Schiff base
![General structure of a imine](/Images/godic/202412/22/Imino_Group_V.10818.png")
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![A mixture of 4,4'-oxydianiline 1 (1.00 g, 5.00 mmol) and o-vanillin 2 (1.52 g, 10.0 mmol) in methanol (40.0 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%)](/Images/godic/202412/22/Schiff_Base0818.png")
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A Schiff base is a compound with the general structure R2C=NR' (R' ≠ H). They can be considered a sub-class of imines, being either secondary ketimines or secondary aldimines depending on their structure. The term is often synonymous with azomethine which refers specifically to secondary aldimines (i.e. R-CH=NR' where R' ≠ H).