I want to synthesize triazole Schiff base ligand by refluxing 3-amino-5-mercapto-1,2,4-triazole with 2,4-dihydroxybenzaldehyde. I reflux it using distilled ethanol, added acetic acid, temp 80 C in a water bath. When I monitored it using tlc, the ligand is synthesized but still have the presence of reactants. However, no precipitate formed. I already performed column but the reactants still there.
May I know how to complete the reaction and precipitate it?
Here the tlc image, the reaction mixture in the middle and the ligand spot is in the middle between benzaldehyde (upper) and triazole (lower)
During TLC your imine target can hydrolyze back to starting materials, giving the false impression that the reaction is not complete. Analysis of the mixture by 1H NMR allows conversion to be monitored by disappearance of the aldehyde peak (ca. 10 ppm) and formation of an imine (ca. 9 ppm) counterpart. The remaining components in the mixture should not interfere with the 9-10 ppm region. After concentration, you might be able to use the crude mix in the next step to obtain a stable compound. Depending on the stability of your imine, it might also be possible to crystallize it using dry solvents or perform a rapid workup, preferably under slightly basic conditions. On occasion, an imine can survive purification by chromatography.
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