to alkanes (general formula CnH2n+2)) they have two hydrogens atoms less
and hence the tetravalency of carbon is satisfied by presence of carbon-carbon double
bond [C=C].
First member of alkenes is ethylene. Alkenes occur free in nature but large quantities of
alkenes are obtained during cracking of petroleum.
The carbon-carbon double bond between adjacent carbon atoms in alkenes is made up of
one σ bond and one π bond.
Because of the presence of more exposed π electrons, alkenes are more reactive than
alkanes which have only σ bonds.
ALKENES

This method is used to name only first four members by replacing the suffix
-ane from alkane with – ylene.
The symbols α and β used to indicate the position of double bonds.
α indicates the double bond in first carbon and β in second carbon.
Some scientists still use another Greek letter (Δ) to indicate the position of double bond.
 The number placed at the right hand corner of the symbol (Δ) indicates the position of
double bond.
1. COMMON NAME SYSTEM

In this method alkenes are named as derivatives of ethylene.
Dialkyl derivatives exhibit isomerism.
The isomers are named as symmetrical or asymmetrical.
If the alkyl groups attached to two different carbon atoms, then it is called as symmetrical
(sym or s).
If they are attached with same carbon atom they are called as asymmetrical or
unsymmetrical (unsym or as).
2. ANOTHER COMMON NAME SYSTEM

The name of the hydrocarbon is based on the parent alkane having longest chain in which
one double bond is present then the suffix - ane of alkane is replaced with -ene.
The hydrocarbon chain is numbered from the end near the double bond and the position
of double bond is indicated by mentioning the number of that carbon atom.
Name of the parent hydrocarbon is chosen and the position of double bond is placed
before that. Then the location and name of the substituent are prefixed.
3. IUPAC NAME SYSTEM

When more than one double bond is present then the suffix –ene of alkene is replaced
with – diene or – triene for two or three bonds respectively along with the position of the
double bonds.
Alkenyl groups: The monovalent groups formed by removing hydrogen from alkene are
called as alkenyl group. For example

 Hydrocarbons with two carbon-carbon double bonds are called as dienes or alkadienes.
 The general formula is CnH2n-2 (similar to alkynes). For example:
ALKADIENES or DIENES or DIOLEFINS

 The IUPAC system of naming dienes is similar to alkenes.
 Based on the carbon chain length the suffix –ene of alkene is replaced by –adiene.
 The position of two double bonds is indicated by giving least number to one of the
double bond and the other get next minimum number. For example
ALKADIENES IUPAC NAME

 Alkynes are organic molecules made of the functional group carbon-carbon triple bonds
and are written in the empirical formula of CnH2n−2.
 They are unsaturated hydrocarbons.
 Like alkenes have the suffix –ene, alkynes use the ending –yne; this suffix is used when
there is only one alkyne in the molecule.
ALKYNES

ALKYNES
The name of the hydrocarbon is based on the parent alkane having longest chain in which
one triple bond is present then the suffix - ane of alkane is replaced with -yne.
The hydrocarbon chain is numbered from the end near the triple bond and the position of
triple bond is indicated by mentioning the number of that carbon atom.
Name of the parent hydrocarbon is chosen and the position of triple bond is placed before
that. Then the location and name of the substituent are prefixed.
C C
CH3
1 2 3 4 5
CH CH3
CH3
4-Methyl-2-pentyne
C C
C
H
1
2
3 4 5
CH CH3
CH3
CH3
CH3
6
2,5-Dimethyl-3-hexyne
C CH 2-Pentyne
H2
C
H2
C
H3C
1
2
3
4
5
C CH Butyne
H2
C
H3C

When more than one triple bond is present then the suffix –yne of alkene is replaced with
– diyne or – triyne for two or three bonds respectively along with the position of the
double bonds.
Alkynyl groups: The monovalent groups formed by removing hydrogen from alkyne are
called as alkynyl group. For example
CH3 C C C C CH3
2,4-Hexadiyne
CH C C C C CH3
1,2,4-Hexatriyne
1 2 3 4 5 6
1 2 3 4 5 6
CH C
1
2
3
CH C
H2
C
Ethynyl
2-Propynyl

 Alcohols are hydroxy (-OH) derivative of saturated hydrocarbons in which one or more
hydrogens are replaced by hydroxyl groups.
 The general formula for a simple alicyclic alcohol is CnH2n+1OH.
 If the hydrocarbon contains one hydroxyl group, then it is called monohydric alcohols, if
it contains two, three or more it is called as dihydric, trihydric or polyhydric alcohols
respectively.
 If the carbon atom is attached with more than one –OH group it becomes unstable,
hence hydroxyl groups are always attached to different carbon atoms.
ALCOHOLS

