chemistry 2100 lecture 3. discovering aromatics c6h6c6h6 1.54 Å 1.33 Å 1.39 Å
TRANSCRIPT
Chemistry 2100
Lecture 3
Discovering Aromatics
C6H6 Ladenburg 1878
Dewar 1867CH3C C C C CH3
CHH2C C C CH CH2 Br 2 / Fe
(- HBr )C6H6 C6H5Br
Br 2 / Fe
(- HBr )C6H4Br2
1.54 Å 1.33 Å 1.39 Å
CH3 CH3 CH2 CH2 C6H6
Aromatics H H
H
H
H
H H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H H
H H
H H
Resonance
H H
H H
H H
Resonance
H H
H H
H H
Resonance
H H
H H
H H
Resonance
H H
H H
H H
Resonance
H H
H H
H H
Resonance
H H
H H
H H
Resonance
H H
H H
H H
Resonance
Resonance
Graphene
Carbon Nanotubes
Nomenclature for Arenes
• Many common names retained• Blah• PAH
PhenanthreneAnthraceneNaphthalene Benzo[a]pyrene
Aromatic Reactions
Noteworthy Phenols hexachlorophene
OHCl
Cl Cl
CH2
Cl
ClCl
HO eugenol
HO
CH3O hexylresorcinol
OH
HO OH
Cl
O
CH3HO
OHOH
HN(CH3)2
OH
O
CONH2
aureomycin
O
HO
tetrahydrocannabinol
Phenol Acidity
>>
acids > thiols ~ phenols > water ~ alcohols
C OHCH3
O
OH CH3 OH
Acidity:
acids > phenols ~ thiols > water ~ alcohols
Ka % ionized [H3O+], M pH
~1 107 ~100 ~0.1 1.00
1.8 10–5 1.3 1.3 10–3 2.88
3.3 10–10 0.0036 3.6 10–6 5.44
2.5 10–11 0.0016 1.6 10–6 5.80
1.3 10–16 0.0001 1.0 10–7 7.00
HCl
HOAc
PhOH
EtSH
EtOH
HOH
Comparative acidities of 0.1 M aqueous solutions of representative acids HA
1.8 10–16 0.0001 1.0 10–7 7.00
Phenols as AntioxidantsAutoxidation
CH2CH=CH-CHH
CH2CH=CH-CHSection of a fatty
acid hydrocarbon chainA carbon radical
lightor heat
CH2CH=CH-CH-CH2
O-O-H
A hydroperoxide
CH2CH=CH-CHO-O
CH2CH=CH-CH
H+
+ CH2CH=CH-CH A new carbon radical
Section of a new fattyacid hydrocarbon chain
CH2CH=CH-CH O-O CH2CH=CH-CHO-O
A hydroperoxy radical
+Oxygen is adiradical
Natural Phenolic Antioxidants
HO
O
CH3
CH3CH3CH3
CH3
CH3CH3 CH3
Vitamin E ( tocopherol)Vitamin E tocopherol) OH
OH
HO
Resveratrol
Man-made Phenolic Antioxidants
OH
CH3
BHT
OH
OCH3
BHA
methyl paraben
OC
OCH3
OH
Phenols as… Weapons?
CH2 CH NH2
COOH
phenylalanine
CH2 CH NH2
COOH
phenylalanine
[O]
tyrosine
CH2 CH NH2
COOH
HO
CH2 CH NH2
COOH
phenylalanine
[O]
L-DOPA
CH2 CH NH2
COOH
HO
HO
[O]
tyrosine
CH2 CH NH2
COOH
HO
CH2 CH NH2
COOH
phenylalanine
[O]
L-DOPA
CH2 CH NH2
COOH
HO
HO
[O]
tyrosine
CH2 CH NH2
COOH
HO
CH2 CH NH2
COOH
phenylalanine
[O]
L-DOPA
CH2 CH NH2
COOH
HO
HO
[O]
tyrosine
CH2 CH NH2
COOH
HO
CH2 CH NH2
COOH
phenylalanine -CO 2
CH2 CH2 NH2
HO
HO
dopamine
[O]
L-DOPA
CH2 CH NH2
COOH
HO
HO norepinephrine
CH CH2 NH2
HO
HO
OH
[O]
[O]
tyrosine
CH2 CH NH2
COOH
HO
CH2 CH NH2
COOH
phenylalanine -CO 2
CH2 CH2 NH2
HO
HO
dopamine
epinephrine
"CH 3"CH CH2 NH
HO
HO
OH
CH3
[O]
L-DOPA
CH2 CH NH2
COOH
HO
HO norepinephrine
CH CH2 NH2
HO
HO
OH
[O]
[O]
tyrosine
CH2 CH NH2
COOH
HO
CH2 CH NH2
COOH
phenylalanine -CO 2
CH2 CH2 NH2
HO
HO
dopamine
epinephrine
"CH 3"CH CH2 NH
HO
HO
OH
CH3
[O]
L-DOPA
CH2 CH NH2
COOH
HO
HO norepinephrine
CH CH2 NH2
HO
HO
OH
[O]
[O]
tyrosine
CH2 CH NH2
COOH
HO
CH2 CH NH2
COOH
phenylalanine -CO 2
CH2 CH2 NH2
HO
HO
dopamine
CH CH NH
"phenethylamine"
CH CH NH
ephedrine (ephedra) / pseudoephedrine
OH
CH3 CH3
ephedrine (ephedra) / pseudoephedrine
OH
CH3
CH CH NH
CH3
CH CH NH 2
CH3
methylenedioxymethamphetamine / MDMA / Ecstacy
CH3
CH CH NH 2
O
O
CH3
methylenedioxymethamphetamine / MDMA / Ecstacy
CH3
CH CH NH 2
O
O
CH3
methylenedioxymethamphetamine / MDMA / Ecstacy
CH3
CH CH NH 2
O
O
CH3
methylenedioxymethamphetamine / MDMA / Ecstacy
CH3
Organic Food Dye: Carminic Acid
carminic acid
O
O
OH
COOH
OH
OH
HO
HO
OH
Aromatic Heterocycles
nicotineniacin (B3) / nicotinamide
thiamine (B1)
N
NCH3
N
C NH2
O CH3
NH2
CH3
N
N
CH2
N
S
CH2CH2OHCl
caffeine(theobromine)
CH3
N
N
CH3
N
N(H) CH3
O
O• •
••
Heterocycles store life’s information
(U) T = A
N
N
O
O
H
(H) CH3
Sugar
(U) T = A
Sugar
H
H N N
NN
N
N
N
O
O
H
(H) CH3
Sugar
(U) T = A
Sugar
H
H N N
NN
N
N
N
O
O
H
(H) CH3
Sugar
(U) T = A
Sugar
H
H N N
NN
N
N
N
O
O
H
(H) CH3
Sugar
(U) T = A
Sugar
H
H N N
NN
N
N
N
O
O
H
(H) CH3
Sugar
(U) T = A
Sugar
H
H N N
NN
N
N
N
O
O
H
(H) CH3
Sugar
(U) T = A
Sugar
H
H N N
NN
N
N
N
O
O
H
(H) CH3
Sugar
1.085 nm
(U) T = A
Sugar
H
H N N
NN
N
N
N
O
O
H
(H) CH3
Sugar
1.085 nm
(U) C = G
H
Sugar
H
H
O
N
N
N
N
N
N
N
N
OSugar
H
H