Systematic Nomenclature of Organic Compounds
1. Find the longest continuous carbon chain (parent chain).
a. If there is a functional group (double or triple bond, alcohol etc) it must be on or
part of the parent chain.
b. If there is a ring in the compound either the ring itself or the non-ringed chain
will be the parent chain but never both combined.
c. If there are two or more chains of equal length, pick the one with the greatest
number of substituents.
2. Number the carbons in the parent chain.
a. If there is a functional group, assign it the lowest possible position. If the
functional group gets the same position from either end then consider the lowest
number for the substituents. If there is a functional group on a ring, assign it
position 1. Double bonds in a ring are at positions 1 and 2.
b. If there is multiple functional groups the priority is carbonyls > alcohols > carboncarbon multiple bonds > amines. If you have a carbon-carbon double bond and a
carbon-carbon triple bond, go in the directions that gives the lowest possible
positions. If both directions give the same numbers, the double bond will take
priority.
c. If there are no functional groups, give the substituents the lowest possible numbers.
If you get the same numbers from either end assign the alphabetically first
substituent the lowest number.
3. Naming your compound.
a. If the compound has a specific configuration or geometry (cis/trans, E/Z or R/S)
indicate this first.
b. The first name is the substituents in alphabetical order. Prefixes that denote a
number (di, tri, sec, tert etc.) are not alphabetized. List the position(s) on the
parent chain and denote how many with a Greek prefix. If a substituent is on a
nitrogen the letter N is used to denote the position in lieu of a number. Hyphens
are placed between letters and number whereas commas between two numbers.
c. The last name of the compound is the parent chain. The stem of the name
indicates the length of the parent chain and the suffix reflects the type of
compound. If your parent chain is a ring add the prefix cyclo. If your parent
chain had a functional group indicate the position if it’s not obvious.
# of
C’s
1
2
3
4
5
6
7
8
9
10
Stem
meth
eth
prop
but
pent
hex
hept
oct
non
dec
11
12
undec dodec
Type of
Compound
Alkane
Alkene
Alkyne
Alcohol
Amine
Suffix
ane
ene, diene,
triene
yne, diyne,
triyne
anol, enol,
ynol
anamine,
enamine,
ynamine
Substituent Names
CH3
H3C
H3C
CH3
methyl
butyl
ethyl
CH3
propyl
hexyl
CH3
H3C
pentyl
CH3
H3C
CH3
H3C
CH3
CH3
isopropyl
CH3
CH3
sec-butyl
isobutyl
CH3
H3C
CH3
H3C
H3C
tert-butyl
CH3
benzyl
CH2
CH2
vinyl
cyclopentyl
allyl
cyclohexyl
phenyl
H3C
CH3
F
Cl
Br
I
fluoro chloro bromo iodo
O
CH3
methoxy
O
O
O
H3C
CH3
ethoxy
CH3
H3C
propoxy
isopropoxy