Nomenclature LabNomenclature LabExerciseExercise

In this lab we will learn the basic In this lab we will learn the basic rules for drawing and naming rules for drawing and naming

organic structures.organic structures.

Functional Groups:Functional Groups:AlkanesAlkanes Hydrocarbons that have only single Hydrocarbons that have only single

bonds between all of the atoms.bonds between all of the atoms.

AlkenesAlkenes Hydrocarbons with AT LEAST one Hydrocarbons with AT LEAST one double bond.double bond.

AlkynesAlkynes Hydrocarbons with AT LEAST one Hydrocarbons with AT LEAST one triple bond.triple bond.

Cyclic Cyclic CompoundsCompounds

Carbon compounds that form a circle.Carbon compounds that form a circle.

AlcoholsAlcohols Compounds that contain hydroxyl Compounds that contain hydroxyl (OH) groups.(OH) groups.

AldehydesAldehydes Compounds that contain a carbonyl Compounds that contain a carbonyl group (an oxygen double bonded to a group (an oxygen double bonded to a carbon) bonded to an end carbon.carbon) bonded to an end carbon.

KetonesKetones Are like aldehydes except their Are like aldehydes except their carbonyl group is in the middle of the carbonyl group is in the middle of the molecule.molecule.

OH

H

O

O

HydrocarbonsHydrocarbons are named according to the longest continuous chain of are named according to the longest continuous chain of carbons in the molecule (rather than the total # of carbon atoms). The carbons in the molecule (rather than the total # of carbon atoms). The

longest chain is called the parent compound.longest chain is called the parent compound.

4-ethylnonane

3-ethylheptane

Single bonds end in “ane”, Single bonds end in “ane”, 1 or more double bonds end in “ene”, 1 or more double bonds end in “ene”,

triple bonds end in “yne”.triple bonds end in “yne”.

hexane

3-hexene

2-butyne

2,4-heptadiene

Carbon branches are named by their Carbon branches are named by their lengthlength and and positionposition on on the main chain. The branch is named by using the parent the main chain. The branch is named by using the parent

name with the suffix “yl”.name with the suffix “yl”.

3,4-dimethyl 4,5-diethyloctane octane

Carbon chains are numbered from left to right or right to left. Carbon chains are numbered from left to right or right to left. You may You may not change directionnot change direction once started. (This rule is once started. (This rule is

used to allow you to describe where changes are occurring.) used to allow you to describe where changes are occurring.) The numbering always starts from the direction that will The numbering always starts from the direction that will

allow the branch numbers to be the lowest.allow the branch numbers to be the lowest.

4-propylnonane….NOT 6-propylnonane

Names of the Names of the substituent groupssubstituent groups (any atom or group of (any atom or group of atoms that substitutes for a hydrogen atom in an organic atoms that substitutes for a hydrogen atom in an organic

molecule) are placed in alphabetical order before the name of molecule) are placed in alphabetical order before the name of the parent chain regardless of their position number.the parent chain regardless of their position number.

4-ethyl-2-methylnonane

Multiple branchesMultiple branches are named in order of where the branches are named in order of where the branches occur, by the number of branches of that type, and given a occur, by the number of branches of that type, and given a

name for the size of the branch.name for the size of the branch.

4,7-diethyl-5,6-dimethyldecane

HyphensHyphens (“ (“--”) are always used to separate numbers from ”) are always used to separate numbers from names and names and commascommas (“ (“,,”) are used to separate numbers from ”) are used to separate numbers from themselves. The last alkyl group is prefixed to the name of themselves. The last alkyl group is prefixed to the name of

the parent compound to form one word.the parent compound to form one word.

4,7-diethyl-5,6-dimethyldecane

Halogen substitutionsHalogen substitutions (Fluorine, Chlorine, Bromine, and (Fluorine, Chlorine, Bromine, and Iodine) of hydrogen are named in the same manner as Iodine) of hydrogen are named in the same manner as hydrocarbon branches. The prefixes are shown below.hydrocarbon branches. The prefixes are shown below.

3-bromo-6-chloro-4-fluorononaneBr

F Cl

Carbons that form rings start with the prefix “cyclo-”.Carbons that form rings start with the prefix “cyclo-”.

cyclopropane cyclohexane cyclobutane

cyclopropene cyclopentadiene

When there are substituents, numbers are required and are When there are substituents, numbers are required and are assigned so that the carbons bearing the substituents have the assigned so that the carbons bearing the substituents have the lowest numbers listed in alphabetical order. Remember that lowest numbers listed in alphabetical order. Remember that

multiple bondsmultiple bonds in the parent chain get the lowest number in the parent chain get the lowest number beforebefore substituentssubstituents..

