An efficient and easy procedure is developed for the synthesis of isatin aldazines or bis-Schiff bases of isatin, catalyzed by a proton exchanged Algerian montmorillonite clay (MMT-H + ) as green catalyst. The products were obtained in two catalyzed steps under conventional heating in ethanol. Isatin-3hydrazone obtained from the reaction of isatin with hydrazine monohydrate reacts in the second step with the appropriate aromatic aldehydes to give the desired products in good yields. The main advantages of using this protonated solid non-toxic catalyst in this synthesis are its availability and low cost, the simplicity of its use, the recycling possibilities without significant loss of its catalytic activity and its environmentally benign process. ] and also considered as corrosion inhibitors [20]. Synthesis of isatin-based azines are generally made by condensation of 3-hydrazinoindolin-2-one with aldehydes or ketones to yield respectively isatin aldazines (R1 or R2 = H) or isatin ketazines (R1 and R2 ≠ H) [21]. Most of these synthesis are based mainly on traditional thermal methods in presence of organic solvents and a range of catalysts, such as: acetic acid [22], HCl [23], triethyl amine [24], FeCl3.6H2O [25],
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