1. Organic Naming Rules Chem 332 For complete Rules go to:

2. Organic Compounds Carbon Hydrogen Oxygen Nitrogen
Consist of mainly four elements
Carbon
Hydrogen
Oxygen
Nitrogen

3. Why Do We Need a Separate Set of Rules?
Examine some typical organic compounds
CH4
C2H6
Name these using typical covalent rules
Carbon tetrahydride
Dicarbon hexahydride

4. So? How about these: C4H10 C5H12 See my point? Tetracarbon decahydride
Pentacarbon ??? hydride
Does anyone know the prefixes beyond ten?

5. C4H10 C4H10 Isomers Different Structure Same Formula
If that’s not enough, how about this one: C H
Different Structure
Same Formula C H
Formula?
Formula?
Definition: Isomer- chemicals that have the same formula but different structures
C4H10
C4H10

6. Overall Problems Memorizing too many prefixes for large numbers
Different chemicals having the same formulas
Keep in mind that thus far we’ve only dealt with TWO different elements!

7. So what to do?
Number of hydrogens is going to be the same, regardless of isomerism C H C H C H
C5H12
C5H12
C5H12

8. Solution
Since number of hydrogens don’t change with isomerism, why bother naming them?
Name the molecule simply based on number of CARBONS
We can always add prefixes or suffixes later for differentiation
The number of hydrogens will change later but for right now with only single bonds, they will always be the same.
What is the equation for C & H in an alkane? CnH2n+2

9. Name based on number of Carbons1 2 3 4 5 6 7 8 9 10
Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
Note the differences between this list and the covalent prefixes. Only the first four are diffferent.

10. Did that Really Help? CH4 C2H6 C8H18 C H Carbon tetrahydride becomes:
Methane
C2H6 C H
Dicarbon hexahydride becomes:
Ethane C H
C8H18
Octane
Octacarbon ???hydride becomes:

11. Alkanes Alkanes are hydrocarbons that contain only single bonds.
The general formula for alkanes is: CnH2n+2
n represents the number of carbon atoms in the molecule

12. Some Practice
What is the formula for an alkane that has 6 carbon atoms?
Use the general formula to figure this out.
Draw out the dot structure for this molecule.
Do all carbon atoms share 4 times?
Do all hydrogen atoms share 1 time?

13. Hmm, not too bad! If there are 6 carbon atoms,
then the H atoms must equal 14
Formula = C6H Hexane
Dot Structure
C – C – C – C – C – C

14. Branches
Straight-chain alkanes (Just C & H with single bonds) are now easy C H
C4H10 Butane
But how do we deal with branches? C H
C4H10 ????

15. Rules pt. 2 Identify the longest unbranched chain of carbons
Name it as normal
Identify the branch
Name it but give it a “–yl” suffix
Put the names of all branches first, then put name of longest chain

16. Methyl Propane Example methyl propane Branch is one long
Longest unbranched chain of carbons is three long
propane
Methyl Propane

17. Practice C H
Methyl butane H C
Ethyl pentane

18. One More Practice Methyl Butane It doesn’t matter which way you go!
(Provided you correctly pick the longest unbranched chain)
You can turn corners, go up, down, left, right, zig-zag, or do what ever you want provided you don’t double back on yourself. C

19. Methyl Hexane Be Careful Methyl Hexane C
This is your longest uninterrupted chain
Hexane
Remember that molecules don’t care about left or right, top or bottom.
Methyl Hexane

20. A Small Wrinkle Methyl Pentane Methyl PentaneC
Methyl Pentane H C
Methyl Pentane
These are different molecules, though!!!

21. So Now What?
Since two different molecules can’t have the same name, we must differentiate
If we look closely, though, the only difference between them is the position of the methyl group

22. Positioning 2- 3- So… Methyl Pentane Methyl Pentane C C
Here the methyl group is on the second carbon from the end
Here the methyl group is on the third carbon from the end
Again, the molecule on the left is 2-methyl pentane NOT 4-methyl pentane. Molecules don’t care about left or right so we start numbering from the closest side.
So…

23. Rules pt. 3 Identify the longest unbranched chain of carbons
Name it as normal
Identify the branch
Name it but give it a “–yl” suffix
Put the names of all branches first, then put name of longest chain
Put the number of the carbon the branch is on (start numbering from the closest single end)

24. Practice H C
2-methyl heptane H C
4-methyl octane H C
2-methyl hexane

25. Multiple Branches So far we’ve only had one branch
What happens when there are multple branches?
Just add a prefix to indicate the number of a particular type of branch

26. 2,2 dimethyl heptane Practice 2- methyl heptane 2- methyl
2-methyl, 2-methyl heptane
Sounds redundant
2,2 dimethyl heptane

27. More Practice 2, 6-dimethyl octane 3 ethyl-2,4-dimethyl pentane C C H
Technically you should but branches in alphabetical order but I won’t be that picky.
3 ethyl-2,4-dimethyl pentane

28. Multiple Bonds
So far, even with the cyclic structures we have dealt only with single bonds
Carbon can make multiple bonds to another carbon
This changes the name
Why?

