Transcript Amines and Phenols

Amines
Nomenclature
 Properties
 Preparation reactions
 Characteristic reactions
 Spectroscopy

Nomenclature
and Properties
of Amines
Preparation Reactions of
Amines
Reduction reactions
 Rearrangements
 Nucleophilic substitution reactions

Amines via Reduction
 Reduction
of nitro compounds
 Reduction of nitriles
 Reduction of amides
 Reduction of imines/enamines
 Reductive amination of
aldehydes/ketones
Amines via Reduction: A Summary
R NO 2
R CN
H2 / Pt or LiAlH4
H 2 / Pt or LiAlH4
R C NH 2
O
LiAlH 4
O
R C NR' 2
LiAlH 4
O
NH
R''
R' C
NR
R''
C
CH
H2 / Pt
or
LiAlH 4
H2 / Pt
or
LiAlH 4
NR 2
RCH 2 NH 2
LiAlH 4
R C NHR'
R' C
R NH 2
+
or Sn / H
H
R'
C NH 2
R''
H
R'
C NHR
R''
H 2 / Pt or LiAlH4
RCH 2 NH 2
RCH 2 NHR'
RCH 2 NR' 2
NH 3
R' C
H 2 / Pt
R''
RNH 2
H2 / Pt
C
H
O
R' C
O
R''
CH 2 NR 2
Amines via Rearrangement


Hofmann rearrangement (degradation)
Curtius rearrangement
R
C NH 2
O
X2
-
OH /H2O
²
RNH 2 + CO 2
Primary amide
+
R C N N N
O
Acyl azide
²
H 2O
RNH 2 + CO 2
+ N2
Amines via Bimolecular
Nucleophilic Substitution
O
O
O
C
C
C
N H
Gabriel
Synthesis
KOH
N K
RCH2 X
N CH2 R
C
C
C
O
O
O
O
O
C
C O
-
N CH2 R
OH /H2 O

RCH2 NH 2 +
C
C O
O
O
RCH2 X + NH 3
RCH2 NH 2
Alkylation
+
RCH2 NHCH2 R
RCH2 X
RCH2 NHCH2 R
(RC H2 )3 N
RCH2 NH 2
RCH2 X
RCH2 X
(RC H2 )3 N
(RC H2 )4 N
+
X
Amine Reactions
Reaction
as Bases: Salt Formation
Amide Formation
Alkylation
Reaction with Nitrous Acid
Amine Reactions with Nitrous Acid



Primary amines: Diazotization
Secondary Amines: Nitrosamine formation
Tertiary Amines: C-nitroso compounds
RNH 2
HONO
o
0 C
ArNH 2
HONO
o
0 C
R 2NH
or
ArNHR
+
R N N
alkyl diazonium salt
unstable
+
Ar N N
Nu
+ R
N2
+ Ar Nu
aryl diazonium salt
stable at low temp.
HONO
o
0 C
R
N
N
Ar
R
or
N
N
O
R
O
Nitrosamines
NR 2
HONO
o
0 C
O
N
+
N2
NR 2
Aromatic C-nitroso compound
Mechanism of Diazonium salt formation
H O N
H
H
R
+
O N
O + H
O
NH 2 +
+
N
R
N
O
H
O
+
N N
N N
N N
N N
+
R
N N
O
H
N-nitrosoamm onium
ion
O
+
H2 O
R
N N
+
O + H3 O
H
N-nitrosam ine
O
R
t aut omerizat ion
H
R
+
+
O
nit rosonium
ion
H
R
O N
H
H2 O
H
R
+
H
+
O
H
H
R
R
OH
a diazenol
+
OH + H
+
N N
+
N N
N N
+
a diazonium
ion
+
O
H
H
H2 O
Diazonium Salt Reactions
HO
N N
an azo dye
I
KI
OH
H2 O
Phenol
+
heat
CN
N N
Cl
CuCN
CuCl
CuBr
H3 PO2
1. HBF4
2. heat
Br
H
F
Reactions of Phenols
 Salt
formation via strong base or active metal
 Williamson ether synthesis
 Ester formation
 Friedel-Crafts acylation: Fries rearrangement
 Halogenation
 Coupling with diazonium salts
 Kolbe-Schmitt Carboxylation
 Reimer-Tiemann reaction
Phenol Reactions: A Summary
OR
-
O Na
1. NaOH
+
2. RX (primary)
NaOH
CO2
OH
or
Na
AlCl3
(RC O)2 O
OH
-
C O Na
O
+
ArN 2
CHCl3
OH
+
R
NaOH
OH
O- Na +
C
O
H
N
N
Ar
C
O
RCOCl
or
4-7 atm
heat
O
C
O
R
Halogenation of Phenols
OH
OH
OH
Cl2
Br2
no solvent
high tem p.
CS2
low temp.
Cl
Br
No Lewis acid is required
major
product
OH
OH
Cl
Cl
Cl
major
product
OH
Cl2
Br2
H2 O
H2 O
No Lewis acid is required
Br
Br
Br
Reimer-Tiemann Reaction Mechanism
O
C
CHCl3
Overall:
OH
NaOH/H2 O
heat
H
salicylaldehyde
OH
CHCl3 + OH-
CCl3 - + H2 O
CCl3 -
CCl2 + Cla carbene
O
OH
O
+ OH-
H
-
O
O
O
CCl2
H +
CHCl2
H
CCl2
O-
OH
CHCl2
H2 O
heat
O
C
H
+
2 HCl