1. Introduction to Organic Chemistry
Chapter-4
Introduction to Organic Chemistry

2. What is Organic Chemistry?
It is defined as the study of hydrocarbons
(compounds of hydrogen and carbon) and
their derivatives
1.5 million Inorganic Compounds
7 million Organic Compounds

3. Organic Chemistry Carbon Compounds Organic Compounds
Inorganic Compounds
CO2 CO
XCN
XCO3
Hydrocarbons &
Derivatives
X=Metal

4. Animal and plant matter, Foods,
Organic Chemistry
We are enjoying the gifts of organic compounds directly or indirectly in our daily life such as
Animal and plant matter, Foods,
Fertilizers, Pharmaceuticals, Plastics,
Cosmetics, Clothing, Detergents etc..

5. Organic Chemistry Fertilizers Detergents Vegetables Organic compounds
Clothing
Foods
Cosmetics
Plastics
Medicine

6. General characteristics of organic compounds
Covalent compounds.
Contain 2 or more elements: C, H, O, N, S, P.
Vast numbers of different compounds.
Why?
Ability to form long chains and rings
Catenation 6

7. Covalent bond
Single covalent bond F
Lone pairs
Lone pairs

8. Covalent bond
lone pairs F
single covalent bond

9. Catenation

10. Hydrocarbon Hydrocarbons are the simplest organic molecules.
They contain only carbon and hydrogen.

11. Hydrocarbons

12. Classification of Hydrocarbons

13. Hydrocarbons Alkanes Alkenes Alkynes Arenes Simplest Methane,
ethane, propane 13

14. Alkanes are the simplest type of
Hydrocarbons

15. Names and Formulas for Some Common Hydrocarbons

16. The first 10 straight chain alkane

17. Methane Sp3 hybridized carbon 4 equivalent C-H bonds (s-bonds)
All purely single bonds are called s-bonds

19. The Molecular Structure of Methane

21. Structure of Ethane

22. The Structures of Propane and Butane

23. Normal Butane and Iso Butane

27. -H Alkane Alkyl radical -H CH4 -CH3
When a hydrogen atom is removed from an alkane the remaining group of atoms is called alkyl group or alkyl radical. -H
Alkane
Alkyl radical -H
CH4
-CH3

28. Alkyl group -H -H -H Methane CH4 CH3 Methyl Ethane C2H6 C2H5 Ethyl
Propane
C3H8
C3H7
Propyl

30. Functional group
An atom or a group of atoms which impart characteristics properties to a compound is called Functional group.

31. Functional group

32. Homologous series
A series of compounds of similar properties whose molecular formula differ by CH2 between adjacent members of the series

33. Homologous series The members show regular changes in properties n
Molecular formula
Name 1 4
CH4
Methane 2 6
C2 H6
Ethane 3 8
C3 H8
Propane 10
C4 H10
Butane 5 12
C5 H12
Pentane 14
C6 H14
Hexane 7 16
C7 H16
Heptane 18
C8 H18
Octane 9 20
C9 H20
Nonane 22
C10 H22
Decane
As the # C-atoms ↑:
reactivity ↓
mp ↑
bp ↑
d ↑
solubility ↓
The first 10 members of the alkanes (CnH2n+2)

34. Homologous series Formula Alkanes Cn H2n+2 Alkenes Cn H2n Alkynes
Alcohols
Cn H2n+1 OH
Alkyl halides
Cn H2n+1 X (X= F, Cl, Br, I)
Homologous series
Formula

35. Homologous series Formula Aldehydes Cn H2n+1CH O Ketones C nH2n CO
Carboxylic acids
Cn H2n+1 CO2 H
Amides
Cn H2n+1 CONH2
Amines
Cn H2n+1 NH2
Homologous series
Formula

36. Saturated hydrocarbons Unsaturated hydrocarbons
Single bond
Double bond
Triple bond
Alkanes
Alkenes & Alkynes
Substitution rxn
Addition rxn

