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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)