Organic Chemistry Nomenclature

Rules for naming organic compounds

prefix

what part of the name tells you about how many carbon atoms are present?

meth-

1 carbon

eth-

2 carbons

prop-

3 carbons

but-

4 carbons

pent-

5 carbons

hex-

6 carbons

hept-

7 carbons

oct-

8 carbons

non-

9 carbons

dec-

10 carbons

undec-

11 carbons

dodec-

12 carbons

tridec-

13 carbons

tetradec-

14 carbons

pentadec-

15 carbons

hexadec-

16 carbons

heptadec-

17 carbons

octadec-

18 carbons

nonadec-

19 carbons

eicos-

20 carbons

Infix

what part of the name tells you about the nature of the carbon-carbon bonds?

-an-

all single bonds

-en-

one or more double bonds

-yn-

one or more triple bonds

suffix

what part of the name tells you the class of compound?

-e

hydrocarbon

-ol

alcohol

-al

aldehyde

-amine

amine

-one

ketone

-oic acid

carboxylic acid

parent name

the longest carbon chain

substituent

a group bonded to the parent chain

alkyl group

a substituent derived by removal of a hydrogen from an alkane; given the symbol R- (Radical) and suffix -yl

find the longest continuous carbon chain

what is the first step in nomenclature?

base alkane name

what does the number of carbons in the longest chain determine?

most substituents

if there are two possible chains with the same number of carbons, use the chain with the ____ ____________.

pink

what chain would you use? (pink or green)

the end closest to the first attached group

where do you start counting the parent chain?

at the end nearest to the second branch point

if you are counting your carbons and both ends have a substituent at the same distance, where do you start?

alkyl group

each substituent is given a name and a number. how should you name the substituent groups attached to the longest chain? keep in mind, they would be a group with an H removed.

1-methylethyl (isopropyl)

what is the name of this substituent group?

2-methylpropyl (isobutyl)

what is the name of this substituent group?

1-methylpropyl (sec-butyl)

what is the name of this substituent group?

1,1-dimethylethyl (tert-butyl)

what is the name of this substituent group?

the end that gives the lower number to the substituent encountered first

if there are two or more identical substituents, which end should you number from?

use a prefix to indicate how many times it appears

if there are two or more identical substituents, how should you indicate that?

2,4-dimethylhexane

name this molecule

list them in alphabetical order

what do you do if there are two or more different substituents?

3-ethyl-5-methylheptane

name this molecule

number, alkyl, parentheses

what if there is a complex substituent (a branch has a branch)?

• _____ the carbons from the point of attachment

• name the branch off the branch as an ____ group

• _______ are used around the complex branch name

(1-ethyl-2-methylpropyl)

name this complex substituent

(1,1,3-trimethylbutyl)

name this complex substituent

cycloalkanes

what is it called when there is a ring of carbon atoms?

no need; lower alphabetical; lowest, alphabetical order

naming cycloalkanes:

• if only one substituent, __ ____ to give it a number

• if two substituents, number from the substituent of _____ _________ order

• if three or more substituents, number to give them the ______ set of numbers and then list substituents in ________ ____

1,1-diethyl-3-methylcyclopentane

name this molecule

T

(T/F) If an alkyl chain contains more carbons than an attached cycloalkane, then name it as an alkane with a cycloalkyl substituent.

2-cyclopentylheptane

name this molecule