LOGO
Lecture 11:
Organic compounds II : Functional groups and the
molecules of life
Spring 2014
Course lecturer
Jasmin Šutković
6th May 2014
Contents
International University of Sarajevo
1.
2.
3.
4.
5.
6.
7.
Arenes
Alcohols
Ethers
Aldehydes
Ketones
Carboxylic acid
Molecules of life
•
•
•
•
Proteins
Carbohydrates
Lipids
Nucleic acids
Arenes – cycle hydrocarbons
 Most arenes with a single six-membered ring are volatile
liquids
 Benzene, C6H6, is the simplest aromatic hydrocarbon,
and it was the first one recognized.
Arenes are Compounds containing both aliphatic and
aromatic parts.
Alkyl-benzenes
Alkenyl-benzenes
Alkynyl-benzenes
Etc….
Volatility ?
Volatility is a measure of a substance's vapor
pressure and it's tendency to vaporize.
 Polycyclic aromatic hydrocarbons are lipophilic,
meaning they mix more easily with oil than water
 Example of Poly-aromatic hydrocarbons is
Hexa-peri-hexabenzocoronene- one of the most
widespread organic pollutants.
 Its toxic to humans !
Aromatic VS. Aliphatic
 In organic chemistry, compounds composed
of carbon and hydrogen are divided into two
classes:
 aromatic compounds, which contain benzene or
similarly aromatic rings of atoms- cyclic
 aliphatic compounds which do not contain those
rings.
Alkyl-benzenes, nomenclature:
Special names
CH3
CH3
CH3
CH3
CH3
CH3
CH3
toluene
o-xylene
m-xylene
p-xylene
others named as “alkyl benzenes”:
H3C
CH
CH3
isopropylbenzene
CH3
H2C
CH2
H2
CH3
C
CH
CH3
n-propylbenzene
isobutylbenzene
CH2 CH3
CH2 CH3
o-diethylbenzene
n-butylbenzene
Alcohols
 Alcohols are characterized by the presence of an - OH group
generally in a bent shape, like that of water.
 Due to the presence of an -OH group, alcohols can have a
hydrogen bond. This leads to higher boiling points compared
to their parent alkanes.
 Alcohols are polar in nature. This is attributed to the difference
in electronegativity between the carbon and the oxygen atoms.
 Are classified as primary, secondary, or tertiary, depending on
whether the –OH group is bonded to a primary, secondary, or
tertiary carbon
Ethers
 Ethers are a class of organic compounds that
contain an ether group — an oxygen atom
connected to two alkyl or aryl groups — of
general formula R–O–R'.
 Good solvents for organic compounds
 Unreactive because they lack the –OH unit
Aldehydes
An ALDEHYDE is an organic compound containing a formyl group.
This functional group, with the structure R-CHO, consists of
a carbonyl center (a carbon double bonded to oxygen) bonded
to hydrogen and an R group, which is any generic alkyl or side chain.
 Contain the carbonyl functional group
 Prepared by the oxidation of alcohols
Formalaldehyde
 Simplest aldehyde
 Also called by its systematic
name methanal.
 Used as :
 Disinfectant
 Fixative for human tissues
 Formaldehyde-based materials are key to the manufacture of
automobiles, and used to make components for the transmission,
electrical system, engine block, door panels, axles and brake
shoes.
Ketones
A KETONE is an organic compound with the structure RC(=O)R', where
the carbonyl group (C=O) is bonded to two other carbon atoms.
Many ketones are known and many are of great importance in industry and
in biology. Examples include many sugars (ketoses) and the industrial
solvent acetone.
Acetone
 Simplest ketone
 It is what's found in nail polish remover
and paint removers
 Urea – another example of ketone
Ketoses
 Have at least one KETONE group.
Carboxylic Acids
 Compounds that contain the carboxyl functional group are weakly
acidic because of delocalization of the  electrons, which causes
them to lose a proton and form the carboxylate anion
 Carboxylic acids are ACIDS because they are proton (H+) donors.
