Nomenclature of Alkanes (Flashcards)

Vocabulary flashcards covering key concepts, rules, prefixes, substituents, and cycloalkane nomenclature from the lecture notes.

suffix -ane

Suffix used for alkanes

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

Longest linear chain

The main uninterrupted chain chosen as the base for naming; it is the longest possible and can be numbered in either direction.

Monosubstituted alkane

An alkane with a single substituent; substituents use the suffix -yl.

yl suffix

Suffix for alkyl substituents (methyl, ethyl, etc.) derived from the base alkane.

3-methylheptane

An example of a monosubstituted alkane where a methyl group is on carbon 3 of a seven-carbon chain.

Multiply-substituted alkane

An alkane with two or more substituents on the main chain.

tie for longest chain

If multiple longest chains exist, choose the one with the most substituents.

multiplicity prefixes di-, tri-, tetra-

Prefixes used to indicate more than one substituent of the same type (dimethyl means 2 methyl groups, trimethyl means 3 methyl groups attached to the main carbon chain)

alphabetical order of substituents

Substituents are listed in alphabetical order in the name; prefixes di/tri/tetra are not considered for ordering.

Halogen substituents

Fluoro-, chloro-, bromo-, iodo-; substituents derived from halogens.

isopropyl (iPr)

An alkyl substituent (CH3-CH-CH3)

sec-butyl (sBu)

Secondary-butyl substituent;

isobutyl (iBu)

Branched butyl substituent;

tert-butyl (tBu)

Tertiary-butyl substituent;

neopentyl (neop)

A branched-chain alkyl group derived from neopentane, consisting of a five-carbon chain with a central carbon attached to two methyl groups.

alphabetization note for iso/neo

In alphabetizing, count 'iso' and 'neo' but ignore 'sec' and 'tert' as separate letters.

cycloalkanes

Nomenclature for cyclic alkanes uses the prefix 'cyclo-' before the base name (cycloalkane). Everything else is the same as linear alkanes in terms of substituent placement and numbering.

one substituent on cycloalkane exception

If only one substituent is present on a cycloalkane, a number is not required.

ring can be substituent when chain longer

If the side chain has more carbons than the ring, the ring is named as a substituent on the chain.

direction of numbering can vary

The longest chain can be numbered in either direction; choose the direction with the lowest locants.

lowest-locants rule

When numbering substituents, select the numbering that yields the smallest set of locants, read from left to right.