DRAWING ORGANIC STRUCTURES
FUNCTIONAL GROUPS
CONSTITUTIONAL ISOMERS
Dr. Clower
CHEM 2411
Spring 2014
McMurry (8th ed.) sections 1.12, 3.1, 3.2
Draw these structures…
• C2H6
• CH4O
• C3H6 (contains C=C)
• C4H10 (multiple possible answers)
More Lewis structures…
• CH5N
• CHN
• HNO3
• Remember…
• Keep in mind total available valence electrons
• Try to minimize formal charges
• Patterns for formal charge
Drawing Organic Structures
• Example: isopropyl alcohol (C3H80)
• Lewis structure
• Show all bonds, atoms, lone pairs
• Condensed structure
• Omit some bonds (C─C, C─H, O─H, N─H)
• Often omit lone pairs
• Skeletal structure/line-angle drawing
• Show bond framework as lines
• C atoms at intersections of lines (bonds) and end of each line
• H atoms bonded to C are not shown
• Heteroatoms (atoms other than C and H) are shown
Drawing line-angle structures
Name
Acetone
Butane
1-Butene
Cyclohexane
Benzene
Lewis structure
Condensed structure
Line-angle drawing
Interpreting line-angle structures
• What is the molecular formula for adrenaline?
• What is the molecular formula for thalidomide?
Drawing Organic Structures
• Draw Lewis and line-angle structures for this condensed
structure: (CH3)3CCH2COCHCH2
Functional Groups
• Collection of atoms at a
site within a molecule
with a common bonding
pattern
• Reacts in a typical way,
generally independent of
the rest of the molecule
• Four broad classes
• Hydrocarbons
• Compounds containing O
• Compounds containing N
• Compounds containing S
or P
1. Hydrocarbons
• Alkane: single bonds, sp3 carbons
• Cycloalkane: carbons form a ring
• Alkene: double bond, sp2 carbons
• Cycloalkene: double bond in ring
• Alkyne: triple bond, sp carbons
• Aromatic (arene): contains a benzene ring
• Not a hydrocarbon, but related…
• Alkyl halide: R─X
• R = any carbon group
• X = halogen
2. Compounds containing oxygen
• Alcohol: R─OH
• Ether: R─O─R'
• Carbonyl group: C=O
O
• Aldehyde: RCHO
CH3CH2
• Ketone: RCOR'
C H
O
CH3
C CH3
Carboxylic acids and their derivatives
• Carboxylic Acid: RCOOH
O
C OH
O
• Acid Chloride: RCOCl
C Cl
O
• Ester: RCOOR' (RCO2R’)
C OCH
3
O
• Amide: RCONH2
• Acid Anhydride: RCO2COR
C NH
2
3. Compounds containing nitrogen
• Amines: RNH2, RNHR', or R3N
• Amides: RCONH2, RCONHR, RCONR2
• Nitrile: RCN
CH3
C N
4. Compounds containing S or P
• Phosphates (PO42-)
• Thiol (R─SH)
• Sulfides (R─S─R)
• Sulfoxides (S=O)
• Thioester (RCOSR)
Isomers
• Isomers have the same molecular formula, but different
arrangements of atoms
• Constitutional isomers
• differ in their connectivity
• Stereoisomers
• differ in the spatial arrangement/orientation of their atoms
Constitutional Isomers
• Molecules with the same molecular formula, but different
connectivity
• Same number and kinds of atoms
• Differ in which atoms are bonded
• Example: C4H10
• Straight-chain (“normal”) alkane vs. branched-chain alkane
Constitutional Isomers
Constitutional Isomers
• Are the following pairs of molecules constitutional
isomers, the same molecule, or neither?
(a)
(b)
(c)
(d)