2. Basics of naming an organic cmpd:
• Find the longest continuous carbon chain
– This is the parent chain
– Use a root prefix to indicate # of C’s
• Ex: meth, eth, prop, etc.
• Number the C’s from the end nearest the side
groups
– Side grps should be on lowest combination of C’s
• Name the side groups (alphabetical order if >1)
• Number the side groups
– # corresponds to the C the side group is attached to
3. Root Prefixes for Organic Cmpds.
Meth = 1 Oct = 8
Eth = 2 Non = 9
Prop = 3 Dec = 10
But = 4
Pent = 5
Hex = 6
Hept = 7
4. I. Saturated Hydrocarbon
1. Straight Chain HC
a) n – root + ane
b)
c) Try this:
CH3
CH2
CH2
CH2
CH3
CH3
CH2
CH2
CH3
2. Branched Chain HC
a) # + side group + root + ane
b) Branch = if derived from alkane drop –ane and
add –yl
n-pentane
n-butane
5. Alkyl Side Groups
Isopropyl-CH3 C CH3
H
Sec-butyl-
CH3 C CH3
CH3
Tert-butyl-
(AKA: t-butyl)
Phenyl-
Methyl-
C
H
C
H
H
HH
Ethyl-
C
H
C
H
H
HH
C
H
H
Propyl-
C
H
H
H
CH3
CH
CH3
CH3
6. I. Saturated Hydrocarbon
2. Branched Chain (cont’d)
c) Use di, tri, tetra, etc. to describe multiple side
groups of the same kind (ex. triethyl-)
d) Arrange names of side groups in alphabetical
order
2,2-dimethylbutane 2, 2, 3-trimethylpentane
CH3 C CH2
CH3CH3
CH3
CH3 C H2C
CH3CH3
CH3 CH2 CH3
7. Structural Isomers…
• Same molecular formulas but different
arrangements of atoms (different
structural formulas)
– Ex. butane and methyl propane are isomers
8. II. Unsaturated HC
1. Naming Alkenes – double bonds
a) # + side group + # + root + ene
b) Number chain so double bond gets lowest #
Try this:
Side groups:
Root Chain:
Location of bond:
Family:
4-methyl-2-pentene
CH3
CH2
CH3
CH3
4-methyl
Pent-
2nd
carbon
-ene
Hint: # the C’s so the
double bond gets
lowest value
9. II. Unsaturated HC
2. Naming Alkynes – triple bonds
a) # + side group + # + root + yne
b) Number chain so triple bond gets lowest #
Try this:
Side groups:
Root Prefix:
Location of bond:
Family:
6-methyl
Hept-
3
-yne
6-methyl-3-heptyneCH3 H2C
CH2 C C
CH3
CH2
CH3
10. III. Cyclic Molecules *
• # + side group + Cyclo + root + family suffix
– If side groups, number ring so side group gets
lowest #
– If double bond, number it to get lowest #
• Try this:
Side groups:
Root Chain:
Family:
1-ethyl-2-methyl
Cyclopent-
-ane
1-ethyl-2-methylcyclopentane
H2C
CH
CH2CH2
H2C
CH3
CH3
Remember: These are
listed alphabetically
11. Other Stuff
Substituent Name
-Br Bromo-
-F Fluro-
-Cl Chloro-
-I Iodo-
-NO2 Nitro-
-OH Hydroxy-
(used if not
alcohol)
Other things that could be
attached to chain:
Cis- and Trans-
cis-2-butene trans-2-butene
Name These:
Cis-3-hexenetrans-3-hexene
12. IV. Alcohols (R-OH) *
1. # + side group + root + # + ol
2. -OH should get lowest number
3. See rules from I-III for additional info.
Try This:
H2C
CH
CH2CH2
H2C
CH3
OH
Side groups:
Root Chain:
Location of -OH:
Family:
Cyclopentan-
1
-ol
2-ethylcyclopentanol
2-ethyl
Can omit the 1 in the name. It is assumed
to be on C #1 if no # listed.
13. IV. Alcohols (R-OH)
Alternative Names:
2-ethylcyclopentanol
2-ethyl-1-cyclopentanol
2-ethylcyclopentan-1-ol
Draw: 2-ethyl-3-cyclopenten-1-ol
14. V. Aldehydes * -CHO
1. Root = longest C chain that contains
aldehyde group
2. Number C’s beginning at aldehyde group
(this is always son C #1)
3. Aldehyde group requires no # in name
4. Root = ends in –al Ex. ethanal
5. Name side group according to previous
rules
15. V. Aldehydes (examples)
Side groups:
Root Chain:
Family:
2-bromo-
Hexan-
-al
2-bromohexanal
Side groups:
Root Chain:
Family:
3-hydroxy, 2-ethyl
Butan-
-al
2-ethyl-3-hydroxybutanal
16. VI. Ketones *
1. Number C’s so keto group gets
lowest #
2. Root = longest C chain w/keto group
on it
3. Use # to indicate location of keto
group
4. Root ending = -one
5. Ex. propanone
17. VI. Ketones (examples)
Side groups:
Root Chain:
Location of Keto:
Family:
3-methyl, 5-methyl
Heptan-
4
-one
3, 5-dimethyl-4-heptanone
Side groups:
Root Chain:
Location of double bond:
Location of Keto:
Family:
N/A
penten-
3
-one
2
Pent-3-en-2-one
18. VII. Carboxylic Acids* -COOH
1. Carboxy group always on C #1
2. Root = longest C chain w/carboxy
group on end
3. Suffix = -oic acid
4. Ex. Ethanoic acid
19. VII. Carboxylic Acid (examples)
Side groups:
Root Chain:
Location of double bond:
Family:
N/A
Hexen-
2
-oic acid
Cis-2-Hexenoic acid
Side groups:
Root Prefix:
Family:
N/A
Hexan-
-dioic acid
Hexanedioic acid
20. VIII. Ethers* R-O-R’
1. General form of Name: alkyl alkyl ether
2. Examples:
side chain #1 Side chain #2
Dimethyl ether
Methyl propyl ether
Methyl isopropyl ether
21. IX. Esters* R-COO-R’
• Formed from dehydration rxn between alcohol
and carboxylic acid
(alcohol – ol + yl) (carboxylic acid –oic acid +
oate)
• Example:
R1 R2 R1 R2C
O
+
O
COH OH +O H2O
carboxylic
acid
alcohol
ester
methyl ethanoate
23. X. Amines *
1. Name each R group but change to –yl
ending (i.e. if R1 is CH3 group = methyl)
2. Name all side groups in alphabetical order
3. Followed by word “amine”
• Ex. Ethyl methyl amine
4. If more than one side group is same, use
di, tri, etc. to indicate how many
• Ex. diethyl amine
R1 N R2
R3