29. Examine Structures C2H6 C2H4
Ethane- notice that each carbon has four bonds
What will happen to the structure if we double bond the two carbons?
Different structures need different names
C2H4 C H
Each carbon still has four bonds BUT now the hydrogens have changed!!

30. Alkenes Alkenes contain a double bond in the molecule.
The general formula for alkenes is
CnH2n

31. A little practice. What is the formula for an alkene with 4 carbons?
Draw the dot structure.
You can place the double bond between any two carbons since it wasn’t specified.

32. Wow, I can do this! The formula is C4H8 Butene The dot structure is
C – C = C – C

33. Alkynes Alkynes contain a triple bond in the molecule.
The general formula for alkynes is
CnH2n-2

34. Some more practice. What is the formula for an alkyne with 7 carbons?
Draw the dot structure.
You can place the triple bond between any two carbons since it wasn’t specified.

35. I am so smart! The formula is C7H12 Heptyne The dot structure is
C – C ≡ C – C – C – C – C

36. Naming molecules with multiple bonds
Name the molecule as normal
Change the suffix of the longest chain name
Double bonds = ene
Triple bonds = yne
Use numbering and prefixes for positioning and multiple multiple bonds.
Alkenes are molecules with double bonds
Alkynes are molecules with triple bonds
Alkanes are molecules only with single bonds

37. So…. C H C H C H
C2H6
C2H4
C2H2
ethane
ethene
ethyne

38. Practice H C
2-heptene H C
1-butene C H
3 methyl-1-pentene

39. Prefixes for #’s of groups Prefixes for #’s of CARBONS Suffixes
Single
Double
Triple
-ane
-ene
-yne 1- 2- 3- 4- 5- 6- 7- 8- 9-
10-
Mono Di
Tri
Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca 1- 2- 3- 4- 5- 6- 7- 8- 9-
10-
Meth
Eth
Prop
But
Penta
Hexa
Hepta
Octa
Nona
Deca
Branches use
-yl
Circles use
Cyclo-
Identify the longest chain (it must contain the double or triple bond if present)
Name it as normal
If Double or triple bonds are present use the correct suffix and identify the starting position with a number
Identify the branches
Name any branches by using carbon prefixes and –yl suffixes and identify their positions with a number
Add a prefix to indicate multiple branches using the groups prefixes

40. Is your arm sore yet?
Are you sick to death of writing all those carbons?
Even worse, are you sick of writing all those Hydrogens?
How about this…

41. Shorthand notation C H
Keep in mind that we have been ignoring the hydrogens for a long time.
Our names have been based entirely on the positioning of the carbons.
Each end and each “point” represents a carbon atom. The hydrogen atoms are assumed to be there.
So lets now ignore the hydrogens completely!

42. Is it that easy? H C C H

43. One More C H
Shorthand notation?
Name?
3-ethyl-2,4 dimethyl hexane

44. So is that it? Not even close!!
There are literally millions of different organic compounds.
What else can we do to make things more complicated?
Multiple bonds, rings, other atoms

45. Rings
Thus far we have dealt with chains that are straight or branched.
If hydrocarbons are long enough, one end can wrap around and link up with itself!
We call these cyclic hydrocarbons.

46. Cyclic Hydrocarbons Name the molecule as normal
Add the prefix cyclo- to the front of the name of the longest chain
Start numbering from the most “important” branch in the ring

47. Examples
Cyclohexane
Cyclooctane

48. More Examples Methyl cyclopentane 1,2 dimethyl cyclohexane
Note that a number is not needed on the first example.
Note that numbers are now needed to indicate position. It doesn’t matter, though which is 1 and which is 2
1,2 dimethyl cyclohexane

49. Try These 1 ethyl, 3 methyl cyclobutane
1 propyl, 3 methyl cylclohexane

50. How about in Shorthand? 2 pentene
Notice the two lines means the double bond is there!
2 pentene

51. Practice! Methyl propene 2,4-dimethyl-2-pentene
3-ethyl-2,4,4-trimethyl-1-pentene

52. AP Area
Unless you are a chemist, or in AP Chem you don’t need to worry about this

53. Tough Ones
2 methyl 1,3 butadiene
1,2 dimethyl-1,4 cyclohexadiene

54. Triples?
3, 3-dimethyl-1-butyne
1,4 cyclohexadiyne

55. So that’s it, right? Not even close, bud.
All this….all this was just for two elements, carbon and hydrogen!!
We haven’t even dealt with any of the others, yet.

