Procedure for the synthesis of coumarin prepared by Sowmya B U

1. Synthesis of
7-Hydroxy-4-Methyl Coumarin
Prepared By
SOWMYA B U
Ⅱ M.Sc. Ⅳ Semester
Department of Studies and Research in Organic Chemistry
Tumkur University, Tumakuru

2. To synthesize 7-Hydroxy-4-Methyl Coumarin by the reaction of
Resorcinol and Ethyl acetoacetate in presence of conc. H2SO4.
Coumarins are made of fused Benzene and Pyrone ring. These are
present in significant amount in plants and more than 1300
Coumarins have been isolated from natural sources.
Coumarins possess remarkable and broad medicinal applications like
antimicrobial, antitumour and anticoagulants etc. Coumarin can be
synthesized by several routes including Pechmann, Perkin,
Knoevenagel and Reformatsky reactions. The Pechmann
condensation reaction of a phenol with a β-ketoester in presence of an
acid condensing agent is a valuable synthetic method.
Principle
Aim

3.  Resorcinol
 Ethyl acetoacetate
 Conc. H2SO4
 NaOH
 Conical flask
 Beaker
 Dropper
 Glass rod
 Thermometer
 Filter paper
 Filter funnel
 Watch glass
Chemicals required; Apparatus required;

4. Procedure
Cool 7 ml of conc. H2SO4 in 50 ml conical flask in an ice bath until
the temperature reaches below 5°C.
When temperature falls below 5°C add solution of 1 g of resorcinol
in 1.75 g (≈ 2 ml) of ethyl acetoacetate dropwise with constant
stirring.
Maintain the temperature below 10°C during the addition (30
minutes).
Keep the reaction mixture at lab temperature for 24 hr and then
pour the reaction mixture on to the crushed ice.

5. Collect the precipitate and wash it with cold water
Dissolve the precipitate in 1N NaOH filter and add 1N H2SO4 with
vigorous stirring till the solution is acidic to litmus.
Filter the crude 7-hydroxy-4-methyl coumarin, wash with cold
water and dry.
Report the yield of crude product.
Recrystallisation: Recrystallise the product from ethanol.

6. Reaction
Calculation
Amount Molecular
Weight
Moles Equivalents
Resorcinol 1 g 110.1 g 0.009 1
Ethyl aceto -
acetate
1.756 g
(or) 1.72 ml
130.14 g
(d =1.02
g/cm3)
0.0135 1.5

7. Percentage yield
Theoretical yield:
110 g of Resorcinol forms 176 g of 7-Hydroxy-4-Methyl Coumarin
1 g of Resorcinol forms ‘x’ g of 7-Hydroxy-4-Methyl Coumarin
x = 1×176/110
x = 1.6 g
Practical yield = …………g
Percentage yield = (Practical yield/Theoretical yield)×100
= ……………%

8. Mechanism

9. Importance of Coumarins
Coumarins
Anticancer
Antineurodegenerative
Antibacterial
Antifungal
Antiviral
Fluorescent
sensors
Anti inflammatory
Anti diabetic
Anticoagulant
Antioxidant

10. Structure and Name of
the compound
Theoretical
yield
Practical
yield
Percentage
yield
Theoretical
melting
point
Report
Thank You