Nomenclature of Organic Compounds

Contents

• IUPAC Nomenclature of alkanes

• IUPAC nomenclature of cycloalkanes

• IUPAC nomenclature of

• Alkenes

• Dienes

• Alkynes

• Alkyl halides

• Alcohols

• Carboxylic acids

• Esters

• Acid halides

• Amides

• Identification of structures of the above classes

Learning Objectives

At the end of this lecture, student will be able to

• Identify the structure of a given compound belonging to the classes – alkanes and cycloalkanes

• Name above class of compounds according to IUPAC

• Identify the structure of a given compound belonging to the classes

• Alkenes

• Dienes

• Alkynes

• Alkyl halides

• Alcohols

• Name above class of compounds by IUPAC

• Identify the structure of a given compound belonging to the classes – carboxylic acids, esters, acid halides, and amides

• Give nomenclature of those compounds

Introduction to Nomenclature

• Common (trivial) names

• IUPAC (International Union of Pure and Applied Chemistry) names

• 4 parts of IUPAC name

• Prefix

• Locant

• Parent name

• Suffix

Alkanes

• Saturated hydrocarbons

• Homologous series & homologs

• General molecular formula CnH2n+2

Unbranched or Normal Alkanes

Structural Formula of Alkanes

Branched Alkanes

• Iso structural unit

• Neo structural unit

Alkyl Group Nomenclature

Unbranched alkyl groups

• Letter R indicates any alkyl group

• Branched alkyl groups

• 1°, 2°, 3° hydrogens

Nomenclature of Alkanes

• Locate longest continuous chain

• Substituent – lowest possible number

• Designate the substituent

• 2 or more substituent – arranged alphabetically

• Similar substituents – prefix di, tri, tetra…

• Hyphen and comma

• 2 chains of same length – choose with more substituent

• Branching at equal distance

Nomenclature of Cycloalkanes

• CnH2n

• Saturated hydrocarbons with a ring of carbon atoms in the molecule

• Prefix – cyclo

• Examples

• One substituents

• Two substituents

• More than 2 substituents

Nomenclature of Alkenes

• Unsaturated hydrocarbons, olefins

• General molecular formula CnH2n

• Replace suffix -ane by -ene

• Examples

• Rule 1

• Rule 2

• Rule 3

• Rule 4

• Rule 5

Nomenclature of Dienes

• Dienes and its types

• Rules

• General formula CnH2n-2

• Terminal & internal alkyne

• Replace -ane by -yne

• Rule 1

• Rule 2

Nomenclature of Alkyl Halides

• Alkyl halides or halo alkanes

• Rule 1

• Rule 2

Nomenclature of Alcohols

• Classification

• Common names

• IUPAC names

• Locate and number

• One substituent

• More than one substituent – alphabetical order

• Branching at equal distance

• Glycols or diols

Nomenclature of Carboxylic Acids

• Carboxylic acid

• Acyl group

• Carboxyl group – carbonyl group + hydroxyl group

• Systematic and common names

• Alkanoic acid

• Examples

 

Nomenclature of Esters

• Functional derivative of carboxylic acid

• Examples

Nomenclature of Acid Halides

• Functional derivative of carboxylic acid

• Alkyl halide

• Examples

Nomenclature of Amides

• Functional derivative of carboxylic acid – amide

• Examples

• Substituent on nitrogen

Summary

• Non-systematic names of organic compounds - trivial names or common names

• Systematic nomenclature of organic compounds - IUPAC names

• Alkanes – hydrocarbons that contain only single bonds

• Branched chain alkyl groups – indicated using the prefix iso, neo

• Cycloalkanes – saturated hydrocarbons with a ring of carbon atoms in the molecule

• IUPAC names of cycloalkanes – prefix ‘cyclo’ to the names of alkanes

• Alkenes – hydrocarbons that contain double bond

• Functional group of alkenes – double bond

• Functional group suffix of alkenes – ene

• Dienes – hydrocarbons that contain 2 double bonds, suffix - diene

• Alkynes – hydrocarbons that contain triple bond

• Functional group of alkynes – triple bond

• Functional group of alkynes – yne

• Alkyl halides – named as substituted alkanes

• Functional group of alkyl halide - X

• IUPAC name of alkyl halide – halo alkane

• Alcohols – named using functional group suffix

• Functional group of alcohol - OH

• IUPAC name of alcohol – alkanol

• Functional group of carboxylic acid – COOH

• IUPAC name of carboxylic acid – alkanoic acid

• Functional derivatives of carboxylic acid – esters, acid halides, amides

• IUPAC name of acid chloride - given by using the acid name and replacing “ic acid” with “yl chloride”

• IUPAC name of ester – name of the group R’ attached to the carbonyl group stated first followed by the name of the acid with ‘ic’ acid replaced by ‘ate’

• IUPAC name of amides – given by using the acid name, replacing “oic acid” or “ic acid” with “amide”