37. Which of the following compounds is saturated
and which is
unsaturated 37

38. Chemical formula
Structural formula
Molecular formula 38

39. Molecular formula Gives the numbers of each atom in a molecule
Ethane C2H6

40. Shows, in 2-dimensions,exactly how the atoms are bonded to each other
Structural formula
Shows, in 2-dimensions,exactly how the atoms are bonded to each other

41. Examples Structural formula Molecular formula Methane Ethane Propane
CH4
C2H6
C3H8

42. Examples
Molecular formula
Structural formula
C4H10
C2H6O

43. Chemical formula
Write down the molecular and structural formulae of the first six alkanes.

44. Isomerism

45. Isomerism
Different molecules have the same molecular formula but different structural formula
Isomers
Different physical
&
chemical properties 45

46. Examples
Molecular formula
Structural formula
C4H10 46

47. Examples
Molecular formula
C2H6O
Structural formula

48. Types of Isomerism

49. Chain Isomerism or Skeletal Isomerism
Compounds having same molecular formula but different carbon chain or carbon skeleton are called chain isomers and this phenomena is known as chain isomerism
“This type of isomers differ only in the structure of their carbon chains or skeletons” 49

50. For example
The molecular formula C5H12 , represents three isomeric alkanes differing only in structure of their carbon chains:

51. n-pentane C H

52. 2-methylbutane H
CH3 C C C C

53. 2,2-dimethylpropane C H
CH3

54. Position Isomerism
Compounds having the same molecular formula but differ in the relative position of their functional group or the position of their double or triple bonds are called position Isomer . 54

55. Position Isomerism 1-Chlorobutane 2-Chlorobutane
Molecular formula C4H9Cl represents two isomers in which the relative position of Cl is different, but they have the same carbon skeleton.
CH3 - CH2 - CH2 - CH2-Cl
1-Chlorobutane Cl –
2-Chlorobutane
CH3 - CH2 - CH – CH3

56. Position Isomerism Butan-1-ol Butan-2-ol CH3 - CH2 - CH2 - CH2-OH

57. position Isomer

58. This isomerism is common in two types of
Functional Group Isomerism
Compounds having the same molecular formula but different functional groups are called functional groups isomers
This isomerism is common in two types of
compounds:
Ethers
Alcohols

59. functional groups isomers

60. One of these is an ether and the other is an alcohol.
Example
The molecular formula C2H6O has at least two isomers which have different functional groups.
One of these is an ether and the other is an alcohol.
Ethers
Alcohols

61. Aldehydes & Ketones

62. Molecular formula C3H6O represents one aldehyde and one ketone as
Example
Molecular formula C3H6O represents one aldehyde and one ketone as
CHO
CH3CH2
ketone
Aldehyde

63. Metamerism

64. This isomerism is exhibited by ethers and amines.
In this type of isomerism different alkyl groups are attached to the same polyvalent atom, such as O or N.
This isomerism is exhibited by ethers and amines.

65. Molecular formula C4H10O represents three different ethers.
Example
Molecular formula C4H10O represents three different ethers.
CH3-CH2-O-CH2-CH3
CH3-O-CH2-CH2-CH3
Diethyl ether
Methyl Propyl ether

66. Classification of Carbon Atoms
Primary Carbon
Secondary Carbon
Quaternary Carbon
Tertiary Carbon

67. to one other carbon atom to two other carbon atoms
Secondary Carbon
Primary Carbon
A carbon atom attached
A carbon atom attached
to one other carbon atom
to two other carbon atoms

68. Quaternary Carbon Tertiary Carbon A carbon atom attached to four other
carbon atoms
A carbon atom
attached to three
other carbon atoms
Quaternary Carbon
Tertiary Carbon

70. Classification of carbon atoms

71. Organic Nomenclature

72. Common or Trivial System

73. This method of nomenclature was used before 1892.
In this system of nomenclature, the compounds were named on the basis of their history, such as source of origin etc.

74. IUPAC
SYSTEM

75. A method known as the Geneva system was suggested in 1892 by the International Chemical Congress at Geneva for naming organic compounds.