COMMON OR TRIVIAL NAME SYSTEM
 Alcohols are named as alkyl alcohols i.e., the prefix alkyl indicates the name of the alkyl
group which is followed by word alcohol.
 For example, -C2H5-OH (ethyl alcohol). In the higher alcohols, the nature of alcohol i.e.,
1o
, 2o
, 3o
is indicated as a prefix to the name of alcohol.
CARBINOL NAME SYSTEM
 In this method, all alcohols are considered as derivatives of carbinol (methanol). The
alkyl groups attached are indicated in alphabetical order
ALCOHOLS

 In this system alcohols are named as derivatives of alkanes, the suffix -e is replaced with
-ol. i.e., alkanol.
 The rules are
 The longest carbon chain containing –OH is taken as parent chain.
 Name is derived by replacing the suffix –e of the corresponding alkane with -ol.
 Number the carbon chain in such a way the –OH group should get lowest possible
number.
 Indicate the other substitutes, or multiple bonds by numbers.
IUPAC SYSTEM

 Aldehydes and ketones are carbonyl compounds which possess carbonyl (C=O) group in
their structure.
 If the carbonyl group is attached to a primary carbon atom it is called an aldehyde
(except formaldehyde which is attached to hydrogen) and if it is attached to a secondary
carbon atom, it is called ketone.
 Both the aldehydes and ketones possess the general formula CnH2nO.
 The functional group of aldehyde is CHO which is present in the end of chain while the
functional group of ketone is C=O which is not present in the end of chain but is joined
to a carbon atom on either side.
ALDEHYDES & KETONES

 The simplest carbonyl compound is an aldehyde i.e. formaldehyde in which a carbonyl
group is bonded to two hydrogen atoms.
 In all other aldehydes, the carbonyl group is attached to hydrogen and to an alkyl or aryl
group.
 Ketones and aldehydes are similar in structure and physical properties.
 But they differ in their chemical properties especially with nucleophiles and oxidizing
agents.
 Aldehydes are more reactive than ketones.
 Common carbonyl compounds are as follows
ALDEHYDES & KETONES

COMMON NAME SYSTEM
 Based on the corresponding carboxylic acid obtained from aldehydes, the names are
given. The name of aldehyde is derived by replacing –ic acid of the acid with –ldehyde.
 For example, the name formaldehyde is derived from formic acid.
 The substituents present in the chain are indicated by the Greek letters α, β, γ etc.
 The carbon atom next to aldehyde group is called as α-carbon and next one is β and so
on.
NOMENCLATURE OF ALDEHYDES

IUPAC NAME SYSTEM
 It is derived by replacing the –e of alkane with –al.
 The aldehyde function is always present in the end.
 When numbering is given to the chain, the carbonyl carbon gets number 1.
NOMENCLATURE OF ALDEHYDES

COMMON NAME SYSTEM
 In this method, they are named by adding the word ketone along with the name of two
alkyl groups attached to the carbonyl group.
 When same alkyl groups are present then it is named as dialkyl ketone example,
dimethyl ketone (acetone), otherwise the name of individual alkyl group is mentioned
and then the word ketone is to be added in suffix. For example
NOMENCLATURE OF KETONES

IUPAC NAME SYSTEM
 In this method, ketones are named by replacing –e of corresponding alkane with –one.
 While numbering the carbon chain, carbonyl group should be given the lowest possible
number and this number is used to indicate the position of carbonyl group in the carbon
chain as in the following example.
NOMENCLATURE OF KETONES

COMMON NAME AND IUPAC NAME OF SOME ALDEHYDES AND KETONES

 These are the carboxyl derivatives of hydrocarbons in which one or more hydrogen
atoms are replaced with one or more carboxyl (–COOH) groups as in the following
examples.
 Carboxylic acid containing one – COOH group is known as mono carboxylic acids while
others having two or three – COOH groups are known as di and tri-carboxylic acids
respectively.
 The carboxyl group consists of a carbonyl group attached to a hydroxyl group and
therefore named as carboxyl.
CARBOXYLIC ACIDS

