Page 29 - Practical-organic-3
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Procedure of 3-Methyl-pyrazolinone Synthesis
◼ In an ice bath, cool the hydrazine hydrate and ethyl acetoacetate for 10 min.
◼ In an ice bath cooled round bottom flask add ethyl acetoacetate (1 ml).
◼ Then add 4 drops of hydrazine hydrate dropwise slowly while protecting your
face by glasses and face mask.
◼ Leave the flask in the ice bath for an additional 10 minutes where a white ppt of
3-methyl-pyrazolinone is formed.
◼ To purify the product:
1. Wash with ethanol (10 ml) to get rid of any byproduct.
2. Filter out the produced 3-methyl-pyrazolinone.
⁂ Cooling by an ice bath is essential in this reaction due to:
1. The highly exothermic nature of this reaction.
2. Hydrazine is a highly reactive compound.
Reaction Name & Mechanism
Reaction Name: Paal-Knorr.
◼ Condensation occurs to give hydrazone (C=N-NH2) then (ethanol) is removed.
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