Naming Organic Compounds
Vladimíra Kvasnicová
Carbon skeleton of organic compounds
methane
ethane
hexane
3-methylpenthane
Organic compounds can be cyclic
 C6: many conformations in space (free rotation of C-C;
the most stable at room temperature: CHAIR conformation)
http://www.chemistry.nmsu.edu/studntres/c
hem539/answers/chexane_chair.jpg
http://cat.middlebury.edu/~che
m/chemistry/students/williamso
n/stewart/chairboat.jpg
Substituents
in cyclic hydrocarbons
 geometric isomerism = the same sequential arrangement
of atoms but different arrangement in space
trans = E-
cis = Z-
http://www.arthistoryclub.com/art_history/Geometric_isomerism
Double bond cannot rotate
 example of geometric isomers:
http://www.gunthersclass.com/24_10.jpg
NAMING ORGANIC COMPOUNDS
Important prefixes:
1
meth-
2
eth-
3
prop-
4
but-
5
pent-
6
hex-
7
hept-
mono
di
tri
tetra
penta
hexa
hepta
8
9
10
11
12
13
20
oct-
non-
dec-
octa
nona
deca
undec dodec tridec
icosa-
Valence of elements in organic compounds
• CARBON
always tetravalent
• NITROGEN
trivalent
• OXYGEN
bivalent
• SULPHUR
bivalent
• HYDROGEN
monovalent
• HALOGENS
monovalent
Types of bonds:
1) single (-ane)  saturated hydrocarbons
2) double (-ene) or triple (-yne)
 unsaturated hydrocarbons
3) conjugated (planar cycle: arens)
Hydrocarbon rests (alkyls, R)
CH4
methane
→
CH3methyl
→
-CH2methylene
CH3-CH3
ethane
→
CH3-CH2ethyl
→
-CH2-CH2ethylene
CH2=CH2 →
ethene
CH2=CHvinyl
→
-CH=CHvinylene
(„ethylene“)
(ethenyl)
Aromatic hydrocarbons
=
=
=
=
= benzene
= naphthalene
=
= anthracene
=
=
=
=
phenanthrene
=
pyrene
=
benzopyrene
Hydrocarbon rests of arens (aryls, Ar)
→
=
=
=
benzene
phenyl
=
CH3
CH2
CO
COOH
→
→
toluene
= biphenyl
benzyl
benzoic acid
benzoyl
Important derivatives of benzene
• methylbenzene = toluene
• dimethylbenzenes = xylenes (o-, m-, p-)
 1,2-dimethylbenzene = o-xylene
 1,3-dimethylbenzene = m-xylene
 1,4-dimethylbenzene = p-xylene
• vinylbenzene = styrene (→ polystyrene, PS)
Important heterocyclic compounds
NITROGEN in the cycle
OXYGEN in the cycle
• pyrrole
• furan
• pyridine
• tetrahydrofuran
• pyrimidine
• pyran
• purine
• tetrahydropyran
• indole
• imidazole
DERIVATIVES OF HYDROCARBONS
The name of the compound is derived from
the name of the basic unbranched hydrocarbon
• principal functional group
 type of the derivative  suffix
• other functional groups
→ expressed by special prefixes + locants
derivative
formula
prefix
suffix
carboxylic
- COOH
acid
sulfonic acid - SO3H
carboxy-
-oic acid
sulfo-
sulfonic acid
aldehyde
- CHO
formyl-
-al
ketone
= CO
oxo-
-one
alcohol
- OH
hydroxy-
-ol
thiol
- SH
sulfanyl-
-thiol
amine
- NH2
amino-
-amine
ether
-O-
R-oxy-
ether
sulfide
-S-
R-thio-
sulfide
halogen der. - F, -Cl, -Br, -I
halogen-
-
nitro der.
nitro-
-
- NO2
derivative
formula
prefix
suffix
carboxylic
- COOH
acid
sulfonic acid - SO3H
carboxy-
-oic acid
sulfo-
sulfonic acid
aldehyde
- CHO
formyl-
-al
ketone
= CO
oxo-
-one
alcohol
- OH
hydroxy- -ol
thiol
- SH
sulfanyl-
-thiol
amine
- NH2
amino-
-amine
ether
-O-
R-oxy-
ether
sulfide
-S-
R-thio-
sulfide
halogen der. - F, -Cl, -Br, -I
halogen-
-
nitro der.
nitro-
-
- NO2
derivative
formula
prefix
suffix
carboxylic
- COOH
acid
sulfonic acid - SO3H
carboxy-
-oic acid
sulfo-
sulfonic acid
aldehyde
- CHO
formyl-
-al
ketone
= CO
oxo-
-one
alcohol
- OH
hydroxy-
-ol
thiol
- SH
sulfanyl-
-thiol
amine
- NH2
amino-
-amine
ether
-O-
R-oxy-
ether
sulfide
-S-
R-thio-
sulfide
halogen der. - F, -Cl, -Br, -I
halogen-
-
nitro der.