1. COMMON NAME SYSTEM
 Based on the sources of their origin their name is derived from the Greek or Latin words.
 They follow the suffix –ic acid only.
 In this system, Greek letters α, β and γ etc are used to indicate the position of
substituents.
 The carbon atom adjacent to –COOH group is named as α and the next carbon atom is β
and so on.
CARBOXYLIC ACIDS

2. DERIVED NAME SYSTEM
In this method, the carboxylic acids are named as derivatives of acetic acid.
CARBOXYLIC ACIDS

 In this system, the name of individual acid is derived by replacing the end – e of alkane
with –oic acid.
 For example the name pentanoic acid is derived from pentane.
 While naming the higher acids, the longest chain with –COOH group is selected and
numbered by starting with 1 (one) for the carbon of –COOH group and the position of
substituents are indicated.
CARBOXYLIC ACIDS

CARBOXYLIC ACIDS

The amide functional group has an nitrogen atom attached to a carbonyl carbon atom.
If the two remaining bonds on the nitrogen atom are attached to hydrogen atoms,
the compound is a simple amide.
If one or both of the two remaining bonds on the atom are attached to alkyl or aryl
groups, the compound is a substituted amide.
AMIDES

AMIDES

 Amides are derivatives of carboxylic acids and if you have already read about
the nomenclature of carboxylic acids, you are familiar with suffixes -ic acid, -oic acid.
 Now, for primary amides, all you need to do is replace the -ic acid, or -oic acid ending
with the suffix “amide”.
AMIDES

 All the substituents are numbered by starting from the amide carbon (unless a higher
priority group is present) and placed alphabetically just like for naming any other
functional group.
 When the amide group is connected to a ring, the suffix “carboxylic acid” is replaced
with “carboxamide”. (Notice that the amide carbon, in this case, is not counted as part
of the parent chain).
AMIDES

 Secondary and tertiary amides bear alkyl group(s) on the nitrogen and just like other
substituents, these are placed at the beginning of the name.
 However, these alkyl groups are also specifically indicated with the letter “N ”.
 For example, N-methyl, N-ethyl, or N-ethyl, N-propyl if two alkyl groups are connected:
AMIDES

 Amines are alkyl or aryl derivatives of ammonia (NH3) in which one or more of the hydrogen
atoms of the NH3 are replaced by alkyl group.
 According to the number of alkyl groups present, they are classified as primary amines (one
alkyl group directly linked with nitrogen), secondary amines (two alkyl groups directly linked
with nitrogen) and tertiary amines (three alkyl groups directly linked with nitrogen).
 As the amines are basic in nature due to the presence of lone pair of electrons on nitrogen, they
form salts with acids.
 The salts are considered related to ammonium (NH4+) in which all the four hydrogen atoms are
replaced by alkyl groups and are called as quaternary ammonium salts.
AMINES

 Individual amines derive their names from the alkyl groups present in it.
 If the alkyl groups present are same then it is called simple amines, if the alkyl groups
present are different then it is called mixed amines.
The rules for naming amines as per IUPAC nomenclature are described below.
 Name the alkyl groups attached to nitrogen atom followed by the suffix- amine.
 If two or more identical alkyl groups are attached to the nitrogen the prefix di or tri etc is
added to the amine name.
AMINES

 If two or more different alkyl groups are present, then they are named alphabetically.
 If the amine is complex, then the amino group is considered as substituent and lowest
possible number is assigned to it in the carbon chain.
 The amine salts are considered as substituted ammonium salts. The alkyl groups are
named first and word ammonium is added as a suffix. The name of anion present is
written as second word.
AMINES

 Alkyl halides are purely synthetic compounds and are rarely present in the nature.
 Chemically they are highly reactive species and serves as the starting material for very
large number of aliphatic compounds.
 These are analogues to inorganic metallic halides such as NaCl, NaBr, etc., but differ
from them by its covalent bond.
 These are prepared by the substitution reaction between alkanes and halogens to give
different derivatives in which one or more hydrogen atoms are replaced with one or ore
halogen atoms.
ALKYL HALIDES

COMMON NAME SYSTEM
 In this method alkyl group attached to halogen is mentioned first followed by the halide.
 The name of alkyl halide is mentioned as two words.
ALKYL HALIDES

IUPAC NAME SYSTEM
 Longest continuous chain containing halogen is selected and the compound is onsidered
as the derivative of that alkane.
 The carbon having the halogen atom should be given the least number and this number is
used to indicate the position of halogen in alkyl halide.
 If any other substituents are present, indicate their position while writing the name of
alkyl halide.
ALKYL HALIDES

