Schiff base

Encyclopedia : S : SC : SCH : Schiff base

a mixture of 4,4'-diaminodiphenyl ether 1 (1.00 g, 5.00 mmol) and o-vanillin 2 (1.52 g , 10.00 mmol) in methanol (40.00 mL) is stirred at room temperature for one hour to give an orange precipitate and after filtration and washing with methanol to give the pure Schiff base 3 (2.27 g, 97.00 %)

A Schiff base (or Schiff's base) is a functional group or type of chemical compound containing a carbon-nitrogen double bond with the nitrogen atom connected to a aryl group or an alkyl group but not hydrogen. The Schiff base is named after Hugo Schiff.

R₁R₂C=N-R₃

R₃ stands for a phenyl or alkyl group which makes the Schiff base a stable imine. Schiff bases can be synthesised from an aromatic amine and a carbonyl compound in a nucleophilic addition to a hemiaminal followed elimination of water to the imine. The Schiff base is synonymous with an azomethine. In a typical reaction 4,4'-diaminodiphenyl ether reacts with o-vanillin ^[1].

There is a Schiff base intermediate in the Fructose 1,6-bisphosphate aldolase catalyzed reaction during glycolysis.

Schiff Bases are also the punchline in many chemistry jokes. Take the past tense of imine synthesis: with the addition of ethanol, the reaction mixture became schiff-based.

External links

Gold Book [definition]

References

^[1] Synthesis of 2-(phenoxy)phenyl]imino}methyl)- 6 -methoxy phenol A. A. jarrahpour, M. Zarei Molbank 2004, M352 [link] open access publication.

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