nitro-
-
- NO2
DERIVATIVES OF HYDROCARBONS
The name of the compound is derived from
the name of the basic unbranched hydrocarbon
ALCOHOLS
R―OH
(R = alkyl)
• suffix: -ol (ethanol)
• suffix: -diol (ethane-1,2-diol, ethylene glycol)
• alkyl + alcohol (ethyl alcohol)
• primary, secondary, tertiary alcohols
• monofunctional / polyfunctional alcohols
THIOLS (MERCAPTANS)
R―SH
• suffix: -thiol (methanethiol) / -dithiol
• alkyl mercaptan (methyl mercaptan)
• alkyl hydrosulfide (methyl hydrosulfide)
PHENOLS
Ar―OH (Ar = aryl)
• common (trivial) names (phenol, cresols)
ETHERS
R1―O―R2
(R = alkyl or aryl)
• alkyl ether (ethyl methyl ether)
• alkoxyhydrocarbon (methoxyethane)
SULFIDES
R1―S―R2
(R = alkyl or aryl)
• alkyl sulfide (ethyl methyl sulfide)
ALDEHYDES
R―CHO
(R = H, alkyl or aryl)
• suffix: -al (methanal)
• carboxylic acid (trivial name) + aldehyde
(formic acid → formaldehyde)
• cycloalkane carbaldehyde
KETONES
R1―CO―R2
(R = alkyl or aryl)
• suffix: -one (propanone)
• alkyl ketone (dimethyl ketone)
• trivial names (acetone)
• diketones derived from arens: -quinone
AMINES
- derived from ammonia: H(s) replaced by alkyl(s)
• primary:
R―NH2
* alkylamine (methylamine)
* hydrocarbonamine (methanamine)
• secondary:
R1―NH―R2
* alkyl1(alkyl2)amine
ethyl(methyl)amine
* N-alkylhydrocarbonamine
N-methylethanamine
• tertiary:
R1―NR2―R3
* alkyl1(alkyl2)alkyl3amine
* alkyl1(alkyl2)hydrocarbonamine
• quarternary ammonium base: 4 alkyls-N+
* (multiple)alkylammonium (= cation)
e.g. tetramethylammonium-chloride
CATION
ANION
--------------------------------------------------------------+ trivial names (aniline)
AZO DYES
Ar1―N═N―Ar2
• hydrocarbon(larger one)azohydrocarbon
• azohydrocarbon (Ar1 = Ar2) (azobenzene)
R―NO2
NITROCOMPOUNDS
• prefix: nitro- (nitromethane)
SULFONIC ACIDS
R―SO3H
• hydrocarbonsulfonic acid
(benzenesulfonic a.)
CARBOXYLIC ACIDS
R―COOH
• suffix: -oic / -dioic acid
• trivial names!
• saturated / unsaturated
• mono-, di-, tri-carboxylic acids
• alpha () / omega () carbon
• - or n- fatty acids
• acyl / anion
The figure was adopted from: J.Koolman, K.H.Röhm / Color Atlas of Biochemistry, 2nd edition, Thieme 2005
Derivatives of carboxylic acids
1. substitutional derivatives
→ substitution in the chain of an acid
→ no change in the carboxyl group
2. functional derivatives
→ functional (carboxyl) group is changed
Derivatives of carboxylic acids
1. substitutional derivatives
→ substitution in the chain of an acid
1.1. HALOGEN DERIVATIVES
R(X)―COOH
• prefix: chloro-, bromo-, iodo-, fluoro1.2. HYDROXY DERIVATIVES
• prefix: hydroxy• trivial names!
R(OH)―COOH
1.3. OXO DERIVATIVES
R― (C═O)―COOH
• prefix: oxo- / keto• trivial names!
1.4. AMINO DERIVATIVES
R(NH2)―COOH
• prefix: amino• trivial names!
2. functional derivatives
→ functional (carboxyl) group is changed
2.1. SALTS
R―COO- M+ (M+ = metal cation)
• suffix: -ate / -oate
• -ic → -ate
/
-oic → -oate
• R―COO- = carboxylate (anion of c.a.)
• full name: cation carboxylate
(sodium acetate)
2.2. ESTERS
R1―O―C(O)―R2
• suffix: -ate
• R1―O― = rest of alcohol
• R1 = alkyl
• full name: alkyl carboxylate (methyl acetate)
2.3. ANHYDRIDES
R1―C(O)―O―C(O)―R2
• acid → anhydride
• (acetic acid → acetic anhydride)
• organic, organic-inorganic
2.4. AMIDES
R―C(O)―NH2
• suffix: -amide (ethanamide)
• -ic or –oic acid → -amide (acetamide)
• substituted –NH2 group: N-alkyl…amide
2.5. ACYLHALIDES R―C(O)―X X = halogen
• acyl name + halide (acetyl chloride)
2.6. NITRILES
R―CN
• hydrocarbon + suffix: -nitrile (ethanenitrile)
• alkyl cyanide (methyl cyanide)
Important chemical reaction of organic
compounds
1. substitution (= replacement)
CH4 + Cl2 → CH3Cl + HCl
2. addition (multiplicity of chemical bond is lowered)
CH2=CH2 + H2O → CH3-CH2-OH
3. elimination (new multiple bond is often formed,
small molecule is released)
CH3-CH2-OH → CH2=CH2 + H2O
4. rearrangement (= formation of an isomer)
CH2=C(OH)-COOH → CH3-C(O)-COOH
Important chemical reaction of organic
compounds
•
oxidation: oxygenation, dehydrogenation
•
reduction: hydrogenation
•
hydration /dehydration
•
esterification / ester hydrolysis
•
dissociation of carboxylic acids
•
aldol condensation of two carbonyl compounds
•
condensation reaction (= two molecules combine to
form larger molecule with elimination of a small molecule)