Synthesis of triimidazole by Radziszewski imidazole synthesis method

1. Laboratory synthesis of
triphenyl imidazole
Presented by Vaibhav Namdev (Y18150167)
Submitted to Dr. Ramkishor Agrawal
DEPARTMENT OF PHARMACEUTICAL SCIENCES
DR. HARISINGH GOUR VISHWAVIDYALAYA SAGAR MP
A CENTRAL UNIVERSITY

2. Synthesis of triphenyl imidazole
Aim :- Synthesis of 2,4,5 triphenyl imidazole.
Chemical:- benzil,ammonium
acetate,benzaldehyde, glacial acetic acid.
Principle :- triphenyl imidazole prepared by
debus radziszewski imidazole reaction used to
synthesis of imidazole from dicarbonyl,an
aldehyde and ammonia.

3. Synthesis of benzil
Synthesis of benzil
Reference Brian s.”vogal practical chemistry pg 1045

4. Synthesis of benzil
Machnism of benzil synthesis

5. Procedure for synthesis of benzil
● 20 g of benzoin and 100 ml of concentrated nitric acid are taken in a
round bottomed flask.
● heated on a boiling water bath for about 1.5 hour with occasional
shaking until the evolution of oxides of nitrogen ceases.
● The content is poured into 300 - 400 ml ice cold water with shaking.
● Then the product is filtered with suction and washed with cold water.
● It is recrystallized from ethanol, taking 2.5 ml per gram.
● For identification m.p. of benzil 94-96 °C.

6. Triphenyl imidazole

7. Synthesis reaction of triphenyl imidazole

8. Machnism of reaction

9. Machnism of reaction

10. Procedure
● Firstly take a 1 gm of benzil,1 gm of
ammonium acetate transferred in a
round bottom flask.
● Now add a 2 ml of glacial acetic acid
and 2 ml of benzaldehyde in round
bottom flask.
● Set up a reflux assembly on water
bath for heating and set the reaction
mixture for heating at 100’c
temperature.

11. Procedure
● Observe the reaction mixture while heating after a 3 to
4 hours reaction is completed.
● Completion of reaction indicates dark orange colour of
reaction mixture.
● Now allow reaction mixture to stand at room
temperature for cooling.
● Now add 150 of water.
● Now add 2 ml of ammonium hydroxide solution to
nutrilize the acid with continue stirring.
● Filter out the precipitate and dry at room temperature.

12. Identification of triphenyl imidazole
Colour :- yellowish white
Melting point: :274-278 °C(lit.)
Boiling point: :427.96°C (rough
estimated)
Solubility :Soluble in methanol.
Insoluble in water.
λmax :300nm(EtOH)(lit.)
https://pubchem.ncbi.nlm.nih.gov/compound/2_4_5-Triphenylimidaz
ole#section=3D-Conformer