Naming Organic Compounds, Alkanes, and CycloAlkanes

Naming Organic Compounds, Alkanes, and CycloAlkanes

1. Section 9.2 (pg. 366-374)
Naming Organic
Compounds
Today’s Objectives:
1)Name and draw structural, condensed structural, and line diagrams and
formulas for saturated and unsaturated aliphatic (including cyclic)
•Containing up to 10 carbon atoms in the parent chain/cyclic structure
•Containing only one type of a functional group or multiple bond
•Using the IUPAC nomenclature guidelines

2)Identify types of compounds from the functional groups, given the structural
formula

3)Define structural isomerism and relate to variations in properties

2. Four Types of Formulas
1.Molecular Formulas C
5H
10(g)
Not very useful for organic
compounds because so many
isomers can exist

2.Structural Formulas

1.Condensed Structural Formulas

2.Line Diagrams
– end of line segment represents carbon
– it is assumed to satisfy each carbon’s octet

3. Naming Organic Compounds
Aliphatic Hydrocarbons – contains only hydrogen and carbon atoms
Straight line chains of carbon atoms
Alicyclic hydrocarbons have carbon atoms forming a closed ring. Still
considered aliphatic


Alkanes Alkenes Alkynes
Only single C-C
bonds

Double C-C Bond
present
Triple C-C bond
present
General formula
C
nH
2n+2
General formula:
C
nH
2n
General formula:
C
nH
2n-2
Saturated
Unsaturated Unsaturated

4. In organic chemistry, names
have a root and a suffix.
The root describes the number
of carbons present in the chain
or ring.
The suffix describes the type of
compound it is.
Naming Organic Compounds

5. Naming Organic Compounds

6. Naming ALKANES
1.Find the parent chain (the longest continuous chain
of carbon atoms). Use the appropriate root and
the suffix-ane.

7. Naming ALKANES
1.Find the parent chain. Use the appropriate root and suffix.
2.Number the carbon atoms, starting from the end closest to the
branch(es) so that the numbers are the lowest possible
3.Identify any branches and their location number on the parent chain
(us the suffix –yl for branches)
4.Write the complete IUPAC name, following the format: (number of
location, if necessary) – (branch name) (parent chain)




2-methylheptane

8. If more than one of the same branch exist, use a multiplier to
show this (di, tri). Remember to include all numbers







Draw 2,4,6-trimethylheptane

Naming ALKANES

9. If different branches exist, name them in alphabetical order









ethyl before methyl (e before m in the alphabet)
Naming ALKANES

10. If there is more than one
branch of the same type, a
locating number is given to
each branch and a prefix
indicating the number of that
type of branch is attached to
the name.
This numbering prefix does
not affect the alphabetical
order of the branches
Draw the structural formula
for 3,4-dimethylhexane
Naming ALKANES

11. Summary of Naming Alkanes
1.Find the parent chain. Use the appropriate root and suffix.
2.Number the parent chain carbon atoms, starting from the end
closest to the branch(es) so that the numbers are the lowest
possible
3.Identify any branches and their location number on the
parent chain (us the suffix –yl for branches)
4.If more than one of the same branch exist, use a multiplier
(di, tri) to show this. Remember to include all numbers
5.If different branches exist, name them in alphabetical order
6.Separate numbers from numbers using commas, and
numbers from words using dashes (no extra spaces)

12. Don’t forget
Questions will specifically
ask about structural,
condensed structural or
line structural formulas.

You must be comfortable
drawing any of the three

13. Practice
Write the IUPAC name for the following





2,5-dimethyl-4-propyloctane

14. Correct the following names:
4-ethyl-2-methylpentane






ACTUALLY 2,4-dimethylhexane
ALWAYS LOOK FOR LONGEST CHAIN!!

15. Correct the following name:
4,5-dimethylhexane




Actually 2,3-dimethylhexane
**Want branch numbers to be as low as possible

16. CYCLOALKANES
Based on evidence, chemists believe that organic carbon compounds
sometimes take the form of cyclic hydrocarbons:
Cycloalkanes: Alkanes that form a closed ring
General Formula C
nH
2n
Two less hydrogens are present than in straight chain alkanes because
the two ends of the molecule are joined
Are these considered saturated?? Yes, because they have only single
bonds and the max amount of hydrogen's bonded to the carbons
Cyclo-compounds will have a higher boiling point than their straight
chain partners (because there is an additional bond present)

17. Cycloalkanes are named by placing the prefix cyclo in front
of the alkane name, as in cyclopropane and cyclobutane
If branches are present, treat the cycloalkane as the parent
chain and identify the branches.
Since there is no end at which to start the numbering, use the
lowest numbers possible

Naming CYCLOALKANES

18. Name the following:
1. 2.




1,2-dimethylcyclopentane ethylcyclohexane
**Why don’t we need a number?

19. Today’s homework
Pg. 370 #7 (a-c) ,9, 10 (a-b) 11 (a-c)
Pg. 372 #5-6

What is coming up tomorrow?
Naming Alkenes, Alkynes, Cycloalkenes and
Cycloalkynes
Comparing properties of Isomers