76. Later the International Union of Chemistry at Liege (Belgium) developed it into IUPAC system of nomenclature in 1930.
In 1958, the IUPAC system was modified by the International Union of Pure and Applied Chemistry (IUPAC) into the present day IUPAC system of nomenclature.

77. Rules for naming alkanes

78. Rule 1:
Selection of longest continuous chain of carbon atoms as the parent name of the hydrocarbon.
butane
The longest continuous chain has four carbon atoms, thus the compound is named as butane.

79. Rule 2:
Number the carbon atoms in the longest continuous chain in such a way as to give lowest possible number to carbons atoms carrying substituent's.
CH3 CH
CH2 1 2 3 4 5
2-methylpentane

80. CH3 CH
CH2 5 4 3 2 1
4-methylpentane

81. Incorrect numbering
Correct numbering

82. The attached group is located on carbon 2 of the chain, and it is a
Rule 3:
Name the substituent.
Indicate its position by the number of the carbon atom to which it is attached.
The attached group is located on carbon 2 of the chain, and it is a
methyl group

83. The whole name is written as one word.
Rule 4:
Prefix the position number and name of the substituent onto the parent name.
The whole name is written as one word.
Notice that the number and name of the substituent are separated by a hyphen.

84. 2-Methylbutane 2- Butane Methyl Attached alkyl group Longest chain
Position of alkyl group
2-Methylbutane

85. Rule 5:
If identical substituent's are present more than once in the molecule, then use prefixes di- tri-tetra-,penta-, etc.

86. Position of each substituent is indicated by a separate number.
Rule 6:
Position of each substituent is indicated by a separate number.

87. Rule 7:
When two or more different substituent's are present, their names are arranges in alphabetic order and added to the name of the parent alkane, again as one word.

88. CH3
CH2 CH 1 2 3 4 5 6 7
4-methylheptane

89. Nomenclature guideline

90. Step-by-step procedure to write the IUPAC names from structural formula.

91. Step 1 Identify the longest chain.
In this example, the longest chain contains seven carbons. the seven-carbon chain is heptane.

92. Step 2 Number the chain. The chain is numbered from left to right.
This gives the lowest numbers to the attached alkyl groups.

93. Step 3 Identify the alkyl groups.
There are two methyl groups at C-2 and C-3.
There is one ethyl group at C-4

94. Step 4 Write the IUPAC name: In this case the IUPAC name is
4-Ethyl-2,3-dimethylheptane

95. Always remember

96. Numbers are separated from each other by commas;
Numbers are separated from names by
hyphens;
Prefixes di-, tri-, are not taken into account in alphabetizing substituent names.

97. Structural formulas from the IUPAC names

98. Consider the following IUPAC name:
Step-by-step procedure to draw structural formulas from the IUPAC names.
Consider the following IUPAC name:
3,3-Diethyl-5-methyldecane

99. Step1
Draw a decane skeleton and number it.

100. Step 2
Attach two ethyl groups at C-3
C2H5
C2H5

101. Step 3:
Attach a methyl group at C.5
CH3

102. Supply hydrogen atoms so that each carbon atom has four bonds.
Step 4
Supply hydrogen atoms so that each carbon atom has four bonds.

103. Draw structural formulas for the following compounds
2,3-dimethylhexane
CH3 CH
CH2 1 2 3 4 5 6

104. 3,3-dimethylhexane 2-bromo-3-nitrobutane CH3 CH2 C CH3 CH Br NO2 1 2 34 5 6
2-bromo-3-nitrobutane
CH3 CH Br 1 2 3 4
NO2

105. 1-bromo-3-nitrobutane
CH2 CH
CH3 Br 1 2 3 4
NO2

106. What is the IUPAC name of the following compound?
CH3 CH
CH2
C2H5 1 2 4 5 6 8 3 7
4-ethyl-2-methyloctane

107. What is the structure of 2,4-dimethylhexane?1 2 3 4 5 6
CH3 CH
CH2

108. What is the IUPAC name of the following compound?
CH3
CH2 CH 1 2 3 4 5 6 7
4-methylheptane

109. Cyclo Alkanes

110. They have the general formula CnH2n
Alkanes whose carbon atoms are joined in rings are called cycloalkanes.
They have the general formula CnH2n
where n = 3,4,…
They are named by attaching the prefix cyclo- to the name of the alkane having the same number of carbons as in the ring.

