IUPAC Nomenclature of Organic Compounds

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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IUPAC NOMENC!ATURE O" ORGANIC COMPOUN#S IUPAC – IUPAC – International Union of Pure and Applied Chemistry C!ASSI"ICATION O" "UCNTIONA! GROUPS "OR PURPOSES O" NOMENC!ATURE NAME $HEN USE# NAME $HEN USE# "UNCTIONA! GROUP STRUCTURE AS PRE"I% AS SU""I% &PARENT' &SU(STITUENT' Principal Group Carboxylic acid -COOH -oic acid carboxy RIN-COOH -carboxylic acid

O

O

Carboxylic anhydrides

-oic anhydride

O Carboxylic esters  Acid halides halides  Amides Nitriles  Aldehydes  Aldehydes (etones  Alcohols Phenols )hiols  Amines Imines

RIN RIN-! -!C" C"O# O#-O -O-C -C!" !"O# O#--!C"O#OR RIN-!C"O#OR -!C"O#% RIN-!C"O#% -!C"O#NH& RIN-!C"O#NH& -C'N RIN-C'N -!C"O#H RIN--!C"O#H C"O -OH -OH -*H -NH& "NH

,enene  Al$enes  Al$ynes  Al$anes

-car -carbo boxy xyli lic c anhy anhydr drid ide e -oate -carboxylate -oyl halide carbonyl halide -amide -carboxamide -nitrile -carbonitrile -al -carbaldehyde -one -ol -ol -thiol -amine -imine

oxo formyl oxo hydroxy hydroxy mercapto + sulfanyl amino imino

-benene

phenyl

-ene -yne -ane

al$enyl al$ynyl al$yl

C"C C'C C-C

al$oxycarbonyl halocarbonyl halocarbonyl amido cyano

Su)ordinate Group .thers *ulfides Halides Nitro  Aides 1iao •

-OR -*R -/0 -Cl0 -,r0 -I -NO& N"N"N "N"N

al$oxy al$ylthio halo nitro aido diao

)he principal functional 2roups are listed in order of decreasin2 priority3 subordinate functional 2roups ha4e no established priority order5

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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COMPONENTS O" AN ORGANIC COMPOUN# NAME !OCANTS + PRE"I%ES + PARENT + SU""I% !OCANTS + numbers that tell 6here the substituents are located on the main chain or rin2 PRE"I% + parts that identify 6hat substituents are located on the main chain or rin2 PARENT + part that identifies the sie of the parent chain SU""I% + part 6hich identifies the principal functional 2roup class to 6hich the molecule belon2s Su)tituent + any other 2roup attached to the carbon chain other than hydro2en GENERA! STEPS AN# RU!ES IN NAMING ORGANIC COMPOUN#S 75 /ind the lon2est carbon chain containin2 the principal functional 2roup and assi2n it as the parent chain5 In case for a presence of t6o or more functional 2roups0 the hi2hest priority functional 2roup 6ill be chosen for the parent chain and the rest 6ill simply be substituents5 &5 1etermine the type and number !8uantity# of the substituents attached on the parent carbon chain5 95 Use prefixes di0 tri0 tetra0 etc to indicate the number !8uantity# of similar substituents5 :5 *tart assi2nin2 numbers for each carbon in the parent chain be2innin2 at the terminal carbon nearest the principal functional 2roup or the first branch point !in al$anes and al$yl halides#5 ;a$e sure to assi2n the 5 1etermine the position !carbon number# of all the substituents in the main+parent chain5 ?5 Use comma to separate numbers and use dash+hyphen to separate numbers and 6ords5 @5 Arran2e the names of the substituents in alphabetical order !excludin2 the prefixes li$e di0 tri0 tetra3 sec and tert#3 only iso and neo are considered in alphabetiation and they are not separated by a dash5 5 =rite the name of the compound accordin2 to the format abo4e5 E,ample

B 

@

?

:

>

B 

9

@

?

