1. Dr. Nesma Mamdouh Bayoumy
Organic Chemistry
For Dental Students
Dr. Nesma Mamdouh Bayoumy
Lecture (1)
Spring, 2015

2. An Introduction to Organic Compounds Chapter 1
Organic chemistry is that branch of chemistry that deals with the structure, properties, and reactions of compounds that contain carbon.
Organic compounds are the compound which contains mainly carbon and hydrogen.

3. Hydrocarbons Saturated Unsaturated Alkanes CnH2n+2 Alkenes Alkynes

4. IUPAC Nomenclature The Three Basic Parts Basic Part – Suffixes
The name for any organic molecule consists of three basic parts:
Prefixes-Parent-Suffix
Basic Part – Suffixes
Suffixes on the end of the name of an organic molecule tell you what major family the molecule belongs to
The suffix for an alkane is “-ane”
The suffix for an alkene is “-ene”
The suffix for an alkyne is “-yne”

5. Counting to Ten in Organic
Basic Part – the Parent
The “parent” part of the name tells you how many carbons are in the longest chain “main chain” of the molecule.
Counting to Ten in Organic
01 = meth
02 = eth
03 = prop
04 = but
05 = pent
06 = hex
07 = hept
08 = oct
09 = non
10 = dec

6. Parent and suffix… The parent is named based on the number of carbons
1 carbon = “meth”
So a one-carbon alkane is called methane CH4
2 carbons = “eth”
So a two carbon alkane is called ethane.
CH3CH3
3 carbons = “prop”
So a three carbon alkane is called propane.
CH3CH2CH3
4 carbons = “but”
So a four carbon alkane is called butane.
CH3CH2CH2CH3

7. Prefixes Prefixes – the Halides
So name the following alkane (shown as both condensed formula and a skeletal structure)
Prefixes
Prefixes are any substituent attached to the main chain (parent) of the molecule.
Prefixes – the Halides
Chlorine is called “chloro”
Fluorine is called “ Fluoro”
Bromine is called “bromo”
Iodine is called “iodo
Answer?
nine carbons + alkane family = NONANE

8. Putting together a name…
The rules for IUPAC nomenclature include:
Step 1: Find the main chain (Longest chain)
Step 2: Number the main chain
Step 3: Identify all prefixes and their position numbers
Step 4: Write the full name: Prefixes-Parent-Suffix.
Step 5: Add punctuation.
Put commas between numbers (2 5 5 becomes 2,5,5)
Put a hyphen between a number and a letter (2 5 5 trimethylheptane becomes 2,5,5-trimethylheptane)
Successive words are merged into one word (trimethyl heptane becomes trimethylheptane)

9. Follow the rules… Name the following…
4-Bromoheptane
3,4-Dibromoheptane
3-Bromo-1-chloro-4-methylhexane
1,1-Dibromo-3-methyloctane
3-ethylhexane

10. Alkyl Groups Alkyl groups are named similarly to alkanes.
If you remove a hydrogen atom from one of these you get an alkyl group.
A fragment of methane, CH4, would be CH3- called “methyl”
A fragment of ethane, CH3CH3, would be CH3CH2-, called “ethyl”.
Example:
3-ethylhexane

11. IUPAC Systematic Nomenclature - Alkanes
If compound has two or more chains of the same length, parent hydrocarbon is chain with greatest number of substituents.
Quiz
Draw Some Simple Alkanes:
2-methylpentane
3-ethylhexane

12. Example 1:  Write the structural formula for 2-methylpentane
Start from counting the number of carbon atoms in the longest chain - pent counts 5 carbons.
Are there any carbon-carbon double bonds?
No – an tells you there aren't any.
Now draw this carbon skeleton:
Put a methyl group on the number 2 carbon atom:
Write the structural formula: 2,3-dimethylbutane. 2,2-dimethylbutane. 3-ethyl-2-methylhexane. 4-bromo-3-methylhexene.

13. Propyl Groups
There are two possible three-carbon alkyl groups to form from propane, CH3CH2CH3.
The straight chain version: CH3CH2CH2- which is called “propyl” or “n-propyl” (where n stands for “normal” or straight-chained)
The other possibility is to form the fragment on the central carbon: CH3CHCH3, which is called “isopropyl”
Name the following molecule:

14. There are two options: Option 1 is highlighted in red:
The red one has two branches
Option 2 is highlighted in blue:
The blue one has three branches
Eight carbons in main chain. Octane.
Three alkyl groups attached:
2-methyl
5-propyl
6-methyl
Full name: 2,6-dimethyl-5-propyloctane.

15. Nomenclature of Substituents
The name of the alkyl group followed by the name of the class of compound constitutes the common name for alcohols amines, and alkyl halides:
Suffix
General Formula
Function Class Ol OH
Alcohols al
CHO
Aldehydes
one
C=O
Ketones
ether
-O-
Ethers
oate
-COO-
Esters
oic acid
-COOH
Carboxylic acids
amine
NH2
Amines

16. For each of the compounds A through G shown below, enter the appropriate IUPAC suffix in the designated answer box. In the second answer box enter a number indicating the number of carbon atoms in the longest chain.
Compound
IUPAC suffix
Chain length

17. Dr. Nesma Mamdouh Bayoumy
Organic Chemistry
For Dental Students
Dr. Nesma Mamdouh Bayoumy
Lecture (2)
Spring, 2015

18. Examples:

19. 4-chloro-5,5-dimethylhex
Name the following:
3-methylpentanoic acid
but-3-enoic acid
4-chloro-5,5-dimethylhex
-1-en-3-ol
4-bromo-5,6-dimethylheptan-2-amine
3-ethyl-2,2,4,5-tetramethylhexane

20. Name the following: Hexa-1,4-diene Pent-3-en-1-yne Hexa-1,3-dien-5-yne
3,4-Dipropyl-1,3-hexadien-5-yne
4-bromo-7-methyl-2-nonene
5-fluoro-7,7-dimethyl-2,4-octadiene

21. Nomenclature of Cycloalkanes
Cycloalkanes generally are shown as skeletal structures:

22. Nomenclature of Cycloalkanes
Ring is the parent hydrocarbon unless the alkyl substituent has more carbons; in that case the substituent becomes the parent hydrocarbon.
If only one substituent, no need to give it a number:

23. Examples: cyclobutylhexane propylcyclopentane
1,1,2-trimethylcyclobutane
2-chloro-1,3-dimethyl
cyclohexane
3-isopropylcyclo
pent-1-ene
3-ethylcyclohept-1-ene

24. The line formula for a cyclic compound is shown below.
Give the IUPAC name
Suffix
Number of ring carbons
The IUPAC name :
3-ethyl-5,5-dimethylcyclohept-2-en-1-one
The Suffix:
ONE
The number of carbons:
7 carbons

25. A line formula for a compound is shown below.
How many carbon atoms are in the root chain?
Give the IUPAC name for this compound?
Answer:
Number of carbons 5
The IUPAC name:
4-chloro-2-ethyl-3-methylpent-4-enoic acid

26. Give the IUPAC name for the following
4-isopropyl-1-ethyl-2-propylcyclohexane
3-ethyl-1,5,5-trimethylcyclohexene
1-cyclohexylheptan-3-ol
4-bromo-7-chloro-3-isopropylcyclo hept-1-ene

28. Benzene Derivatives 1-methyl-2-propylbenzene
1-bromo-4-ethyl-2-isopropylbenzene
1,3,5-trimethylbenzene