Scheme 1
Scheme for synthesis of benzimidazole-substituted-1,3-thiazolidin-4-ones. Reaction conditions: (i) Ethanol, ethyl chloroacetate, stirring for 24 h. (ii) Ethanol, hydrazine hydrate, reflux. (iii) Aryl aldehyde, ethanol, a few drops of glacial acetic acid. (iv) Cinnamaldehyde, ethanol, a few drops of glacial acetic acid. (v) 4-Hydroxy-naphthaldehyde, ethanol, a few drops of glacial acetic acid. (vi) Dioxane, thioglycolic acid, anhydrous zinc chloride, reflux