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Solutions for Ketones and Aldehydes
steps in imine formation are equilibria.
O
N
NH3
H2O
H2O
NH2
O H
N
H
H
N
H
HC
O
NH2
H H
(a)
− H2O
O
H C
O
H
H
NH2
O H
H3O+
H
A
B
C
DE
F
Imine formation has six steps: four are proton transfers, one is 
a nucleophilic attack, and one is a leaving group leaving.
A
B
C
D
E
F
proton on (resonance-stabilized cation)
nucleophile attacks
proton off
proton on
leaving group leaves (resonance-stabilized cation)
proton off
O
N
NH2Ph
H2O
H2O
NHPh
O H
N
H
Ph
N
Ph
HC
O
NHPh
H H
(b)
− H2O
O
H C
O
H
H
NHPh
O H
H3O+
Ph
A
B
C
DE
F
H A
H A
21 Imine formation has optimum pH 4-5 where protonation of the carbonyl oxygen is the first step. All 
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