111. Cycloalkanes are often represented by simple geometrical figures.
Cyclopropane
is represented by a
Cyclobutane
is represented by a
Cyclopentane
is represented by a
Cyclohexane
is represented by a

112. It is understood that each corner represents CH2 group.
Cyclo Alkanes
It is understood that each corner represents CH2 group.

113. Cyclo Alkanes

114. Structure of Cyclopropane

115. Substituted Cycloalkanes are named as
The substituent's on the ring are named
and their position is indicated by
numbers.
The ring is numbered so that the substituent's are given the lowest possible
Alkylcycloalkanes

117. The ring is designed as a substituent if the
alkane chain contains a greater number of
carbon atoms than the ring.

118. Alkenes

119. where n = 2,3,… Alkenes have the general formula CnH2n
Contain at least one carbon-carbon double bond also called olefins
where n = 2,3,…

120. A Carbon-Carbon Double Bond Consists
of a sigma and a pi Bond

121. CH2 CH
CH3
CH3 CH
1-butene
2-butene

122. cis-dichloroethylene trans-dichloroethyleneCl H C Cl H
cis-dichloroethylene
trans-dichloroethylene

123. Rules for Naming Alkene's
IUPAC
Rules for Naming Alkene's

124. Rule 1
Select the longest continuous chain of carbon atoms containing the double bond, as the parent chain.

125. Rule 2 Alkane Alkene -ane +ene
Name the longest chain. The name is obtained by replacing ane of alkane with ene.
-ane
Alkane Alkene
+ene
Pentene

126. Number the chain from the end closer to the double bond.
Rule 3
Number the chain from the end closer to the double bond.

127. Rule 4
Indicate the position of the double bond by the number of the first (lowest numbered) carbon atom involved in the double bond.
Carbon-2

128. Rule 5
Alkyl groups and other substituent's are numbered , named and placed as prefixes in alphabetical order.

129. Alkenes containing two double bonds are named as
Rule 6
If more than one double are found then use the prefixes di,tri,tetra,for 2,3 and 4.
Alkenes containing two double bonds are named as
Alkadienes

131. Cycloalkenes

132. In naming Cycloalkenes, number the ring to give the double bonded carbons the numbers 1 and 2 , choose the direction of numbering so that the substituent's get the lowest numbers.

133. The position of the double bond is not indicated because it is known to be between
C-1 and C-2.

134. Alkynes

135. Alkynes are hydrocarbons have the general formula CnH2n-2 where
Alkynes contain at least one carbon-carbon triple bond

136. The simplest alkynes is Ethyne commonly called
Acetylene

137. The Bonding in Acetylene

139. Production of acetyleneCH C
CH2
CH3
CH3 C
1-butyne
2-butyne
CaC2 (s) + 2H2O (l) C2H2 (g) + Ca(OH)2 (aq)
Production of acetylene

140. Rule 1
Select the longest continuous carbon chain containing at least one triple bond, as the parent chain.

141. Rule 2 alkane Alkynes Hexyne -ane +yne
Name the longest chain. The name is obtained by replacing ane of alkane with yne.
-ane
alkane
Alkynes
+yne
Hexyne

142. Number the chain from the end closer to the triple bond.
Rule 3
Number the chain from the end closer to the triple bond. 1 2 3 4 5 6

143. Rule 4
Indicate the position of the triple bond by the number of the first (lowest numbered) carbon atom involved in the triple bond. 1 2 3 4 5 6
Carbon -2

144. Rule 5
Alkyl groups and other substituent's are numbered, named and placed as prefixes in alphabetical order. 1 2 3 4 5 6
5-methyl-2-hexyne

145. Alkenes containing two triple bonds are named as
Rule 6
If more than one triple are found then use the prefixes di,tri,tetra,for 2,3 and 4.
Alkenes containing two triple bonds are named as
Alkadiyne

147. Alkyl halides are compounds which contain carbon-halogen bonds.
They are classified as primary, secondary,and tertiary alkyl halides.
Abbreviations for these terms are 1°, 2°, and 3°, respectively.

