Friedel Craft Reaction-4.Ppt (1)

7/26/2019 Friedel Craft Reaction-4.Ppt (1)

1/14

1

Friedel-CraftRaction

1

Dr. M. Abbas BhattiPh.D (Scholar-BZU), M.Phil (PU),B.Phar (PU)

Pharmaceutical Chemistry

Islam College of Pharmacy, Sialkot.


2/14

2

S!bstit!tion

"lectro#hilic S!bstit!tion reaction(aroatic s$ste)%

The reaction in which

hydrogenof Benzene aromatic system! isre"laced#y an electro"hile"ositi$ely charged

electron lo$ing grou"! are calledelectro"hilic

su#ustitution reaction.

%%& "age


3/14

'

&earnin' obecties

(hat is )riedel*craft reaction and its "rinci"les

+efinition of ewis acid-

Ty"e of )riedel*craft reactions- Significance and "harmaceutial a""lications of

)riedel*craft reactions.


4/14

&

Friedel-Crafts Reaction

n alkyl grou"can #e introducedinto an

aromatic ring#y a reaction known as )riedel*

Crafts reaction.

In this reaction an aromatic com"oundis

treated with an alkyl or acylhalides in the

"resence of a ewis acidlCl', )eCl'/other

metal halides! 0 su#stitutedaromaticcom"ound is formed.


5/14

lCl'

These are further di$idedinto

I. )riedel*Crafts lkylation. II. )riedel*Crafts cylation.

*. Friedel-Crafts Al+$lation%

The reaction of an alkyl halidewith#enzenein

the "resence of ewis acid catalyst lCl'! is

called 3

4 C5'Cl 4 5CllCl'

C5'

Benzene Toluene


6/14

%

Mechanis. )ollowing ste"s are in$ol$ed

Ste# .)ormation of the electro"hile C5'!.

C5'6 Cl 4 lCl' C5' 4 lCl&

Ste# .The electro"hile attacks the #enzenering to gi$e a car#onium ion.

4 C5'

/

5

C5'

Benzene Car#onium ion


7/14

7

5

Ste# 0.oss of "roton gi$es alkyl#enzene.

4 5Cl 4 lCl'

5

C5'

C5'

lCl&

4

8

Toluene


8/14

9

A##lications%

)riedel*Crafts alkylation is the most usefulmethodfor the synthesisof alkyl #enzenes0mi:ed ketones.

Dra1bac+s of Friedel-Crafts al+$lation% a.It is difficult to sto"the reaction when one

alkyl grou"has entered the ring, di 0 trialkyl#enzenes are also form.

b.The alkyl grou"often tends to rearrange. e.g., (hen #enzene is treated with n*"ro"yl

chloride, the "roduct is iso"ro"yl#enzenerather than the e:"ected n*"ro"yl#enzene.


9/14

;

**. Friedel-Crafts Ac$lation

The reaction of an acyl halidewith #enzene in

the"resenceof ewis acid lCl'! is called 3

Ste# .The electro"hile attacks the #enzene

ring to form a car#onium ion.

4


11/14

11

Ste# 0.oss of "roton gi$es an aromatic

ketone.

Adanta'es%

a.?o Polyacylated "roducts are formed. b.?o rearrangement "roducts are formed.


12/14

12

A##lications%

a.romatic ketonescan #e "re"ared.

b.n*"ro"yle #enzenecan #e "re"ared which is

a @Clemenson Aeduction.

CH2CH2CH3

Benzenen*

Pro"yl#enzene


13/14

1'

2ther *nd!strial A##lications

Toluene is a common sol$ent, e.g. for"aints,

"aint thinners, silicone sealants, many chemical

reactants, ru##er,"rinting ink, adhesi$esglues!,

lacuers, leather tanners, and disinfectants.


14/14

1&

References

A TEXT BOOK OF ORGANIC CHEMISTRY

BY B.S. Bahl.

A TEXT BOOK OF ORGANIC CHEMISTRY

BY M. YOUNAS.

&e1is acid% s!bstance forin' coalent bond% a su#stance that can acce"t a "air of

electrons from a #ase to form a co$alent #ond.

Carboni! ion% or'anic ion% that has a car#on atom #earing a "ositi$e charge.

Aceto#henone% colorless li3!id cheical% with a sweet "ungent smell and taste. Dse

"erfumes, sol$ent, fla$oring.

Friedel Craft Reaction-4.Ppt (1)

Documents

Transcript of Friedel Craft Reaction-4.Ppt (1)