2-bromo-4-ethyl-1-methylcyclohexane

3-bromo-1-ethyl-4-methylcyclohexene

Br

Br

BenzenesBenzenes – are a special type of cyclic compound because – are a special type of cyclic compound because the alternating single and double bonds make it a very stable the alternating single and double bonds make it a very stable

molecule.molecule.If the benzene ring is the parent compound, the molecule’s If the benzene ring is the parent compound, the molecule’s name will have the suffix “name will have the suffix “benzenebenzene”. If the benzene ring is ”. If the benzene ring is

the substituent it is given the prefix “the substituent it is given the prefix “phenylphenyl-”.-”.

ethylbenzene 2-phenylnonane

Benzene rings are numbered in such a way that the substituents are Benzene rings are numbered in such a way that the substituents are given the lowest possible numbers alphabetically. For di-given the lowest possible numbers alphabetically. For di-

substituted benzene rings a special designation is used. If the substituted benzene rings a special designation is used. If the substituents are in the 1,2 position it is know as “substituents are in the 1,2 position it is know as “orthoortho” or “” or “oo”. If ”. If

they’re in the 1,3 position it is known as “they’re in the 1,3 position it is known as “metameta” or “m”, and if ” or “m”, and if they’re in the 1,4 position it is “they’re in the 1,4 position it is “parapara” or “p”.” or “p”.

o-dimethylbenzene

m-dimethylbenzene

p-dimethylbenzene

AlcoholsAlcohols (carbons with an “-OH” group) end with the suffix (carbons with an “-OH” group) end with the suffix “-ol”. In other regards, they use the same rules as for “-ol”. In other regards, they use the same rules as for

branches.branches.

butanol 2-propanol

OHOH

Alcohols are classified as primary (1), secondary (2), or tertiary (3), depending on the number of carbon groups bonded to the carbon bearing the –OH group.

IUPACname

Common namebutyl

alcoholisopropyl alcohol

An alcohol in which two hydroxyl groups are present is named An alcohol in which two hydroxyl groups are present is named with the suffix -with the suffix -dioldiol,, one containing three hydroxyl groups is one containing three hydroxyl groups is

named with suffix- named with suffix- trioltriol, , etc. etc. In these names, the final In these names, the final ––ee of the parent alkane name is retained of the parent alkane name is retained

for pronunciation reasons.for pronunciation reasons.

OH OH OH OHOH OH OH OH

│ │ │ │ │ │ │ │

CHCH33-CH-CH-CH-CH22-OH-OH CHCH22-CH-CH-CH-CH22

IUPAC name

Common name

1,2-propanediol

propylene glycol

1,2,3-propanetriol

glycerin or glycerol

AldehydesAldehydes (carbons ending with an “=O” (carbonyl) group) end (carbons ending with an “=O” (carbonyl) group) end with the suffix “-al”. In other regards, they use the same rules as with the suffix “-al”. In other regards, they use the same rules as

for branches.for branches.

3-methylhexanal 4,5-dicholor-3-methylheptanal

KetonesKetones (carbons with a “=O” group in the middle) end with (carbons with a “=O” group in the middle) end with the suffix “-one”. In other regards, they use the same rules as the suffix “-one”. In other regards, they use the same rules as for branches. (Remember Aldehydes at the end, Ketones in for branches. (Remember Aldehydes at the end, Ketones in

the middle!)the middle!)

4-heptanone 3,5-heptadione

O O O

Functional groups:Functional groups:Carboxylic AcidsCarboxylic Acids These compounds contain a special These compounds contain a special

combination of both a carbonyl group combination of both a carbonyl group and a hydroxyl group attached to the and a hydroxyl group attached to the same end carbon.same end carbon.

EthersEthers Have two carbons attached directly to Have two carbons attached directly to the same oxygen atom. the same oxygen atom.

EstersEsters Are like ethers but one of the carbons Are like ethers but one of the carbons attached directly to the ether carbon is attached directly to the ether carbon is also a carbonyl group.also a carbonyl group.

AnhydridesAnhydrides Are like esters but both carbons Are like esters but both carbons attached to either side of the oxygen are attached to either side of the oxygen are also carbonyl groups.also carbonyl groups.

O

CH

H

H

C

O

OH

O

O

O

O O

More functional groups:More functional groups:AminesAmines Compounds in which nitrogen Compounds in which nitrogen

is bonded to carbon.is bonded to carbon.

AmidesAmides Are like carboxylic acids but Are like carboxylic acids but the hydroxyl group is the hydroxyl group is replaced by nitrogen.replaced by nitrogen.

ThiolsThiols These compounds are just These compounds are just like alcohols, but instead of like alcohols, but instead of oxygen, they have sulfur.oxygen, they have sulfur.

ON

N

SH

Carboxylic AcidsCarboxylic Acids ( carbons with a “-OOH” group) end with ( carbons with a “-OOH” group) end with the suffix “-oic acid”. the suffix “-oic acid”.

hexanoic acid

OH

O

• Notice the structure: they the structure: they must occur at the end of a chainmust occur at the end of a chain. .

