1. Case Western Reserve University
Organic Chemistry
4th Edition
Paula Yurkanis Bruice
Chapter 2
An Introduction to
Organic Compounds
Nomenclature,
Physical Properties,
and
Representation of
Structure
Irene Lee
Case Western Reserve University
Cleveland, OH
©2004, Prentice Hall

2. Alkanes are hydrogen carbons containing only single
bonds
General formula: CnH2n+2

3. Constitutional isomers have the same molecular
formula, but their atoms are linked differently

4. Nomenclature of Alkyl Substituents

6. A C7H16 compound can be any one of the following:
A compound can have more than one name, but a
name must specify only one compound
A C7H16 compound can be any one of the following:

7. Different Kinds of Carbons and Hydrogens

8. Nomenclature of Alkanes
1. Determine the number of carbons in the parent hydrocarbon
2. Number the chain so that the substituent gets the lowest
possible number

9. 3. Number the substituents to yield the lowest possible number
in the number of the compound
(substituents are listed in alphabetical order)
4. Assign the lowest possible numbers to all of the substituents

10. 5. When both directions lead to the same lowest number for one
of the substituents, the direction is chosen that gives the lowest
possible number to one of the remaining substituents
6. If the same number is obtained in both directions, the first
group receives the lowest number

11. 7. In the case of two hydrocarbon chains with the same number of
carbons, choose the one with the most substituents
8. Certain common nomenclatures are used in the IUPAC system

12. Nomenclature of Cycloalkanes
1. No number is needed for a single substituent on a ring
2. Name the two substituents in alphabetical order

13. 3. If there are more than two substituents,

14. Nomenclature of Alkyl Halides
In the IUPAC system, alkyl halides are named as substituted
alkanes

15. Different Kinds of Alkyl Halides

16. Nomenclature of Ethers
As substituents:

17. Nomenclature of Alcohols
In an alcohol, the OH is a functional group
A functional group is the center of reactivity in a
molecule
1. Determine the parent hydrocarbon containing the functional
group

18. 2. The functional group suffix should get the lowest number
3. When there is both a functional group suffix and a substituent,
the functional group suffix gets the lowest number

19. 4. If there is more than one substituent, the substituents are cited
in alphabetical order

20. Nomenclature of Amines
The substituents are listed in alphabetical order and a number or
an “N” is assigned to each one

21. Naming Quaternary Ammonium Salts

22. Structures of Alkyl Halides

23. Structures of Alcohol and Ether

24. Structures of Amines

25. Dipole–dipole interaction
Attractive Forces
van der Waals force
Dipole–dipole interaction
Hydrogen bonds
The greater the attractive forces between molecules,
the higher is the boiling point of the compound

26. van der Waals Forces
The boiling point of a compound increases with the
increase in van der Waals force

27. Dipole–Dipole Interaction
Dipole–dipole interactions are stronger than van der
Waals force but weaker than ionic or covalent bonds

28. A hydrogen bond is a special kind of dipole–dipole
interaction

30. Like Dissolves Like Polar compound dissolves in polar solvent
Nonpolar compound dissolves in nonpolar solvent

31. Conformations of Alkanes: Rotation about Carbon–Carbon Bonds

32. Different Conformations of Ethane
A staggered conformer is more stable than an eclipsed
conformer
Torsional strain: repulsion between pairs of bonding
electrons

33. Conformations of n-Butane
Steric strain: repulsion between the electron clouds of
atoms or groups

34. Cycloalkanes: Ring Strain
Angle strain results when bond angles deviate from the
ideal 109.5° bond angle

35. The chair conformation of cyclohexane is free of strain

36. Ring Flipping in Cyclohexane

37. Drawing Cyclohexane

38. The Conformations of Cyclohexane
and Their Energies

39. Conformations of Monosubstituted Cyclohexanes

40. Steric Strain of 1,3-Diaxial Interaction in Methylcyclohexane

41. The larger the substituent on a cyclohexane ring, the
more the equatorial substituted conformer will be
favored
Keq = [equatorial conformer]/[axial conformer]

42. The Chair Conformers of cis-1,4-Dimethylcyclohexane

43. The Chair Conformers of trans-1,4-Dimethylcyclohexane

44. 1-tert-Butyl-3-Methylcyclohexane

45. Conformations of Fused Rings
Trans-fused cyclohexane ring is more stable than
cis-fused cyclohexane ring