Organic Chemistry

1
Organic Chemistry

• Introduction
• Functional Groups
• Names and Structures
• Alkanes
• Cycloalkanes
• Alkenes
• Alkynes
• Alcohols

2
Introduction

• Organic chemistry is the study of
  carbon-containing compounds
• The field of organic chemistry is very important
  for a wide variety of reasons.
• A huge number of carbon-containing compounds are
  known.
• Most of the advances in the pharmaceutical
  industry are based on a knowledge of organic
  chemistry.
• Life as we know it is based on organic chemistry.

3
Introduction

• Most organic compounds have a skeleton that is
  composed of C-C bonds.
• The C-C bonds may be single bonds, double bonds,
  or triple bonds.
• Carbon forms a total of 4 bonds.
• The skeleton of an organic compound has Hs
  attached to it.
• other heteroatoms like O, halogens, N, S, and P
  may be present as well

4
Introduction

• Some familiar organic compounds

propane
methane
acetylene
acetone
5
Introduction

• Some familiar organic compounds

Acetic acid
ether
aspirin
Ethyl alcohol
6
Introduction

• Organic compounds are commonly classified and
  named based on the type of functional group
  present.
• An atom or group of atoms that influences the way
  the molecule reacts, behaves, or functions
• The center of reactivity in an organic compound

7
Functional Groups

• On your exam, you will be responsible for
  recognizing and naming the various common
  functional groups that are found in organic
  compounds
• Use Table 25.4 and the following slides to help
  you study

8
Functional Groups
Class of Compound Functional Group
Alkane None
Cycloalkane None
Alkyl halide
Alkene
Alkyne
Alcohol
Ether
9
Functional Groups
Class of Compound Functional Group
Aldehyde
Ketone
Carboxylic Acid
Ester
10
Functional Groups
Class of Compound Functional Group
Amine
Amide
Nitrile
Aromatic ring
11
Alkanes

• Contain C-C single bonds
• no functional group
• Tetrahedral electron domain geometry
• sp3 hybridized carbons
• Free rotation around single bonds

propane
12
Cycloalkanes

• Contain C C with at least 3 of the carbons
  arranged in a cyclic (ring) structure
• No functional group
• Tetrahedral ed geometry
• sp3 hybrid orbitals

13
Alkyl Halides

• Contain C-halogen bond
• F, Cl, Br, or I
• Alkyl halides are generally (but not always)
  polar molecules.

14
Alkenes

• Contain CC (carbon-carbon double bonds)
• 1 sigma bond 1 pi bond
• Trigonal planar geometry
• sp2 hybridized carbons

Which atoms must be coplanar in an alkene?
1-propene
15
Alkenes

• The CC present in an alkene is composed of 1
  sigma (s) bond and 1 pi (p) bond.
• Double bonds are rigid and cannot rotate freely.
• Rotation would cause loss of overlap of the p
  orbitals, destroying the p bond.

ethylene
16
Alkynes

• Contain C C (carbon-carbon triple bonds)
• 1 sigma bond
• 2 pi bonds
• Linear electron domain geometry
• sp hybridized carbons

Which atoms must be co-linear in an alkyne?
17
Aromatic Ring

• Planar ring system with alternating single and
  double bonds
• does not react like an alkene
• Trigonal planar
• sp2 hybridized carbons
• Benzene ring is a very common aromatic ring.

benzene
pyridine
18
Functional Groups

• Alkanes are often called saturated hydrocarbons
• Organic compounds composed of carbon and hydrogen
  that contain the largest possible number of
  hydrogen atoms per carbon atom.
• Alkenes, alkynes, and aromatic hydrocarbons are
  called unsaturated hydrocarbons
• Organic compounds composed of carbon and hydrogen
  that contain less hydrogen than an alkane having
  the same number of carbon atoms

19
Alcohols

• Contain C-O-H bond
• hydroxyl group
• Alcohols form hydrogen bonds between molecules.
• How does hydrogen bonding affect boiling point???
• Amphoteric

20
Ethers

• Contain C-O-C bond
• tetrahedral e.d. geometry
• why?
• bent molecular geo.
• why?

21
Amines

• Contain C-N-R
• R
• R and R can be H or C
• Primary and secondary amines form hydrogen bonds.
• Common organic bases
• lone pair of e- on N

22
Aldehydes

• Contain (-CHO)
• Carbonyl (CO)
• always on the 1st or last carbon in a chain
• trigonal planar geometry
• sp2 hybrid orbitals

23
Ketones

• Contain
• Carbonyl attached to middle of chain
• Trigonal planar e.d. geo.
• sp2 hybridized C

24
Carboxylic Acids

• Contain carboxyl group
• Form hydrogen bonds
• trigonal planar
• sp2 hybridized carbon

25
Esters

• Contain
• trigonal planar
• sp2 hybridized

26
Amides

• Contain
• where R and R H or C
• CO is trigonal planar sp2 hybridized

27
Nitriles

• Contain
• Linear
• sp hybridized C

28
Functional Groups

• Example Identify the functional groups present
  in the following compounds.

thyroxine
testosterone
29
Functional Groups

• Example Identify the functional groups in the
  following compounds.