148. The common names of alkyl halides are obtained by naming the alkyl group attached to the halogen and adding the name of the halide as a separate word

149. Naming Alkyl Halides
Alkyl halides are named in the same way as alkanes by treating the halogen as substituent on a parent alkane chain.

150. Select the longest continuous carbon chain as the parent chain.
Rule 1
Select the longest continuous carbon chain as the parent chain.

151. Number the chain from the end closer to the substituent's.
Rule 2
Number the chain from the end closer to the substituent's. 1 2 3 4 5 6

152. Rule 3
If more than one of the same kind of halogen is present, number each and use one of the prefixes di-, tri-, tetra-, and so on.

153. Rule 4
If different halogens are present, number each according to its position on the chain and list them in alphabetical order when writing the name.

154. CH3I can be called methyl iodide.
In addition to their systematic names, many simple alkyl halides are also named by identifying first the alkyl group and then the halogen.
For example,
CH3I can be called methyl iodide.
Such names are well entrenched in the chemical literature and in daily usage.

157. Alcohols
Alcohols are compounds in which a hydroxyl group (-OH) is bonded to a saturated carbon.

158. Classification of alcohals
They are classified as primary, secondary, or tertiary alcohal.
Abbreviations for theses terms are 1°, 2°, and 3°, respectively.

159. Primary Acohal

160. SecondaryAcohal

161. Tertiary cohal

162. IUPAC Rules for naming Alcohols.

163. Rule 1
Select the longest continuous carbon chain to which the hydroxyl group is attached as the parent chain.

164. The name is obtained by replacing the final -e with-ol.
Rule 2
Name the longest chain
The name is obtained by replacing the final -e with-ol. -e
alkane
Alkanol
+ol

165. Rule 3
Number the chain to give the lowest number to carbon attached to the hydroxyl group.

166. Rule 4
Indicate the position of the hydroxyl group by the number of the carbon attached to the hydroxyl group.

167. Rule 5
Other substituent's are numbered, named, and placed as prefixes in alphabetic order For example:

168. Rule 6
Alcohols containing two or three –OH groups are named as Alkanediols and Alkanetriols respectively. Notice that –e of the corresponding alkane name is retained.

169. IUPAC Rules for Naming Aldehydes
Select the longest chain containing the aldehyde group.

170. Rule 2 Alkane -e + al = Alkanal Pentanal Name the longest chain.
The name is obtained by dropping the final .e
from the name of the corresponding alkane, and adding the ending -al
Alkane -e + al = Alkanal
Pentanal

171. Number the chain by assigning the number 1 to the aldehyde carbon.
Rule 3
Number the chain by assigning the number 1 to the aldehyde carbon. 1 5 4 3 2

172. Rule 4
Other substituent's are numbered, named, and placed as prefixes in alphabetic order.

173. Notice that .e of the corresponding alkane name is retained.
Rule 5
When there are two aldehyde groups in a molecule, it is named as “Alkanedial”.
Notice that .e of the corresponding alkane name is retained.

174. Ketones
Ketones are compounds in which carbonyl group (C=O) is bonded to two organic groups.

175. Select the longest chain containing the carbonyl carbon atom.
IUPAC Rules for naming Ketones
Rule 1
Select the longest chain containing the carbonyl carbon atom.

176. Alkane -e + one = Alkanone.
Rule 2
Name the longest chain.
The name is obtained by dropping the final-e
from the name of the corresponding alkane, and adding the ending .one.
Alkane -e + one = Alkanone.

177. Number the chain to give the lowest number to the carbonyl carbon.
Rule 3
Number the chain to give the lowest number to the carbonyl carbon. 1 5 4 3 2

178. Rule 4
Other substituent's are numbered, named, and placed as prefixes in alphabetic order. 1 5 4 3 2

179. Rule 5
When there are two carbonyl groups in a molecule, it is named as Alkanedione.

180. Rule 6