Nitration of Methyl Benzoate

COOCH3

HNO3, H2SO4

COOCH3

NO2

COOCH3COOHCH3OH

H2SO4

Multistep Synthesis

A B C50% 50%

Yield =

25%

(CH3)3COH (CH3)3ClHCl

Nucleophilic Aliphatic Substitution

NO2+

+

H NO2

Electrophilic Aromatic Substitution

ARENE SUBSTITUTION

EE+

+ H+

The electrophile REPLACES H+

H E - Y

H E

+

H E

+

H E

+

E

+ H+

Charge o and p

Nitration of BenzeneNO2

HNO3

H2SO4

Nitrobenzene

Nitration Reagent

Nitronium Ion

HONO2 + 2 H2SO4 NO2+ + H3O+ + 2 HSO4

-

HNO2

+ H NO2

+

NO2

+ H+

Multiple SubstituentsG

G G

G

Second Group. Where go? How fast?

Nitration of TolueneCH3

CH3

NO2

CH3

NO2

CH3

NO2

HNO3

63% 3% 34%

CH3NO2

H

CH3NO2

H+

+ +

CH3

NO2

H

CH3

NO2

H

CH3

NO2

H

CH3

NO2H

CH3

NO2H

+

+

+

+ ++

ORTHO

META

PARA

G

Electron donating groups favor reaction ORTHO and PARA.

Electron Donating

Ortho

Para

CF3

Nitration of (trifluoromethyl)benzene

HNO3

H2SO4

CF3

NO2

CF3

NO2

CF3

NO2

6% 91% 3%

CF3

Electron Withdrawing group

+ charge here bad

CF3H

NO2

CF3H

NO2

CF3H

NO2

CF3

H

NO2

CF3

H

NO2

Ortho

Meta

Para

++ +

+

+

+

+ ++

Z

Electron Withdrawing Groups are Meta Directors and DEACTIVATING

ElectronWithdrawing Group

Meta Product

COOCH3

HNO3, H2SO4

COOCH3

NO2

Main Reaction

meta

Procedure

1. Dissolve methyl benzoate in H2SO4

2. Mix HNO3 and H2SO4 at 0oC

3. Add HNO3 / H2SO4

dropwise to methyl benzoate at 0oC

4. Let stand at roomtemperature 10 minutes

5. Pour onto ice

Filter

Wash

Recrystallize frommethanol

Dry

Weigh

m.p.