Lisinopril
Vanillin
30
Depicting Structures of Organic Compounds

• Organic compounds can be depicted using a variety
  of formulas
• Empirical formula
• Molecular formula
• Lewis structure
• Full structural formula
• Three dimensional drawings
• Condensed structural formula
• Line angle drawings

31
Depicting Structures of Organic Compounds

• Ethyl acetate is an organic molecule with
• empirical formula C2H4O
• molecular formula C4H8O2

32
Depicting Structures of Organic Compounds

• Ethyl acetate is an organic molecule with
• Lewis structure
• depicts all covalent bonds using a straight line
  and shows all nonbonding pairs of electrons
• Full structural formula
• a Lewis structure without the nonbonding electrons

33
Depicting Structures of Organic Compounds

• Ethyl acetate is an organic molecule with
• 3-d drawing
• Condensed structural formula
• Line angle drawing

34
Names and Structures of Alkanes

• Some of the simplest alkanes

You must know these!!!
35
Names and Structures of Alkanes

• Some of the simplest alkanes

You must know these!!!
36
Names and Structures of Alkanes

• The previous alkanes are also called
  straight-chain hydrocarbons
• all of the carbon atoms are joined in a
  continuous chain
• Alkanes containing 4 or more carbons can also
  form branched-chain hydrocarbons (branched
  hydrocarbons)
• some of the carbon atoms form a branch or
  side-chain off of the main chain

37
Names and Structures of Alkanes

• An example of a straight chain hydrocarbon
• C5H12 CH3CH2CH2CH2CH3 pentane
• Examples of a branched hydrocarbon
• C5H12 CH3CHCH2CH3 CH3
• CH3 CH3CCH3
• CH3

2-methylbutane
2,2-dimethylpropane
38
Names and Structures of Alkanes

• The three structures shown previously for C5H12
  are structural isomers
• compounds with the same molecular formula but
  different bonding arrangements
• Structural isomers are unique compounds and
  generally have different properties
• different melting points
• different boiling points
• often different chemical reactivity

39
Names and Structures of Alkanes

• Organic compounds can be named either using
  common names or IUPAC names.
• You must be able to name alkanes, cycloalkanes,
  alkyl halides, alkenes, alkynes, and alcohols
  with 10 or fewer carbons in the main chain (or
  ring) using the IUPAC naming system.

40
Names and Structures of Alkanes

• Alkane Nomenclature
• Find the longest continuous chain of carbon atoms
  and use the name of the alkane with the same
  number of carbons for the base name of the
  compound
• The longest chain is not always written in a
  straight line.

Base name heptane
41
Names and Structures of Alkanes

• Number the carbon atoms in the longest chain
  beginning with the end of the chain closest to a
  substituent
• groups attached to the main chain that have taken
  the place of a hydrogen atom on the main chain

A substituent
42
Names and Structures of Alkanes

• Name and give the location of each substituent
• Common substituents
• Halo group
• a halogen atom
• Halo groups are named using halo
• Cl chloro
• Br bromo
• I iodo
• F fluoro

43
Names and Structures of Alkanes

• Common substituents
• alkyl group
• A substituent that is formed by removing an H
  atom from an alkane
• the alkyl group attaches to the main chain at the
  carbon that has lost its H

44
Names and Structures of Alkanes

• Alkyl groups are named by replacing the ane
  ending of the parent alkane with the yl ending.
• Alkyl groups to know

45
Names and Structures of Alkanes

• Alkyl groups to know (cont)

46
Names and Structures of Alkanes
Methyl group
3-methylheptane
Note Separate numbers from letters using a
hyphen. Separate groups of numbers using commas.
47
Names and Structures of Alkanes

• Alkane Nomenclature
• When two or more substituents are present, list
  them in alphabetical order
• Butyl vs. ethyl vs. methyl vs. propyl
• When more than one of the same substituent is
  present (i.e. two methyl groups), use prefixes to
  indicate the number. Give the location of each
  as well.
• Di two
• Tri three
• Tetra four
• Penta five

Note Ignore these prefixes when alphabetizing.
48
Names and Structures of Alkanes

• Additional rules
• If each end of the longest chain has a
  substituent the same distance from the end, start
  with the end nearer to the second substituent.

correct
incorrect
3-chloro-2,5-dimethylhexane
49
Names and Structures of Alkanes

• Example Name the following compounds

50
Names and Structures of Alkanes

• You must also be able to draw the structure of an
  alkane when given the IUPAC name.
• Identify the main chain and draw the carbons in
  it
• Identify the substituents (type and ) and attach
  them to the appropriate carbon atoms on the main
  chain.
• Be sure to connect the proper atoms when drawing
  bonds.
• Add hydrogen atoms to the carbons to make a total
  of 4 bonds to each carbon

51
Names and Structures of Alkanes

• Example Draw the condensed structure for the
  following compounds. Draw a line angle drawing
  for each.
• 2,2-dimethylbutane
• 2-bromo-3-ethylhexane

52
Names and Structures of Alkanes

• Example Draw the condensed structure for the
  following compound. Draw a line angle drawing
  for it.
• 2-methyl-4-propyloctane

53
Names and Structures of Cycloalkanes

• Cycloalkanes are named by
• Use cyclo as a prefix with the name of the alkane
  with the same number of carbons present in the
  ring as the base name.
• Identify the substituents present using name and
  position number
• No position number is used if only one
  substituent is present.
• For 2 or more substituents, number the ring to
  give the lowest possible numbers for the
  substituted carbons.

54
Names and Structures of Cycloalkanes
isopropylcyclohexane
1,1-dibromo-3-methylcyclopentane
55
Names and Structures of Cycloalkanes

• Example Name the following compounds.

56
Names and Structures of Cycloalkanes

• Example Draw the following compounds.
• 1-chloro-3-ethylcyclohexane
• bromocyclobutane