Carboxylic acids….
They are the most common type of organic acid.
Among the simplest examples are formic acid H-COOH, which
occurs in ants.
Another example COOH
compounds …
 acetic acid CH3-COOH, which
gives vinegar its sour taste.
 Carboxylic acids are used in the production
of polymers, pharmaceuticals, solvents,
and food additives.
Carboxylic Acid Derivatives
Esters
Esters are chemical compounds consisting of
a carbonyl adjacent to an ether linkage
Esters are usually derived from an inorganic acid or organic acid in which at
least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group, and
most commonly from carboxylic acids and alcohols.
Esters are responsible for the aroma of many fruits, including apples, durians,
pears, bananas, pineapples, and strawberries. Several billion kilograms of
polyesters are produced industrially annually.
The Molecules of Life
• All the functional groups described are found in the
organic molecules that constitute and maintain every
living organism on
• The most abundant substances found in living systems
belong to four major classes:
1. Proteins
2. Carbohydrates
3. Lipids
4. Nucleic acids
Proteins
• Proteins are biologically active polymers formed from
amino acids linked together by amide bonds; in addition
to an amine group and a carboxylic acid group, each
amino acid contains a characteristic R group
 The nature of the R group determines the particular chemical
properties of each amino acid !!!
• Some proteins are enzymes that catalyze biological
reactions
Carbohydrates
• Carbohydrates are the most abundant of the organic
compounds found in nature; they constitute a substantial
portion of food that is consumed to provide energy
needed to support life
• Carbohydrates are polyhydroxy aldehydes or
polyhydroxy ketones
– The simplest carbohydrates consist of unbranched chains of
three to eight carbon atoms; one carbon is a carbonyl carbon
and the others are bonded to hydroxyl groups
Carbohydrates
Carbohydrates
Carbohydrates are classified according to the
number of single saccharide units they contain
1. The simplest are monosaccharides
– Contain several chiral carbons and exist in several
isomeric forms
– An example is glucose
2. A disaccharide consists of two linked
monosaccharide units and an example is sucrose
3. A trisaccharide is three linked monosaccharide
units
4. Polysaccharides contain more than 10
monosaccharide units
Lipids
– Characterized by their insolubility in water
– Form a family of compounds that includes fats, waxes, vitamins
(A,D,E and K) and steroids
– Fatty acids are the simplest lipids and have a long hydrocarbon
chain that ends with a carboxylic acid functional group
1. Saturated fatty acids—the hydrocarbon chains contain only C–C
single bonds that stack in a regular array
2. Unsaturated fatty acids—have a single double bond in the
hydrocarbon chain (monounsaturated) or more than one double
bond (polyunsaturated); double bonds give fatty acid chains
a kinked structure, which prevents the molecules from
packing tightly
 The main biological functions of lipids
include storing energy, signaling, and
acting as structural components of cell
membranes
Nucleic Acids
•
Nucleic acids are the basic structural components of
DNA and RNA, the biochemical substances found in the
nuclei of cells that transmit the information needed to
direct cellular growth and reproduction !!
• Structures are derived from nitrogen-containing cyclic
compounds called pyrimidines and purines and those
are Guanine, Cytosine, Thymine and Adenine !
 • When a pyrimidine or purine is linked to a sugar by a
bond called a glycosidic bond, a nucleoside is formed; if
we add a phosphoric acid group to the sugar of
nucleoside then we get a nucleotide !
Nucleic Acids
•
Nucleotides link to form a polymeric chain (many
nucletides) that consists of alternating sugar and
phosphate groups and so create the backbone of
Deoxyribonucleic acid- DNA and Ribonucleic acid - RNA
• The function of DNA is to preserve genetic information,
and RNA translates the genetic information in DNA and
carries that information to cellular sites where proteins
are synthesized !
DNA and RNA
Readings
 Chapter 24 (second part)
 Book pages 1648 - 1673
 One more lecture to go …