This document discusses the properties and synthesis of pyrrole. Pyrrole is a colorless liquid that is weakly basic and more reactive than benzene. It undergoes electrophilic substitution reactions like halogenation and nitration. Pyrrole can be synthesized through various methods, including from furan over an alumina catalyst, from succinaldehyde and ammonia in a condensation reaction, and by passing acetylene and ammonia through a hot tube. Pyrrole has medicinal uses including in cardiac medications and as an antibacterial, antipsychotic, and anticancer agent.

1. • Introduction: pyrrole
• Physical properties
• Chemical properties
• Synthesis of pyrrole
• reactions of pyrole
•medicinal uses

2.  It is a colourless volatile liquid.
 It’s boiling point is 131°C and melting point is -
23°C.
 It turns brown in the air and gradually resinifies.
 Only slightly soluble in water but it is totally
miscible with ether and ethanol.
 Pyrrole is weakly basic in nature.
 Pyrrole has a relatively high boiling point as
compared to furan and thiophene, this is due to
the presence of intermolecular hydrogen bonding
in pyrrole. vwa

3.  Pyrrole is aromatic and more reactive than
benzene.
 It gives electrophilic substitution reactions
such as halogenation , nitration ,etc.
 It also undergoes diazotization and
Reimer-Tiemann reactions, while benzene
does not.

4.  From furan
 By heating a mixture of furan, ammonia and
steam over alumina catalyst .

5.  It is a condensation reaction between 1,4-
dicarbonyl compound with ammonia or a primary
amine to form a substituted pyrrole. Pyrrole itself is
formed from succinaldehyde and ammonia.

7.  The hantzsh pyrrole synthesis is the reaction of
beta-ketoester with ammonia (or primary amine)
and alpha-haloketones to give substituted pyrrole.

9.  Pyrrole is obtained by the distillation of
succinimide with zinc dust.

10.  Pyrrole is obtained by passing acetylene and
ammonia through a red hot tube.
acetylene Ammonia

11.  Acylation
 Pyrrole treated with acetic anhydride at 200°C gives
2 – acetyl pyrrole while N – acetyl pyrrole can be
obtained by heating pyrrole with N –
acetylimidazole.

12.  Pyrrole is oxidized to maleinimide and on reduction
it gives pyrrolidine.

13.  When potassium pyrrole is heated with chloroform
and sodium ethoxide, the pyrrole (five – membered
ring) expands to pyridine (six-membered ring).

14.  In the presence of a strong base and chloroform,
pyrrole undergoes Reimer – Tiemann reaction to
form pyrrole – 2 – aldehyde.

15.  Pyrrole may be formylated by heating it with
phosphorus oxychloride and dimethyl formamide.
The intermediate is hydrolyzed in the presence of a
mild base to 2 – pyrrole carbaldehyde.

16.  Electrophilic substitution:
The electrophilic substitution takes place preferably
at C2 or C5 – positions. If these positions are
already occupied then substitution takes place at
C3 or C4 positions.
1.Nitration
2.Sulphonation
3.Friedal craft alkylation
4.Friedal craft acylation
5.halogenation

18. 2-nitropyrrole 3-nitropyrrole
Reaction:nitration of pyrrole results in 2 product .one is major product and
second is minor product………

19. Reaction:pyrrole is reacted with sulphuric acid in the presence of sulphuric
acid and it gives two product one is major product and one is minor
product.
2-pyrrole sulfonic
acid
3-pyrrole sulfonic
acid

20.  Reaction:pyrrole is reacted with CL2 in the presence
of ALCL3 and it gives two product one is major
product and one is minor product.
pyrrole
cl2
ALCL3
2-chloropyrrole 3-chloropyrrole

21. Reaction:pyrrole is reacted with alkyl group
in the presence of ALCL3 and it gives two
product one is major product and one is
minor product.
pyrrole 2-methylpyrrole 3-methylpyrrole
CH3-I
ALCL3

22. Reaction:pyrrole is reacted with acyl group in the
presence of ALCL3 and it gives two product one is
major product and one is minor product.
pyrrole
ch3cocl
alcl3
2-ethylpyrrole 3-ethyl pyrrole

23.  Used in narcotic industry for making tabbaco.
 Used in cardiac disease medicine .
 Used in making pyrole derivatives.
 Anti-bacterial.
 Anti-psycotic.
 Anti-malerial.
 Anti-cancer.
 Anti-muscarinic drug to treat parkinsonism.
 Anti-fungal

24.  Pyrrole itself is completely planar and have molecular
dimensions.
 The 5 Sp2 hybridised C-atom sustained 6π electron
system. From the molecular orbital standpoint is
consisting of planar pentagoan with Sp2 hybridised C-
atoms.
 Each of the 4 C-atoms has one electron remaning in a
pz orbital. The N-atom has 2 electron in p orbital.
 These p orbitals overlap to give a total of six electrons
in π system and this shell provide stability.
 Pyrrole is an extremely weak base because its pair of
non-bonding electrons are part of the π-cloud (Kb =
2.5 x 10-14). Therefore, if pyrrole is protonated, it
loses its aromaticity.