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/chem539/answers/chexane_chair.jpg

http://cat.middlebury.edu/~chem/chemistry/students/

williamson/stewart/chairboat.jpg

Substituentsin cyclic hydrocarbons

geometric isomerism = the same sequential arrangement of atoms but different arrangement in space

http://www.arthistoryclub.com/art_history/Geometric_isomerism

trans = E- cis = Z-

Double bond cannot rotate

example of geometric isomers:

http://www.gunthersclass.com/24_10.jpg

NAMING ORGANIC COMPOUNDS

Important prefixes:

1 2 3 4 5 6 7

meth- eth- prop- but- pent- hex- hept-

mono di tri tetra penta hexa hepta

8 9 10 11 12 13 20

oct- non- dec-undec

-dodec

-tridec

-icosa-

octa nona deca

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 → CH3- → -CH2-

methane methyl methylene

CH3-CH3 → CH3-CH2- → -CH2-CH2-

ethane ethyl ethylene

CH2=CH2 → CH2=CH- → -CH=CH-

ethene vinyl vinylene(„ethylene“) (ethenyl)

Aromatic hydrocarbons

= = = = benzene

= naphthalene=

= = anthracene

= =

= phenanthrene

= = pyrene

= benzopyrene

Hydrocarbon rests of arens (aryls, Ar)

→ = = =

=

benzene phenyl

= biphenyl

CH3

→

CH2

toluene benzyl

COOH

→

CO

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

• pyrrole

• pyridine

• pyrimidine

• purine

• indole

• imidazole

OXYGEN in the cycle

• furan

• tetrahydrofuran

• pyran

• tetrahydropyran

DERIVATIVES OF HYDROCARBONS

• principal functional group

type of the derivative suffix

• other functional groups

→ expressed by special prefixes +

locants

The name of the compound is derived from the name of the basic unbranched hydrocarbon

derivative formula prefix suffixcarboxylic acid

- COOH carboxy- -oic acid

sulfonic acid - SO3H 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. - NO2 nitro- -

derivative formula prefix suffixcarboxylic acid

- COOH carboxy- -oic acid

sulfonic acid - SO3H 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. - NO2 nitro- -

derivative formula prefix suffixcarboxylic acid

- COOH carboxy- -oic acid

sulfonic acid - SO3H sulfo- sulfonic acid

aldehyde - CHO formyl- -al

ketone = CO oxo- -one

alcohol - OH hydroxy- -olthiol - 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. - NO2 nitro- -

DERIVATIVES OF HYDROCARBONS

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

The name of the compound is derived from the name of the basic unbranched hydrocarbon

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)

NITROCOMPOUNDS R―NO2

• 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-, fluoro-

1.2. HYDROXY DERIVATIVES R(OH)―COOH

• prefix: hydroxy-• trivial names!

1.3. OXO DERIVATIVES R―

(C═O)―COOH

• prefix: oxo- / keto-

• trivial names!

1.4. AMINO DERIVATIVESR(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―CN • 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)