UG

1. “ Heterocyclic and Polycyclic
Aromatic Compound”
G. P. Sadawarte
Assistant Professor
Dept. of Chemistry,
B.P. Arts, S.M.A. Science, K.K.C. Commerce
College Chalisgaon

2. Introduction
• Cyclic or ring Compound Contain C & H -
Homocyclic
• Cyclic or ring Compound Contain at least one
Heteroatom like S, O and N
• Alkaloids, Colouring Matter, Vegetables
• Five or Six membered Compound
• Furan, Thiophene, Pyrrole
• Pyridine
• Quinoline, Indole, Benzofuran

3. Heterocyclic Compound
This are cyclic rings compound containing at least
one hetero atom other than carbon .
N
H
S O
Pyrrole Thiophene
N N
Quinoline Isoquinoline
Pyridine
N
Furan

4. Numbering
N S O
Pyrrole Thiophene
N N
Quinoline Isoquinoline
Pyridine
N
Furan
2
3
4
5
1 1
2
3
4
5
alpha
beta
1
2
3
4
5
6
1
2
3
4
5
6
7
8

5. Example
O
NO2 S
NO2
N
Br
N
Br
N
1
2
3
4
5
6
7
8
Br
N
N
1
2
3
4
5
6
7
8
2-Nitro furan 3-Nitro thiophene 3-Bromo pyridine 3-Bromo pyridine
8-Bromo quinoline
5-Methyl quinoline
1-Methyl isoquinoline

6. Furan(C4H4O)
• Furan is a Heterocyclic organic compound.
• Having five member aromatic ring with four
carbon atoms and one oxygen.
• Furan is a colorless, flammable, highly volatile
liquid with a boiling point close to room
temperature.
• It is soluble in common organic solvents,
including alcohol, ether, and acetone, and is
slightly soluble in water.
• Its odor is strong, ethereal; chloroform like.
• It is toxic and may be carcinogenic in humans.

7. Aramaticity
• Compound must be cyclic and Planer.
• Every atom in the ring must be conjugated.
• Molecule must have [4n+2] pi electrons
• Where n=0,1,2,3,……..n
• Cyclic and planer
• Conjugated
• 3 pi Bond i.e. 6 pi electron
• n =0 -------?
• n= 1--------?

8. Aramaticity

9. Synthesis of Furan
O
CHO
Steam Distillation
Oxide Catalyst O
+ CO2
From Furfural
Fufural Furan

10. Synthesis of Furan
From Mucic Acid
CO2
CHOH
HOHC
CHOH HOHC
HOOC COOH
Dry Distillation
O
COOH
Mucic Acid
- H2O
-
2-Furoic Acid
O
COOH
Boil
Decarboxylation
O
+ CO2
2-Furoic Acid
Furan

11. Electrophonic substitution

12. Reaction of Furan
Sulphonation
O
O
+ SO3
Pyridine
SO3H
2-Furan sulphonic Acid
O
O
+ CH3COCl
COCH3
2-Acetyl Furan
AlCl3
Furan
Furan Acetyl Chloride
Sulphurtrioxide
Fridal Crafts Acylation

13. Reaction of Furan
O
O
+ CHCl3
CHO
Furfual
KOH
Furan Chloroform
Reimer Tiemann Reaction
O
O
+ HNO3
NO2
2-Nitrofuran
Acetic unhydride
Furan Nitric Acid
Nitration
100
C

14. Reaction of Furan
O
O
+ H2
Tetra Hydra Furan
Ni
Furan
Reduction
Hydrogenation

15. Thiophene (C4H4S)
•Thiophene is a heterocyclic compound
•It is a planar five-membered ring.
• It is aromatic as indicated by its extensive
substitution reactions
•It is a colorless liquid with a benzene like odor.
S
Thiophene

16. Synthesis of Thiophene
• From n-Butane
• From Acetylene
Heat
S
+ 3 H2S
+ 4 S
600 o
C
HC CH + H2S
Al2O3
600 o
C
S
+
H2
2

17. Reaction of Thiophene
Sulphonation
S S
+ H2SO4
SO3H
2-Thiophene sulphonic Acid
S
S
+ CH3COCl
COCH3
2-Acetyl Thiophene
AlCl3
Thiophene
Thiophene Acetyl Chloride
Sulphuric Acid
Fridal Crafts Acylation

18. Reaction of Thiophene
S S
+ CHCl3
CHO
Thiophene 2-Carboxyaldehyde
KOH
Thiophene Chloroform
Reimer Tiemann Reaction
S S
+ HNO3
NO2
2-Nitro Thiophene
Acetic unhydride
Thiophene Nitric Acid
Nitration
10o
C

19. Reaction of Thiophene
S S
+ H2
Tetra Hydra Thiophene
Ni
Thiophene
Reduction
Hydrogenation

20. Synthesis of Pyrrole
HC CH + H3N
Heat
Red hot tube
H
+
H2
2
H
O Stem N
+ H2O
+ H3N
Al2O3
H
From Acetylene
From Furan

21. Reaction of Pyrrole
Sulphonation
N
H
N
H
+ H2SO4
SO3H
2-Pyrrole sulphonic Acid
Pyrrole Sulphurtric Acid
N
H
N
H
+ CH3COCl
COCH3
2-Acetyl Pyrrole
AlCl3
Pyrrole Acetyl Chloride
Fridal Crafts Acylation

22. Reaction of Pyrrole
N
H
N
H
+ CHCl3
CHO
Pyrrole 2- Carboxyaldehyde
KOH
Pyrrole Chloroform
Reimer Tiemann Reaction
N
H
N
H
+ HNO3
NO2
2-Nitro Pyrrole
Acetic unhydride
Pyrrole Nitric Acid
Nitration
5o
C

23. Reaction of Pyrrole
N
H
N
H
+ H2
Pyrrolidine
Ni
Reduction
Hydrogenation
Pyrrole

24. Pyridine(C5H5N)
• Pyridine is a basic Heterocyclic organic Compound
• It is structurally similer to bnzene, with one methine
group (=CH-) replaced by nitrogen atom
• It is a highly flammable weakly alkaline,
• unpleasant fish-like smell.
• it is colorless, but older or impure samples can appear
yellow.
• The pyridine ring occurs in many important
compounds, including agrochemicals,
pharmaceuticals, and Vitamins.
• It was produced from coal tar.

