Download CHEM 109A CLAS Nomenclature of Organic Compounds

CHEM 109A
CLAS
Nomenclature of Organic Compounds - KEY
1. Name the following compounds.
a.
b.
c.
2,3-Dimethyl-pentane
5-sec-Butyl-5-isopropyl-2-methyl-nonane
4-Isopropyl-2,5-dimethyl-heptane
Cl
d.
e.
f.
1-Chloro-2-methyl-4-propyl-cyclopentane
Cyclobutyl-cyclohexane
OH
1-Methyl-cyclopentanol
Br
g.
OH
5-Bromo-hexan-3-ol
Page 1 of 7
CHEM 109A
CLAS
Nomenclature of Organic Compounds - KEY
OH
h.
2-Methyl-propan-1-ol
-or- isobutyl alcohol
NH 2
3-aminohexane
-or- 3-hexanamine
-or- 1-Ethyl-butylamine
i.
NH2
j.
tert-Butylamine
-or- 2-amino-2-methylpropane
-or- 2-methyl-2-propanamine
2. Draw the following compounds.
a. 3-chloro-2,3-dimethylcyclopentanol
OH
Cl
3-chloro-2,3-dimethylcyclopentanol
b. 4,5-diethyl-3-iodo-4-octanamine
I
NH2
4,5-diethyl-3-iodo-4-octanamine
c. sec-butyl chloride
Cl
sec-butyl chloride
d. tert-butyl isobutyl ether
O
tert-butyl isobutyl ether
Page 2 of 7
CHEM 109A
CLAS
Nomenclature of Organic Compounds - KEY
e. neopentyl alcohol
OH
neopentyl alcohol
f. dimethyl ether
O
dimethyl ether
g. ethane
ethene
h. methanal
O
methanal
i. ethanoic acid
HO
O
ethanoic acid
j. isobutyl amine
H 2N
isobutylamine
Additional Information:
List of Common Functional Groups on inside back cover of text or my website
Steps for naming compounds
5 parts to a name…
Stereoisomerism Substituents Parent Hydrocarbon Unsaturation Functional Group
Stereoisomerism – indicates whether double bonds are cis/trans, E/Z and stereo
centers (R, S). Will be covered in another handout.
Substituents – groups coming off of the parent hydrocarbon.
Parent Hydrocarbon – main/longest chain of carbons that includes functional groups
> double bond(s) > triple bond(s) when appropriate.
Unsaturation – identifies any double or triple bonds
-ane → all single bonds
-ene → 1 or more double bonds
-yne → 1 or more triple bonds
Functional Group – functional group after which the compound is named.
Page 3 of 7
CHEM 109A
CLAS
Nomenclature of Organic Compounds - KEY
Alkanes (CnH2n+2): –ane, [Alkenes (CnH2n): -ene, Alkynes (CnH2n-2): -yne later in
109A and beginning of 109B]
1. Determine the # of C atoms in the longest continuous chain (parent chain) –
Watch for branches!
Table 2.1 Nomenclature of Straight-Chain Alkanes
# of carbons Stem Name of alkane Molecular formula or skeletal
structure of alkane
1
meth2
eth3
prop4
but5
pent6
hex7
hept8
oct9
non10
dec11
undec12
dodec2. Number the chain in the direction that gives any substituent a lower number.
(Numbers are not used in common names)
a. If numbering in both directions gives the same number to a substituent,
number in the direction that gives the lowest number to the alphabetically
first substituent.
Table 2.2 Names of Common Alkyl Groups (same as previous Table 2.1, only ending
has been changed to –yl)
Name
Chemical Formula
Methyl
H3C
H 3C
Ethyl
Propyl
C
H2
H2
C
H3 C
C
H2
H3C
CH
Isopropyl
CH3
Butyl
H2
C
H2
C
H 3C
Isobutyl
C
H2
CH 3
CH
H 3C
C
H2
Page 4 of 7
CHEM 109A
CLAS
Nomenclature of Organic Compounds - KEY
H2
C
CH
H 3C
sec-butyl
CH3
H 3C
CH 3
tert-butyl
C
H 3C
Pentyl
H2
C
H3C
H2
C
C
H2
CH 3
Isopentyl
H2
C
CH
C
H2
H2
C
H 3C
Hexyl
C
H2
H2
C
H 3C
Isohexyl
C
H2
C
H2
CH 3
H2
C
CH
H3C
H2
C
C
H2
C
H2
3. Substituents are listed in alphabetical order, preceded by the # of the C they are
attached to.
