Download Nomenclature of Organic Compounds

CHEM 109A
CLAS
Nomenclature of Organic Compounds
1. Name the following compounds.
a.
e.
f.
OH
Br
b.
OH
g.
OH
h.
NH 2
c.
Cl
i.
NH2
j.
d.
2. Draw the following compounds.
a. 3-chloro-2,3dimethylcyclopentanol
b. 4,5-diethyl-3-iodo-4octanamine
c. sec-butyl chloride
d. tert-butyl isobutyl ether
Steps for naming compounds
5 parts to a name…
Stereoisomerism Substituents Parent Hydrocarbon
Stereoisomerism –
Substituents –
Parent Hydrocarbon –
Unsaturation –
-ane →
-ene →
-yne →
Functional Group –
e.
f.
g.
h.
i.
j.
neopentyl alcohol
dimethyl ether
ethene
methanal
ethanoic acid
isobutyl amine
Unsaturation
Functional Group
Page 1 of 4
CHEM 109A
CLAS
Nomenclature of Organic Compounds
Alkanes (CnH2n+2):
, Alkenes (CnH2n):
, Alkynes (CnH2n-2):
1. Determine the # of C atoms in the longest continuous chain (parent chain) –
Watch for branches!
# of carbons Stem Name of alkane Molecular formula 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.
3. Substituents are listed in alphabetical order.
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, sec and tert are ignored in alphabetizing.
ii. iso, neo and cyclo (INC) are NOT ignored in alphabetizing.
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
Cycloalkanes:
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
b. Two substituents, cite them alphabetically and give the number 1 position
to the first substituent.
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.
Page 2 of 4
CHEM 109A
CLAS
Nomenclature of Organic Compounds
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.
Alkyl Halides:
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).
Cl
EX. 2-fluoropropane
Table 2.2 Names of Common Alkyl Groups
Name
Chemical Formula
Methyl
Ethyl
Propyl
Isopropyl
Butyl
Isobutyl
sec-butyl
tert-butyl
Pentyl
Isopentyl
Hexyl
Isohexyl
Page 3 of 4
CHEM 109A
CLAS
Nomenclature of Organic Compounds
Ethers:
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).
EX.
ethoxy ethane
O
Alcohols:
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
Amines:
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
Page 4 of 4