25. Synthesis of Pyridine
From Acrolein
H2C CH CHO Heat
NH3
N
CH3
K2Cr2O7
dil H2SO4
N
COOH
3- Methyl Pyridine 3- Pyridine Carboxylic acid
N
CaO
Heat
COOH
N
3- Pyridine Carboxylic acid Pyridine

26. Synthesis of Pyridine
From Acetylene
HC CH + HCN
Heat
Red Hot Tube
2
N
From Acetylene
Acetylene

27. Reaction of Pyridine
Sulphonation
+ H2SO4
3-Pyridine Sulphonic Acid
Sulphuric Acid
N
350 o
C
Heat
N
SO3H
Pyridine
Nitration
+ HNO3
3-Nitro Pyridine
Nitric Acid
N
300o
C
N
NO2
Pyridine
H2SO4

28. Reaction of Pyridine
Halogenation
+ Br2
3-Bromo Pyridine
Nitric Acid
N
300o
C
N
Br
Pyridine
Heat +
N
Br
Br
3,5 Dibromo Pyridine
+ H2
Ni
Reduction
Hydrogenation
N
Pyridine
N
H
Piperidine
Naphthalene

29. Naphthalene(C10 H8)
•fused pair of benzene
•It is the simplest polycyclic aromatic hydrocarbon
•white crystalline solid with a characteristic odour
that is detectable at concentrations
• It is main ingredient of traditional mothballs
•it had been derived from a kind of naphtha
1
2
3
4
5
6
7
8
1/4/5/8= alpha
2/3/6/7=beta

30. NOMENCLATURE
OH
OH
NH2
Alpha- Naphthal Beta- Naphthal Alpha- Naphthyl Amine
1-Hydroxy Naphtahalene
OR
2-Hydroxy Naphtahalene 1-Amino Naphtahalene
OR OR
SO3H NH2
Alpha- Naphthalene Sulphonic Acid
1,5 - Dinitro Naphthalene
2- Naphthalene Sulphonic Acid
OR
2,4-Dinitro-1- Naphthyl amine
NO2
NO2
NO2
NO2

31. Resonanace
Naphthalene
It is planar, like benzene.
carbon–carbon bonds are not of the same length.
The bonds C1−C2, C3−C4, C5−C6 and C7−C8 are
about 1.37 Å (137 pm) in length, whereas the other
carbon–carbon bonds are about 1.42 Å long.
This difference, established by X-ray diffraction
three resonance structures.
Ref:Cruickshank, D. W. J.; Sparks, R. A. (18 October 1960). "Experimental and Theoretical
Determinations of Bond Lengths in Naphthalene, Anthracene and Other Hydrocarbons

32. Synthesis of Naphthalene
O
O
O
+
AlCl3
F.C. Acylation
HOOC
O
HOOC
Zn/Hg
HCl
Benzene beta-Benzoyl
Propanoic Acid
H2SO4
Poly
Phosphoric
acid
O
Zn/Hg
HCl
alpha-Tetralone
Tetralene
Pd/Heat
-2H2
Naphthalene
Haworth Synthesis
Succinic
Anhydride

33. Reaction of Naphthalene
O2,V2O5
460-480 o
C
O
O
O
Naphthalene
Phthalic
anhydride
CrO3,CH3COOH
25 o
C
Naphthalene
O
O
1,4-Naphthaquinone

34. Reaction of Naphthalene
NO2
HNO3/H2SO4
50-60 o
C
1 -Nitro Naphthalene
Naphthalene
Nitration

35. Reaction of Naphthalene
Halogenation
Naphthalene
Conc. H2SO4
300 o
C
+ Br2
Br
1 -Bromo Naphthalene
Naphthalene
Conc. H2SO4
300 o
C
+ Cl2
Cl
1 -Chloro Naphthalene

36. Reaction of Naphthalene
Sulphonation
80 o
C
Naphthalene
1- Naphthalene Sulphonic Acid
H2SO4
SO3H
160 o
C
Naphthalene
2-Naphthalene Sulphonic Acid
H2SO4
SO3H

37. Reaction of Naphthalene
1 -Acetyl Naphthalene
Naphthalene
Fridel Crafts Acylation
+ CH3COCl AlCl3
CS2/ CCl4/ C2H2Cl4
COCH3
2 -Acetyl Naphthalene
Naphthalene
+ CH3COCl AlCl3
COCH3
C6H5NO2

38. Reaction of Naphthalene
Decahydro Naphthalene / Decalin
Naphthalene
H2/Ni
Heat
Reduction

39. Reaction of Naphthalene
Naphthalene
1,4-Dihydro Naphthalene
Na/C2H5OH
1,2,3,4- Tetrahydro Naphthalene
Reflux
Naphthalene
Na/C2H5OH
Reflux
Reduction