Prefixes, as well as sec and tert are ignored when alphabetizing, but iso and
cyclo are NOT.
a. Numbers and words are separated by hyphens and numbers are separated
by commas.
b. Prefixes are used when there is more than one of the same substituent
i. di, tri, tetra.
4. If there are two chains with the same number of Cs, choose the one with the most
substituents as the parent chain.
EX. 2,3-dimethylhexane
2,3-dimethylhexane
2,2,4-Trimethyl-hexane
Cycloalkanes: cyclo- -ane
1. Ring is parent unless the substituent has more Cs than the ring
2. If the ring has
a. Only one substituent do NOT number it (it will always be assumed to be
on C#1)
b. Two substituents, cite them alphabetically and give the number 1 position
to the first substituent.
Page 5 of 7
CHEM 109A
CLAS
Nomenclature of Organic Compounds - KEY
c. Three or more substituents, the substituent given the number 1 is the one
that results in a second substituent getting as low a number as possible.
i. If two substituents have the same low number, the ring is
numbered in a direction that gives the third substituent the lowest
possible number.
1,1-dimethylcyclohexane
EX.
1-Ethyl-2-methyl-cyclopentane
1,1-Dimethyl-cyclohexane
Alkyl Halides: -ide
1. Name of the alkyl group followed by the name of the halogen with –ide ending.
2. Alkyl halides are named as substituent alkanes. The prefixes for the halogen end
with “o” (fluoro, chloro, bromo, iodo).
Can be classified as 1o, 2o or 3o (primary, secondary or tertiary) if the C attached to
the halide is attached to 1, 2 or 3 other Cs, respectively.
Cl
EX. 2-fluoropropane
F
Cl
2-Fluoro-propane
isopropyl fluoride, 2o
1-Chloro-4-methyl-pentane
isohexyl chloride, 1o
Table 2.2 Names of Common Alkyl Groups (same as previous Table only ending has
been changed to –yl)
Ethers: (R-O-R, R-O-R') –oxy or ether
Common Name:
1. Name the two alkyl substituents in alphabetical order, followed by the word
“ether”.
Systematic Name:
2. Name the ether as an alkane with an RO substituent (replace the –yl ending with –
oxy).
Page 6 of 7
CHEM 109A
CLAS
Nomenclature of Organic Compounds - KEY
EX.
ethoxy ethane
O
O
Ethoxy-ethane
O
1-Isopropoxy-3-methyl-butane
-or- diethyl ether -or- ethyl ether
Alcohols: -ol
Common Name:
1. Name the alkyl group to which the OH group is attached, followed by the word
“alcohol”.
Systematic Name:
2. Replace the –e ending of the parent hydrocarbon with the suffix –ol.
Cl
EX. 5-methyl-3-hexanol
HO
Cl
OH
5-Methyl-hexan-3-ol
-or- 5-methyl-3-hexanol
HO
4-Chloro-cyclohexanol
Amines: -amine
Common Name:
1. Name the alkyl groups bonded to the nitrogen in alphabetical order, followed by
the word “amine” – the entire name is written as one word.
Systematic Name:
2. A number denotes the carbon to which the nitrogen is attached (can appear before
the name, or before the “amine”).
3. Replace the –e ending of the parent hydrocarbon with the word “amine”.
4. Substituents – whether attached to the nitrogen or to the parent hydrocarbon – are
listed in alphabetical order, and a number or and “N” is assigned to each one.
EX.
N
N,N-dimethyl-3-pentamine
N,N-diethyl-1-propamine –or- diethylpropylamine
N
Page 7 of 7