Synthesis of benzimidazole

Procedure for the synthesis of benzimidazole prepared by Harshitha B N

1. TUMKUR UNIVERSITY
TUMAKURU
“PROCEDURE FOR SYNTHESIS OF BENZIMIDAZOLE”
Prepared By
HARSHITHA B.N
ⅡM.Sc. ⅣSemester
Department of Studies and Research in Organic Chemistry
Tumkur University, Tumakuru
Under the Guidance
Dr. G. KRISHNASWAMY
Faculty
Department of Studies and Research in Organic Chemistry
Tumkur University, Tumakuru
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2. AIM:TosynthesizeBenzimidazolefromO-phenylenediamine.
PRINCIPLE:Benzimidazoleisa(6+5)heterocyclicaromaticcompoundformedbythe
fusionofthebenzeneandimidazolemoiety.BenzimidazoleresemblePurinelikestructure
andelicitsomebiologicalapplication.Itexistsintwotautomericforms.
WellknownactivedrugswithBenzimidazoleringareAlbendazoleandMebendazoleused
asanthelminticdrugs.
Simplest method for the synthesis of Benzimidazole is condensation of O-
phenylenediamine (OPD) and formic acid.
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3. CHEMICALSREQUIRED:1.O-phenylenediamine
2.90%Formicacid
3.SodiumHydroxide.
APPARATUSREQUIRED:1.RoundbottomflaskorIodineflask
2.Condenser
3.Filteringfunnel
4.Filterpaper.
PROCEDURE:-
Inaroundbottomflask,1gofO-phenylenediamineistreatedwith3.48mlof90%
formicacid.
Theresultingmixturewasheatedinawaterorsandbathat100
O
Cfor2hours.
Aftercompletion,coolthereactionmixturetolabtemperatureandaddslowly10%
sodiumhydroxidesolutionwiththoroughmixinguntilthemixtureisjustalkalinetored
litmus.
TheCrudeBenzimidazoleobtainedwascollectedbyfiltrationandrinsedwithcoldwater.
Thepureproductwasobtainedbyrecrystallizationinhotwater.
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4. REACTION:
CALCULATION :-
THEORETICAL YIELD :
108.13gofO-phenylenediamineyields118.4gofBenzimidazole.
1gofO-phenylenediaminewillformsXgofBenzimidazole.
AMOUNT MOLECULAR
WEIGHT
MOLES EQUIVALENT
1. OPD 1g 108.1 0.00925 1
2. HCOOH 3.48ml 46.03
d=1.22g/ml
0.00925 10
3. 10%NaOH 10g in 100ml water
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5. 100
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6. REPORT:
APPLICATIONS:
The Benzimidazole and its derivatives play a very important role as a therapeutic agent.
For Example: Antiulcer and Anthelmintic drugs.
The Benzimidazole derivatives exhibit pharmacological activities such as antimicrobial,
antiviral, anticancer, anti-inflammatory, analgesic etc.
STRUCTURE
andNAME
THEORETICAL
YIELD
PRACTICAL
YIELD
%
YIELD
MELTING POINT
(Theoretical)
MELTING POINT
(Practical)
BENZIMIDAZOLE
1.09g 0.78g 71.4% 171 –172
O
C 170
O
C
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