:

>

9 &

& 7

?-ethyl-:-isopropyl-@-methyl-&-nonene

7

:

?-ethyl-:-isopropyl-@-methyl-&-nonen--yne

O

? >

7

H

& 9

:-methyl-7-cyclopentene

cyclohexanecarbaldehyde

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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A. NAMING A!/ANES 75 /ind the parent carbon5 a5 /ind the lon2est continuous chain of carbon atoms and use the name of that chain as the parent name CH&CH9 CH9CH&CH&CH CH9

the lon2est chain has ? carbons0 so this is hexane

b5 If t6o chains of e8ual len2th are present0 choose the one 6ith the 2reater number branch points as the parent CH9

CH9 >

:

9

?

&

>

?

CH9CH CH CH&CH&CH9

CH9CH CH CH&CH&CH9 7

:

9

CH&CH9

CH&CH9

&

7

hexane 6ith t6o substituents and NO) hexane 6ith one substituent &5 Number the atoms in the main chain be2innin2 at the end nearer the first branch point5 7

@ ?

&

>

9

>

?

9

&

@ •

:

:

and NO)

7

C9 is the first branch point and not C:

95 Identify and number the substituents5 B

A > @

*ubstituents On C90 CH &CH9 On C:0 CH 9 On C@ CH 9

?

>

:

9

7

9

?

&

7

:

*ubstituents On C&0 CH9 On C90 CH9 On C90 CH&CH9 

!9-ethyl# !:-methyl# !@-methyl#

&

!&-methyl# !9-methyl# !9-ethyl#

:5 =rite the name as a sin2le 6ord5 Use hyphens to separate number-6ord prefixes and commas to separate numbers5 If t6o or more different side chains are present0 cite them in alphabetical order5 If  t6o or more identical side chains are present0 use one of the prefixes di-0 tri-0 tetra-0 and so forth5 1o not use these prefixes in alphabetiin25 CH9

CH&CH9 CH9CH&CH&CH CH9

9-methylhexane

B 9

:

>

?

CH9CH CH CH&CH&CH9 7

&

A

CH&CH9

9-ethyl-&-methylhexane

@

?

>

:

7

9 &

90@-diethyl-:-methylnonane

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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SOME A!/Y! GROUPS USE# IN IUPAC NAMING

isopropyl

sec-butyl

isobutyl

tert-butyl

isopentyl

neopentyl

(. NAMING CYC!OA!/ANES 75 Count the number of carbon atoms in the rin20 and add the prefix cyclo- to the name of the correspondin2 al$ane5 If a substituent is present on the rin20 the compound is named as an al$ylsubstituted cycloal$ane5 If the number of carbon in the chain is 2reater than the number of carbon in the rin20 then0 the compound has to be named as a cycloal$yl substituted al$ane5

CH9

methylcyclopentane

cyclohexylpentane

&5 /or substituted cycloal$anes0 start at a point of attachment and number around the rin25 If t6o or  more substituents are present0 be2in numberin2 at the 2roup that has alphabetical priority and proceed around the rin2 so as to 2i4e the second substituent the lo6est number5

CH9

CH9

*

*

3 2

0 1

0

CH9

1,3-dimethylcyclohexane

2 1

NOT

CH9

1,5-dimethylcyclohexane

CH9

CH9 *

0

* 1

3

-

-

CH&CH9

2

1

2

1-ethyl-2-methylcylcopentane

NOT

CH&CH9

0

2-ethyl-1-methyl-cyclopentane

NAMING CIS AN# TRANS ISOMERISM IN CYC!OA!/ANES H H9C

H

H

H9C

H H

CH9

H

NO) .DUA< )O

trans-709-dimethylcyclopentane • •

CH9

cycloal$anes are isomers of al$enes cycloal$anes also has 2eometric isomers cis and trans

H

H

cis-709-dimethylcyclopentane

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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C. NAMING A!/ENES 75 Name the parent carbon5 It is the lon2est carbon chain containin2 the double bond and name the compound usin2 the suffix –ene5 H9C

CH&

H

CH9CH&CH&

H

 pentene

and NO) hexane because the ? C does not contain the double bond

&5 Number the carbon atoms5 ,e2in numberin2 at the end nearer the double bond5 If the double bond is e8uidistant from the t6o ends0 be2in numberin2 at the end nearer the first branch point5 )his rule ensures that the double bond carbons recei4e the lo6est numbers CH9

