Cyclization of thiosemicarbazone to 2 amino 1,3,4- thiadiazole methods from aromatic aldehydes.
you could apply chloroacetaldehyde or phenacyl chlorides/bromides. This is called the Hantzsch thiazole synthesis. You have to deprotonate the thiosemicarbazone first with NaOH or KOH dissolved together with the corresponding thiosemicarbazone in (eventually aqueous) ethanol. Then you can add the chloroacetaldehyde or phenacyl chlorides/bromides dissolved in acetone, and short reflux leads smoothly to N-substituted 2-aminothiazoles. You can see my paper attached (Supplement available at my profile).
There are two methods which i followed
First method is reaction of thiosemicarbazide with substituted aldehydes to give corresponding semicarbazones in the presence of alcohol.In the second step thiosemicarbazone is cyclized to corresponding amino thiadiazole in the presence of Ferric chloride.
Second method is treating substituted acids with thiosemicarbazide in the presence of ferric chloride ,which is a single step reaction
But I have tried for thiosemicarbazones with Fecl3 (anhydrous) for cyclization reaction didn't gone well Can You help me out in sending me papers for both the methods
sorry, I did not know that you wanted 1,3,4-thiadiazoles. I have an old paper about the oxidation of benzaldehyde thiosemicarbazone to 2-amino-5-phenyl-1,3,4-thiadiazole attached. The oxidation with FeCl3 in aqueous suspension at 80 °C is described there.
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