[double_bond]

hi

 I have done an experimet with o-phenylene diamine and salicylic acid and thus prepared 2-(2- hydroxyl)benzimidazole.The reaction was done in syrupy phosphoric acid . Actually I want to synthesise some benimidazole derivatives . In the similer way I done it with 5 nitro salicylic acid but i didn't get the product.can any one suggest the reason ? or suggest some acids with  which i can prepare the benzimidazole derivative.


 NB: reaction with o-phenylene diamine and formic acid yields benzimidazole , I am trying to do with some aromatic carboxylic acid please help me 

[wereworm73]

When you tried this reaction with the 5-nitrosalicylic acid, did you get any reaction at all? 

[double_bond]

using 5- nitro salicylic acid  I got a black product but i dont think that it is the desierd product. I refluxed o-phenylene diamine  and 5- nitro salicylic acid in syrupy phosphoric acid at 200 C  for 2 hr and poured the reaction mixture into a beaker containg 200 ml of cold water and the pH  was adjusted to 7.0  I got a black product.

[AWK]

Nitro group at elevated temperature acts as an oxidizer for o-phenylenediamine.