CH9CH&CH&CH CHCH9 3

2

1

-

0

CHCH&CH9

H9C   CH CH

*

*

0

-

1

2

3

95 =rite the full name5 Number the substituents accordin2 to their position in the chain and list them alphabetically5 Indicate the position of the double bond by 2i4in2 the number of the first al$ene carbon5 If more than one double bond is present0 2i4e the position of each and use one of the suffixes –diene0 -triene0 and so on5 CH9

CH9CH&CH&CH CHCH9 3

1

2

-

0

H9C   CH CH

*

*

&-hexene or hex-&-ene

1

0

1

2

3

&-methyl-9-hexene or &-methylhex-9-ene

H9C 2

-

CHCH&CH9

CH& -

0

CH9CH&CH&

H *

H

*

&-ethyl-7-pentene

-

1 0

&-methyl-709-butadiene

:5 Cycloal$enes are named in similar 6ay0 but because there is no chain end to be2in from0 number the cycloal$enes so that the double bond is bet6een C7 and C& and so that the first substituent has a lo6 number as possible5 If there is only one double bond0 it is not necessary to specify the position of the double bond in the name because it is al6ays bet6een C7 and C& CH9

CH9

CH9

7-methylcyclohexene

H&C

methylene 2roup

70:-cyclohexadiene

H&C

CH

4inyl 2roup

70>-dimethylcyclopentene

H&C CH C H& allyl 2roup

CH&"CH& ethylene

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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NAMING CIS AN# TRANS IN A!/ENES ClCH&CH&

H

CH9

H

CH9

ClCH&CH&

H

cis->-chloro-&-pentene

 

H

trans->-chloro-&-pentene

NAMING TRISU(STITUTE# AN# TETRASU(STITUTE# A!/ENES T4e E56 #eignation7 Ca4n8Ingold8Prelog Rule CH9

H H

H9C

CH&

CH

H9C H&C

H9C

HO

,r 

H

CH9  

CH&OH

H

H

(3E)-9-methyl-709-pentadiene

O

(3E)-7-bromo-&-isopropyl709-butadiene

 

(2Z)-&-hydroxymethyl-&-butenoic acid

#. NAMING A!/YNES *ame rules in namin2 al$anes and al$enes apply in here0 but usin2 the suffix –yne5 Compounds containin2 both double and triple bonds are called enynes !not ynenes#5 Numberin2 of the hydrocarbon chain starts from the end nearer the first multiple bond0 6hether  double or triple5 If there is a choice in numberin20 double bonds recei4e lo6er numbers than triple bonds5 • •

9

?-methyl-9-octyne

-

1

3 2

0

7-hepten-?-yne

:

3

1

*

*

0

2

9

;

:-methyl-@-nonen-7-yne

E. NAMING AROMATIC COMPOUN#S R

R

RE

monosubstituted disubstituted phenyl 2roup benene benene phenyl and benyl are used if benene is considered as a substituent

benene •

benyl 2roup

NAMING AROMATIC COMPOUN#S 75 ;onosubstituted ,enene same as namin2 a hydrocarbon except that benene is the parent name •

,r 

bromobenene benylbromide

NO&

nitrobenene

CH&CH&CH9

propylbenene

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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E. NAMING AROMATIC COMPOUN#S &cont' &5 Al$yl substituted benenes !arenes# depend on the sie of the al$yl 2roup5 If the al$yl substituent has more than ? carbons0 the compound is named as phenyl-substituted al$ane

&-phenylheptane or heptan-&-ylbenene 95 1isubstituted benenes use a5 OR)HO !o# 70 & relationship b5 ;.)A !m# 70 9 relationship c5 PARA !p# 70 : relationship

% NO&

ortho ,r 

meta H9C

para

CH9

,r 

,r 

ortho-dibromobenene

meta-bromonitrobenene

para-dimethylbenene

:5 ,enenes 6ith more than & substituents are named by numberin2 the position of each substituent so that the lo6est possible numbers are used5 )he substituents are listed alphabetically5 CH9 0