56. Wait!! Don’t jump!! Get off that bridge.
It’s not that bad provided we arrange things in an organized fashion!

57. Functional Groups Nature has done us a favor.
There are many common groups that we can organized or file into different categories.
Then we can name them based on these categories.

58. Functional Groups
A group of atoms that, when added to a hydrocarbon chain, alter the chemical properties of the chain.
Just a few different functional groups to know…

59. Functional Groups Halogens Alcohols Ethers Aldehydes Ketones
Carboxylic Acids
Esters
Amines
R-F, R-Cl, R-Br, R-I
R-OH
R-O-R
R-COH
R-CO-R
R-COOH
R-COO-R
R-NH2

60. Functional Groups Nature has done us a favor.
There are many common groups that we can organize or file into different categories.
Then we can name them based on these categories.

61. Functional Groups
A group of atoms that, when added to a hydrocarbon chain, alter the chemical properties of the chain.
Just a few different functional groups to know…

62. Functional Groups Halogens Alcohols Ethers Aldehydes Ketones
Carboxylic Acids
Esters
Amines
R-F, R-Cl, R-Br,
R-OH
R-O-R
R-COH
R-CO-R
R-COOH
R-COO-R
R-NH2

63. What the heck is R? The R represents a chain of carbon atoms.
The the length of the chain is not significant.
It is important to understand where the functional group lies in relation to the chain of carbon atoms

64. Halides Fluorides, Chlorides, Bromides, and Iodides
Simply name the molecule as normal but add the prefix Fluoro, Chloro, Bromo, or Iodo as necessary

65. Halides Cl
2, 3 dichlorohexane I
3, 3 diiodo-1-pentene

66. Alcohols
R-OH
Name like normal except add an –ol suffix

67. Alcohols OH OH
2 propanol
1butenol OH C H
ethanol

68. Ethers
R-O-R
Name two “R” groups with –yl endings
End name in ether

69. Ethers are slightly soluble in water.
Uses of Ethers
Common solvents.
General anesthetic
Ethers are slightly soluble in water.

70. Ethers O
Dimethyl ether O
Ethyl methyl ether

71. Aldehyde
R-COH
This is a carbon to oxygen double bond with a hydrogen at the end.
Name as normal except use a “-al” suffix

72. Al Who?

73. Aldehydes C H O
butanal C H Cl O
3,3 dichloropentanal

74. Uses of Aldehydes Formaldehyde H2CO is used in the production of:
Dollar Bills
Ink used in books, magazines, and newspapers
Wrinkle-Free Clothing
Glues
Car bumpers

75. Ketones
R-CO-R
This is a carbon to oxygen double bond but in the center of a hydrocarbon chain rather than the end
Name as normal but give it a “-one” suffix

76. Uses of Ketones
Ketones are often used as stabilizers in paints and perfumes. They prevent the other chemicals from degrading or breaking down.
Acetone is found in nail polish remover.

77. Ketones C H O
propanone C H O
2 hexanone

78. Carboxylic Acids R-COOH or R-CO2H
This is a carbon to oxygn double bond with the same carbon single-bonded to an OH group.
Name as normal except give it the suffix “-anoic acid”.
HC2H3O2

79. Uses of Carboxylic Acids
Carboxylic Acids are relatively weak acids.
Acetic Acid is the main ingredient in vinegar

80. Carboxylic Acids Butananoic acid 3-Fluoropropanoic acid C H OH O C H F

81. Esters
R-COO-R
This is a carbon to oxygen double bond with a carbon to oxygen single bonded to another single bonded carbon
Name by given secondary branch “-yl” suffix and main branch “-anoate” suffix.

82. Esters methyl pentanoate Methyl Pentanoate Secondary Branch
Main Branch C H O
methyl
pentanoate
Methyl Pentanoate

83. Esters C H O
Butyl propanoate C H O
Methyl hexanoate

84. Amines R-NH2 Name the “R” group or groups with “-yl” endings
Add the word “amine”

85. Amines C H N
Methyl amine C H N
Dimethyl amine

86. Summary Cl R Halide OH R Alcohol R O Ether H R C Aldehyde O R C Ketone
Carboxylic Acid O O R C
Ester
NH2 R
Amine

87. Summary - “-ane” Alkanes Alkenes Alkynes Halides Alcohols Ethers
Aldehydes
Ketones
Carboxylic Acids
Esters
Amines
- “-ane”
= “-ene”
≡ “-yne”
R-X “-o”
R-OH “-ol”
R-O-R “-yl ether”
R-COH “-al”
R-CO-R “-one”
R-COOH “-anoic acid”
R-COO-R “-yl” “-anoate”
R-NH2 “-yl amine”