Upload
jared-shelton
View
253
Download
9
Embed Size (px)
Citation preview
Chapter 22Chapter 22Organic and Biological Organic and Biological
ChemistryChemistry
Organic ChemistryOrganic Chemistry• The chemistry of carbon
compounds.• Carbon has the ability to form
long chains.• Without this property, large
biomolecules such as proteins, lipids, carbohydrates, and nucleic acids could not form.
HydrocarbonsHydrocarbons• Four basic types:
o Alkaneso Alkeneso Alkyneso Aromatic
hydrocarbons
AlkanesAlkanes
• Only single bonds.• Saturated hydrocarbons.
o “Saturated” with hydrogens.
FormulasFormulas• Lewis structures of alkanes look like
this.• Also called structural formulas.• Often not convenient, though…
FormulasFormulas…so more often condensed formulas are
used.
Properties of AlkanesProperties of Alkanes
• Only van der Waals force: London force.• Boiling point increases with length of chain.
IsomersIsomers
Have same molecular formulas, but atoms are bonded in different order.
Organic NomenclatureOrganic Nomenclature• Three parts to a compound name:
o Base: Tells how many carbons are in the longest continuous chain.
Organic NomenclatureOrganic Nomenclature• Three parts to a compound name:
o Base: Tells how many carbons are in the longest continuous chain.
o Suffix: Tells what type of compound it is.
Organic NomenclatureOrganic Nomenclature• Three parts to a compound name:
o Base: Tells how many carbons are in the longest continuous chain.
o Suffix: Tells what type of compound it is.o Prefix: Tells what groups are attached to
chain.
Bases(Parent)Bases(Parent)
BranchesBranches
To Name a Compound…To Name a Compound…1. Find the longest chain
in the molecule(base).
2. Number the chain from the end nearest the first substituent(branch) encountered.
3. List the branches as a prefix along with the number(s) of the carbon(s) to which they are attached.
To Name a Compound…To Name a Compound…4.If there is more
than one type of branch in the molecule, list them alphabetically. Use prefixes,di-, tri-, to indicate multiple branches.
Example 1: Example 1: 2,2-2,2-dimethylpentanedimethylpentane
• The parent chain is indicated by the ROOT of the name - “pentanepentane”. This means there are 5 carbons in the parent chain.
CH3
CH2CH2
CH2CH3
• “dimethyldimethyl” tells us that there are TWO methyl branches on the parent chain. A methyl branch is made of a single carbon atom.
• “2,22,2-” tell us that BOTH methyl branches are on the second carbon atom in the parent chain.
CH31
CCH23
CH24
CH35
CH3
CH3
1
2
3
4
5
Example 2: Example 2: 3-ethyl-2,4-3-ethyl-2,4-
dimethylheptanedimethylheptane• The parent chain is
indicated by the ROOT of the name - “heptaneheptane”. This means there are 7 carbons in the parent chain.
CH3
CH2CH2
CH2CH2
CH2CH3
• “2,4-dimethyl2,4-dimethyl” tells us there are TWO methyl branches on the parent chain, at carbons #2 and #4.
• “3-ethyl3-ethyl-” tell us there is an ethyl branch (2-carbon branch) on carbon #3 of the parent chain.
1
2
3
4
5
76
CH3
CHCH
CHCH2
CH2CH3
CH2CH3
CH3 CH3
Example 3: Example 3: 2,3,3-trimethyl-4-2,3,3-trimethyl-4-
propyloctanepropyloctane• The parent chain is
indicated by the ROOT of the name - “octaneoctane”. This means there are 8 carbons in the parent chain.
• “2,3,3-trimethyl2,3,3-trimethyl” tells us there are THREE methyl branches - one on carbon #2 and two on carbon #3.
• “4-propyl4-propyl-” tell us there is a propyl branch (3-carbon branch) on carbon #4 of the parent chain.
1
2
34
5
7
6
8
1
23
45
7
6
8
CHC
CHCH2
CH2
CH2CH3
CH3
CH3
CH3
CH3CH2
CH2
CH3
Example 4: Name the Example 4: Name the
molecules shown!molecules shown!• parent chain has 5 carbons
- “pentane”• two methyl branches -
start counting from the right - #2 and #3
• 2,3-dimethylpentane2,3-dimethylpentane
CH3
CH2CH
CHCH3
CH3
CH3
• parent chain has 8 carbons - “octane”
• two methyl branches - start counting from the left - #3 and #4
• one ethyl branch - #5• name branches alphabetically
3,4-dimethyl3,4-dimethyl
4433
octaneoctane
55
5-ethyl-5-ethyl-
CycloalkanesCycloalkanes• Carbon can also form ringed structures.• Five- and six-membered rings are most
stable.o Can take on conformation in which angles are
very close to tetrahedral angle.o Smaller rings are quite strained.
AlkenesAlkenes
• Contain at least one carbon–carbon double bond.
• Unsaturated.o Have fewer than maximum number of
hydrogens.
Structure of AlkenesStructure of AlkenesThis creates geometric isomers, which differ from each other in the spatial arrangement of groups about the double bond.
Nomenclature of AlkenesNomenclature of Alkenes• Chain numbered so double bond gets smallest
possible number.• cis- alkenes have carbons in chain on same
side of molecule.• trans- alkenes have carbons in chain on
opposite side of molecule.
AlkynesAlkynes
• Contain at least one carbon–carbon triple bond.
• Carbons in triple bond sp-hybridized and have linear geometry.
• Also unsaturated.
Nomenclature of AlkynesNomenclature of Alkynes
• Analogous to naming of alkenes.• Suffix is -yne rather than –ene.
4-methyl-2-pentyne
Aromatic HydrocarbonsAromatic Hydrocarbons
• Cyclic hydrocarbons.• Molecule is planar.• Many aromatic
hydrocarbons are known by their common names.
Structure of Aromatic Structure of Aromatic CompoundsCompounds
• Two substituents on a benzene ring could have three possible relationshipso ortho-: On adjacent carbons.o meta-: One carbon between them.o para-: On opposite sides of ring.
Functional Functional GroupsGroups
Term used to refer to parts of organic molecules where reactions tend to occur.
AlcoholsAlcohols• Contain one or more hydroxyl groups, —OH
• Named from parent hydrocarbon; suffix changed to -ol and number designates carbon to which hydroxyl is attached.
EthersEthers
• Tend to be quite unreactive.• Therefore, they are good polar
solvents.
Carbonyl CompoundsCarbonyl Compounds• Contain C—O
double bond.• Include many
classes of compounds.
AldehydesAldehydesAt least one hydrogen attached to carbonyl carbon.
KetonesKetonesTwo carbons bonded to carbonyl carbon.
Carboxylic AcidsCarboxylic Acids• Have hydroxyl
group bonded to carbonyl group.
• Tart tasting.• Carboxylic acids
are weak acids.• Naming:
_____oic acid
CH3COOH
Carboxylic AcidsCarboxylic Acids
EstersEsters• Products of
reaction between carboxylic acids and alcohols.
• Found in many fruits and perfumes.
butanoate
AminesAmines• Organic bases.• Generally have strong, unpleasant
odors.
AmidesAmidesFormed by reaction of carboxylic acids with amines.This is the reaction that occurs between amino acids