• The hydrogen attached to the oxygen is the proton source for the acid. The hydrogen attached to the oxygen is the proton source for the acid.

• The C=O group is generally known as a “carbonyl” group. You will see the The C=O group is generally known as a “carbonyl” group. You will see the carbonyl group again as part of other functional groups in the following carbonyl group again as part of other functional groups in the following sections.sections.

• Main chain numbering always starts at the carboxylic acid functional group Main chain numbering always starts at the carboxylic acid functional group end!end!

O

H

5-ethyl-3-methyloctanoic acid

EthersEthers (Carbons with an “-O-”group in the middle, as in C-O-C’), are named (Carbons with an “-O-”group in the middle, as in C-O-C’), are named for their two parts. for their two parts. - It begins with the core of the smaller hydrocarbon, then “oxy”, then the full - It begins with the core of the smaller hydrocarbon, then “oxy”, then the full name of the larger hydrocarbon. name of the larger hydrocarbon. - An acceptable alternate (common name) has the smaller, then the larger - An acceptable alternate (common name) has the smaller, then the larger hydrocarbon group cores, each followed by the suffix “-yl”, followed by the hydrocarbon group cores, each followed by the suffix “-yl”, followed by the word “ether”. word “ether”. - In other regards, they use the same rules as for branches.- In other regards, they use the same rules as for branches.

ethoxybutane isopropoxypentane

ethyl butyl ether isopropyl pentyl ether

O

O

IUPAC name

Common name

Structure

EstersEsters are named for their two parts. The core of the first part has are named for their two parts. The core of the first part has the suffix “-yl” and with the second part (with the double bonded the suffix “-yl” and with the second part (with the double bonded O) having the suffix “-oate”. In other regards, they use the same O) having the suffix “-oate”. In other regards, they use the same

rules as for branches.rules as for branches.

ethyl hexanoate

O

O

“Parent acid” “Parent” alcohol

O

O

AminesAmines are hydrocarbons containing an ammonia group (-NH are hydrocarbons containing an ammonia group (-NH22) )

and are named as branches coming off nitrogen, followed by the and are named as branches coming off nitrogen, followed by the suffix “amine”.suffix “amine”.

Amines can be primary, secondary, and tertiaryAmines can be primary, secondary, and tertiaryIn secondary and tertiary amines, the prefix In secondary and tertiary amines, the prefix N-N- is used for each is used for each

substituent of the nitrogen atomsubstituent of the nitrogen atom

N,N-dimethylbutanamine

N

NH2

propanamine

If more than one amine group is present, specify the position of each group, use the prefix di, and retain the final –e of the hydrocarbon chain.

NH2H2N 1,3-propanediamine

IUPAC name

Common namedimethylbutylamine propylamine

AmidesAmides are the nitrogen replacements of –OH groups in carboxylic acids. are the nitrogen replacements of –OH groups in carboxylic acids. The nitrogen does not need to be terminal. These compounds are named The nitrogen does not need to be terminal. These compounds are named

as derivatives of carboxylic acids. as derivatives of carboxylic acids. In other words, they’re named as if they were carboxylic acids, except the In other words, they’re named as if they were carboxylic acids, except the

“-oic acid” ending is replaced with “-amide”.“-oic acid” ending is replaced with “-amide”.The group attachment to a nitrogen is indicated by the capital letter The group attachment to a nitrogen is indicated by the capital letter N-N-

N-methylbutanamide Butanamide

NH

O

NH2

O

1

2

3

4

Hierarchy of namingHierarchy of naming

Not all chemical compounds have only one type of functional Not all chemical compounds have only one type of functional group. For those compounds with mixed groups, for group. For those compounds with mixed groups, for

example, a molecule that is both an amine as well as a example, a molecule that is both an amine as well as a carboxylic acid, a system of priorities must be established. carboxylic acid, a system of priorities must be established.

These priorities and names associated with them are found in These priorities and names associated with them are found in the following table.the following table.

Hierarchy of Naming TableHierarchy of Naming Table

PrioritPriorityy

ClassificationClassification Functional Functional GroupGroup

Suffix if the Suffix if the highest highest priority.priority.

Prefix if a Prefix if a Lower PriorityLower Priority

11 Carboxylic Carboxylic AcidAcid

-oic acid-oic acid --

22 AldehydeAldehyde -al-al Oxo-Oxo-

33 KetoneKetone -one-one Oxo-Oxo-

44 AlcoholAlcohol -OH-OH -ol-ol Hydroxy-Hydroxy-

55 AmineAmine -NH-NH22 -amine-amine Amino-Amino-

OH

O

H

O

O

Hierarchy examples:Hierarchy examples:

5—amino-5-hydroxy-4-methylpentanoic acid

7-amino-5-hydroxyheptanal

N

H

O

OH

OH

H

N

O

H

OH

H

H

O

OH

O

H2N

3-amino-2-oxopropanoic acid