Introduction to Perkin reaction its mechanism and examples.pdf

Perkin reaction

1. PERKIN REACTION

2. Department of Chemistry
Course Title: Designing Organic Synthesis
Course Code: Chem-5114
Semester: 2
nd
(MS Chemistry)
Submitted to: Dr. Munazza Shahid
Submitted by: Rida Tahreeem
Roll Number: msf-23001833
Perkin Reaction

3. Contents
oIntroduction
oDefinition
oGeneral reaction
oMechanism of reaction
oSteps of reaction
oExamples of Perkin reaction
oApplications of Perkin reaction
oLimitation of Perkin reaction
oReferences

4. 1. Introduction:
English Chemist:
William Henry Perkin
Discovery:
19
th
century

5. 2. Definition:
ThePerkinreactiongivesanalpha,beta-unsaturatedaromaticacidviathealdol
condensationofanaromaticaldehydeandanacidanhydride.Thealkalisaltof
theacidisalsopresent.Thisalkalisaltactsasabasecatalyst.Otherbasescanbe
usedinsteadofthealkalisaltoftheacidinthePerkinreaction.
ThePerkinreactionisanaldolcondensationreactionthatisusedtomake
Cinnamicacid
Perkinreactionisanorganicreaction,thisreactionbelongstocarbonyl
compounds

6. CinnamicAcid:
Itisacarboxylicacidthatoccurs
naturally.Itisacrystallinecompound
thatiswhiteincolourandisslightly
solubleinwater.Itisfoundincinnamon
andsheabutter
Aldol:
Itisanabbreviationofaldehydeand
alcohol.Thealdolreaction(aldol
addition)isareactionthatcombinestwo
carbonylcompounds(aldehydesor
ketones)toformanewβ-hydroxy
carbonylcompound.

7. 3. General Reaction:
Reagents: Aromatic aldehyde, acetic anhydride
Catalyst: alkali salt of an acid anhydride,
Products: Cinnamicacid

8. 4. Mechanism of Perkin Reaction:
1: Abstraction of alpha hydrogen of acid anhydride by base
2:Attack of carbanionon carbonyl carbon of benzaldehyde
3: Intramolecularacetyl shift
4: Loss of acetate ion from beta carbon

9. Steps of Perkin Reaction:
Step 1
Abstraction of alpha hydrogen of acid anhydride by base
The anion of acid acts as a base and removes alpha hydrogen from the anhydride

10. Step 2
Attack of carbanionon carbonyl carbon of benzaldehyde
Step 3
Intramolecularacetyl shift
The migration of acetyl groups occurs via a cyclic intermediate to alkoxyoxygen

11. Step 4
Loss of acetate ion from beta carbon
In the presence of a base, alpha hydrogen is abstracted which in turn causes the removal of
good leaving group acetate ion to form alpha beta unsaturated carboxylic acid

12. 4. Examples of Perkin Reaction:
•Formation of alpha beta unsaturated acid
•Formation of methyl cinnamicacid

13. 5. Applications of Perkin Reaction:
Perkinreactionismostlyusedinthepreparationofaryl-substitutedacrylicacidsandtheir
catalytichydrogenationcangivebeta-arylderivativesofsaturatedcarboxylicacids.This
reactionisalsousedintheproductionofseveralcommerciallyimportantcompounds:
FormationofFurylacrylicacidfromFurfural,whichprovides65-70%yields.
Synthesisofphytoestrogenicstilbeneresveratrol
Cinnamicacidthatb\istheproductofperkinreactionactasanantimicrobial9
antifungal,antiviral,antibacterial)andantioxidantsproperties.Theyallareisolated
fromplantmaterial.

14. Cinnamicacidisusedtomakeethyl,methylandbenzylestersusedintheperfumeindustry
Itisusedinthesynthesisofwarfarin(anticoagulation)whichinhibitclotformationinthe
areasofslowlyrunningblood(suchasinveinsandthepooledbloodbehindartificialand
naturalvalves)
CinnamicacidiscreatedinlaboratoriesviaPerkinCondensation.Cinnamicacidsare
unsaturatedaromaticcarboxylicacidsthatarepresentincinnamonandsheabutter.
6.LimitationofPerkinReaction:
Ingeneral,thistypeofreactionisonlyapplicabletoaromaticaldehydes,andthecondensation
involvesonlytheanhydride’sα-hydrogenatoms.

15. 7. References:
https://testbook.com/chemistry/perkin-reaction-mechanism
https://www.slideshare.net/AttiqUrRehman98/perkin-reactionpdf
https://scienceinfo.com/perkin-condensation-reaction-mechanism/
https://study.com/academy/lesson/perkin-reaction-definition-mechanism.html
Smith M. & March J. (2001). March’s Advanced Organic Chemistry: Reactions
Mechanisms and Structure (5th ed.). Wiley.