ALKYL HALIDES

 Most of the organic compounds are cyclic in nature.
 Antibiotics being used to treat infectious diseases have cyclic ring as a part of core
structure, the carbohydrates that we eat to get energy are cyclic and the bases of nucleic
acid DNA and RNA are cyclic in nature.
 Cycloalkanes or cycloparaffins or polymethylenes are saturated, closed chain
hydrocarbons in which the carbon atoms connected by single covalent bonds lead to the
formation of rings, hence they are called as carbocyclic or homocyclic compounds.
 These are otherwise known as alicyclic compounds, the suffix cyclic indicates the
presence of a ring and the prefix ali indicates their similarity to aliphatic compounds.
 The general formula for this series is CnH2n.
CYCLOALKANES

 Line angle formula is used to draw the structures of cycloalkanes.
 The general formula has fewer hydrogen atoms less than that of the formula for acyclic
alkanes, because there is no end in the closed chain and no hydrogen atoms required to
cap off the ends of the chain.
 The first member of this series is cyclopropane.
 The four and five membered cycloalkanes are present in terpenes, the most important
classes of alicyclic compounds.
 The hydrocarbons of petroleum have five and six membered cycloalkanes known as
naphthenic acids as a major constituent.
CYCLOALKANES

 The name of unsubstituted cycloalkanes are derived by adding the prefix – cyclo to the
corresponding alkane possessing same number of carbon atoms, For example
 The substituents on the ring are numbered by providing least number to the substituents
and their positions are indicated in name. For example,
CYCLOALKANES

 Phenols are the organic compounds containing a benzene ring bonded to a hydroxyl
group.
 They are also known as carbolic acids.
 Thus, a phenol molecule consists of two parts one aryl group part and the other hydroxyl
group part.
 On the basis of the number of hydroxyl groups attached to the aryl group, it can be
classified into mono-, di-, tri- or polyhydric phenols.
 It is both a common name and an IUPAC name for the compounds containing a benzene
ring attached to a hydroxyl group.
 Structurally phenols are the simplest hydroxy derivative of the benzene ring.
PHENOLS

 Locate the position of a hydroxyl group attached to the benzene ring.
 Benzene rings attached to more than one hydroxyl group are labelled with the Greek
numerical prefixes such as di, tri, and tetra to denote the number of similar hydroxyl
groups attached to the benzene ring.
 If two hydroxyl groups are attached to the adjacent carbon atoms of the benzene ring, it
is named benzene1,2-diol.
 In the case of substituted phenols, we start locating the positions of the other functional
groups with respect to the position where the hydroxyl group is attached. For example, if
a methyl group is attached to the fourth carbon atom with respect to the hydroxy group,
the compound is named, 4-Methyl phenol.
PHENOLS
CH3
OH
o-Cresol
2-Methyl phenol

 Depending on the position of the substituted functional group with respect to the
hydroxyl group, words like ortho (when the functional group is attached to the adjacent
carbon atom), para (when the functional group is attached to the third carbon atom from
the hydroxyl group), meta (when the functional group is attached to the second carbon
atom from the hydroxyl group) are also used for the nomenclature of phenols.
PHENOLS
OH
OH
OH
OH
Catechol/
Benzene-1,2-diol Resorcinol/
Benzene-1,3-diol
OH
OH
Quinol/
Benzene-1,4-diol/
Hydroquinone
OH
o
m
p
o
m
1
2
3
4
5
6
OH

 Esters occur widely in nature.
 Unlike carboxylic acids, esters generally have pleasant odors and are often responsible
for the characteristic fragrances of fruits and flowers.
 Once a flower or fruit has been chemically analyzed, flavor chemists can attempt to
duplicate the natural odor or taste.
 Both natural and synthetic esters are used in perfumes and as flavoring agents.
 Although esters are covalent compounds and salts are ionic, esters are named in a
manner similar to that used for naming salts.
 The group name of the alkyl or aryl portion is given first and is followed by the name of
the acid portion.
 In both common and IUPAC nomenclature, the -ic ending of the parent acid is replaced
by the suffix -ate.
 The only difference is the name used for the acid portion: the common nomenclature
follows the common names used for acids, while the IUPAC nomenclature applies the
official prefixes to indicate numbers of carbon atoms on the main carbon chain.
ESTERS

ESTERS

NOMENCLATURE of organic compound pharm D poc

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NOMENCLATURE of organic compound pharm D poc