,r 

3

2

NO&

2

-

1

*

O&N

3

:-bromo-70&-dimethylbenene

*

1

*

O&N

0

3 2

Cl

&-chloro-70:-dinitrobenene

NO& -

1

0

NO&

&0:0?-trinitrotoluene !)N)#

Common Name of Some Aromatic Compound CH9

toluene

OH

phenol

O

NH&

aniline

O

H

benaldehyde

CH9

acetophenone

cumene

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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E. NAMING AROMATIC COMPOUN#S &cont' Common Name of Some Aromatic Compound

O

CH9

CN

OH CH9

benonitrile

benoic acid

ortho-xylene

NO& H9C

 

nitrobenene •

OH

p-cresol

naphthalene

)he monosubstituted benenes in the table can be used as parent name5

OH *

,r 

,r 

3

-

2

0

O Cl

OH

1

&0?-dibromophenol

m-chlorobenoic acid

". NAMING A!/Y! HA!I#ES 75 /ind the lon2est carbon chain and name it as the parent5 )reat the halo2en as a substituent5 If a multiple bond is present0 the parent chain must contain it5 &5 Number the carbons of the parent chain be2innin2 at the end nearer the first substituent0 re2ardless of 6hate4er it is0 al$yl or halo5 Assi2n each substituent a number accordin2 to its position on the chain5 If there are substituents that are e8uidistant0 be2in numberin2 at the end nearer the substituent 6ith alphabetical priority5

*

CH9

CH9

-

1

0

2

,r

CH9

3 9

CH9

,r 

>-bromo-&0:-dimethylheptane

&-bromo-:0>-dimethylheptane

95 =rite the name5 it4 Common Name

O

O

O H9C

CH9

CH9

acetone acetophenone

benophenone

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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H. NAMING A!#EHY#ES AN# /ETONES &cont' Su)tituent Naming in Alde4=de and /etone

O R

O

O

C

H9C

acyl 2roup

O

C

H

O

C

 Ar 

formyl

acetyl

C

C

aroyl benoyl

•

Occassionally0 the doubly bonded oxy2en is considered a substituent0 and the prefix oxo- is used5

O

O

H9C

O

methyl-9-oxohexanoate I. NAMING CAR(O%Y!IC ACI#S AN# #ERI?ATI?ES CAR(O%Y!IC ACI#S7 RCOOH *imple open-chain carboxylic acids are named by replacin2 the terminal –e of the al$ane name 6ith –oic acid5 )he –COOH carbon !carboxyl 2roup carbon# is al6ays numbered C75 •

O

O

HO *

O OH

•

0

1

2

3

9

: OH

O

HO propanoic acid

-

:-methylpentanoic acid

9-ethyl-?-methyloctanedioic acid

 Alternati4ely0 compounds that ha4e a –COOH 2roup bonded to a rin2 are named by usin2 the suffix –carboxylic acid5 In this alternati4e system0 the carboxylic acid carbon is attached to C7 on the rin2 but is not itself numbered5 O  

3 *

2

COOH *

OH

-

2 1

0

,r 

&-bromocyclohaxanecarboxylic acid •

1

0

7-cyclopentenecarboxylic acid

Carboxylic acids 6ere amon2 the first or2anic compounds to be isolated and purified0 thus there are a lar2e number of acids 6ith common names5 *ystematic names must be used on most carboxylic acids but formic acid and acetic acid are already established names and are 6idely used5

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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I. NAMING CAR(O%Y!IC ACI#S AN# #ERI?ATI?ES &cont' ACI# HA!I#ES7 RCO%  Acid halides are named by identifyin2 first the acyl 2roup and then the halide5 )he acyl 2roup name is deri4ed from the acid name by replacin2 the –ic acid endin2 6ith –yl0 or the –carboxylic acid endin2 6ith –carbonyl5 •

O

O

O

H9C

,r 

Cl

Cl

acetyl chloride

benoyl bromide

cyclohexanecarbonyl chloride

ACI# ANHY#RI#ES7 RCOOCOR@  Anhydrides from simple carboxylic acids and cyclic anhydrides from dicarboxylic acids are named by replacin2 the 6ord acid 6ith anhydride5 •

