Functional Groups
A functional group is a small group of atoms that lend
characteristic properties to the molecule
Properties of the molecule are dictated by the functional
groups; allows for systematic study of organic molecules
Halides: R-X where R is any alkyl group, and X a halogen
CH3Cl - chloromethane
C6H5Cl - chlorobenzene
Cl
Synthesis: radical chain reaction between an alkane and a
halogen
CH4 + Cl2
Cl2
hn or heat
hn or heat
CH3Cl + HCl
2Cl•
•Cl + CH4  HCl + •CH3
•CH3 + Cl2  CH3Cl + •Cl
Alcohols: R-OH hydroxyl functional group
Nomenclature - use the suffix “ol”
CH3-CH2-OH ethanol
CH3-CH2-CH2OH 1-propanol
H 3C
C
H2
CH2
C
H2
OH
1-butanol
(1o alcohol)
Primary alcohol
OH
H 3C
C
H2
CH
CH3
2-butanol
(2o alcohol)
Secondary alcohol
OH
H 3C
C
CH3
CH3
2-methyl-2-propanol
(3o alcohol)
Tertiary alcohol
Presence of OH group allows hydrogen bonding
As the C chain becomes longer the OH group becomes less
important
Charge distribution in
ethanol; red indicates
negative charge
Synthesis of alcohols
Hydrolysis of a alkyl halide with a strong base
OH- + CH3Br  CH3OH + BrAddition across a double bond
CH2=CH2 + H2O
300 - 400oC
60 - 70 atm
CH3CH2OH
Phenols: hydroxyl group attached directly to an aromatic
ring
OH
Phenol (C6H5OH)
weak acid, Ka = 1 x 10-10; stability of the
phenolate ion (C6H5O-)
Oil of thyme
Oil of clove
Ethers: R - O - R
C2H5 - O - C2H5
C6H5 - O - C2H5
Synthesis:
H SO
2 R-OH
2
4
diethylether
ethylphenylether
R - O - R + H2O
Kinetics vs thermodynamics
CH3-CH2-OH
+
CH3-CH2-OH
H2SO4
H2SO4
140oC
180oC
2CH2=CH2 + 2 H2O
CH3-CH2-O-CH2-CH3 + H2O
Aldehydes and Ketones
C
O
carbonyl group
C
O
aldehyde
C
O
H
R
R
ketone
R
H
HCHO: formaldehyde
C
O
H
H3 C
CH3CHO: acetaldehyde
C
O
H
H3 C
CH3COCH3: dimethlyketone (acetone)
C
H3 C
O
Properties of aldehydes and ketones differ because of the
aldehyde H atom
CH3CH2OH
1o alcohol
ethanol
(CH3)2CHOH
2o alcohol
2-propanol
O2, catalyst,
CH3CHO
aldehyde
acetaldehyde
high temperatures
O2, catalyst,
high temperatures
(CH3)2CO
dimethylketone
almond and cherries
vanilla
cinnamon
Carboxylic acids: -COOH functional group
O
C
OH
O
HCOOH - formic acid (ant venom)
H
C
OH
O
CH3COOH - acetic acid (vinegar)
H3C
C
OH
Carboxylic acids hydrogen bond - “dimers”
Synthesis
Catalytic oxidation of aldehydes
CH3CHO
O2, Mn2+
CH3COOH
R-COO- R’
Esters:
O
R
C
O
R'
O
O
H3C
C
CH2CH3
OH
H
O
acetic acid + ethanol
H3C
+
C
OCH2CH3
ethylacetate
H2O
Fats (solids) and oils (liquids) are triesters formed from
glycerol and three carboxylic acids (fatty acids)
Tristearin: animal fatty acid tri-esters
CH2OHCHOHCH2OH + 3 CH3(CH2)16COOH
glycerol
stearic acid
Saturated - C-C single bonds
Unsaturated - one (mono-unsaturated) or more
(polyunsaturated) C=C bonds
Amines:
N
H
H
H
N
H
R
primary amine (1o)
H
N
H
R secondary amine (2o)
R'
N
R
ammonia
R'
R" tertiary amine (3o)
CH3NH2
(CH3)2NH
(CH3)3N
C6H5NH2
methylamine
dimethylamine
trimethylamine
NH2
aniline
N
Amines are bases:
NicH2+(aq) + 2 NH3(aq) 
Nic(aq) + 2 NH4+(aq)
Synthesis of amines
a) Naturally occurring
b) NH3 + CH3Cl  CH3NH2 + HCl
CH3
N
nicotine
Amino acids: carboxylic acid containing an amine group
Glycine: NH2CH2COOH
+
H3NCHCOOH
R
cationic form
predominant
in acidic
solutions
- H3O+
+ H3O+
+
H3NCHCOO
R
dipolar form zwitterion
- H3O+
+ H3O+
H2NCHCOO
R
anionic form
predominant
in basic
solutions
-
R'
Amides: -CONH2- group
C
N
O
R
H
Formed by reaction between NH3 or 1o or 2o amine and acid
O
H3 C
O
CH2CH3
C
O
H
H
NH
H3 C
C
+ H 2O
NHCH2CH3
O
H
C
HO
C
H2
N
+
H HO
O
O
O
C
C
H2
NH2
C
HO
C
H2
N
H
C
C
H2
NH2
+ H2O
glycine
+
glycine
diglycine + H2O
Proteins: polypeptides with CONH linkage between
amino acids
http://www.cryst.bbk.ac.uk/pps97/course/section3/helix.pdb