O O

H9C

O O

O O

O

O

O

CH9

acetic anhydride

benoic anhydride

succinic anhydride

AMI#ES7 RCONH Amides 6ith an unsubstituted –NH & 2roup are named by replacin2 the –oic acid or –ic acid endin2 6ith –amide0 or by replacin2 the –carboxylic acid endin2 6ith –carboxamide5 •

O O

O NH&

H9C

CH9!CH&#:

NH&

acetamide •

NH&

hexanamide

cyclopentanecarboxamide

If the nitro2en atom is substituted0 the amide is named by first identifyin2 the substituent 2roup and then the parent5 )he substituents are preceded by the letter N to identify them as bein2 directly attached to nitro2en5 O NH

N CH9

O

N-methylpropanamide

CH&CH9

CH&CH9

N0N-diethylcyclohexanecarboxamide

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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I. NAMING CAR(O%Y!IC ACI#S AN# #ERI?ATI?ES &cont' ESTERS7 RCOOR@ *ystematic names for esters are deri4ed by first 2i4in2 the name of the al$yl 2roup attached to oxy2en and then identifyin2 the carboxylic acid0 then0 the –ic acid endin2 is replaced by –ate5 •

O

O

O

O

O

O

ethyl acetate !ethyl ester of acetic acid#

CH9 O

CH9 CH9

O

dimethyl malonate !dimethyl ester of malonic acid#

tert-butylcyclohexanecarboxylate

NITRI!ES7 R8CN Compounds containin2 the -C'N functional 2roup are called nitriles5 *imple open chain nitriles are named by addin2 –nitrile as a suffix to the al$ane name0 6ith the nitrile carbon numbered C75 •

C N

:-methylpentanenitrile •

;ore complex nitriles are named as deri4ati4es of carboxylic acids by replacin2 the –ic acid or – oic acid endin2 6ith –onitrile0 or by replacin2 the –carboxylic acid endin2 6ith –carbonitrile5 In this system0 the nitrile carbon atom is attached to C7 but is not itself numbered5

CN C

N

CH9 CH9

CH9C'N acetonitrile

benonitrile

&0&-dimethylcyclohexanecarbonitrile

COMP!E% NOMENC!ATURE

& 7

9

:

>

?

@

:-!7-methylethyl#heptanes :-isopropylheptane :-!propan-&-yl#heptane

:-!707dimethylethyl#octane :-tert-butyloctane :-!&-methylpropan-&-yl#octane

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

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COMP!E% NOMENC!ATURE 28et4=l838&08met4=lpentan8-8=l'undecane NOTE7 In the substituent at carbon ?0 find the lon2est carbon chain al$yl 2roup5 )he lon2est is a >-carbon al$yl 2roup 6ith a methyl 2roup at carbon 9 of the substituent5 )he &-yl indicates that the hydro2en of the al$yl 2roup has been remo4ed from carbon & of the substituent5 -8)romo8053598trimet4=l8-8octene

,r  CN

NOTE7 )he first substituents are ambi2uous5 )hey are both number & startin2 on either end5 Remember if there is ambi2uity in the numberin20 assi2n the lo6est number in alphabetical order5 -8acet=l818met4=l)enBonitrile NOTE7 Nitrile is the hi2her priority o4er $etone5 )a$e note of the term acetyl !see table abo4e in Namin2 (etones#

O

O

O

08form=l828met4=l)enBoic acid

OH

H

NOTE7 Carboxylic acid is the principal 2roup5 )a$e note of the term formyl !see table abo4e in Namin2 Aldehydes#

O

?

>

:

9

&

38met4=l898o,o4eptanoic acid 7 OH

@ H

O

O OH

O

NOTE7 )he aldehyde is part of the chain0 thus0 instead of usin2 formyl0 oxo has been used5

-8&0528dimet4=lp4en=l'propanoic acid NOTE7 )he lon2est carbon chain contains the carboxylic acid and not the benene rin25 )he rin2 is merely a substituent of the principal chain5

?-benyl-&-octanone

;c;urry G5 !&#5 Or2anic Chemistry5 ,roo$s+Cole N

ORGANIC CHEMISTRY IUPAC Nomenclature of Organic Compound

*3

*olomons0 )5=5 and /ryhle C5 !&#5 Or2anic Chemistry5 Gohn =iley and *ons NG