Synthesis of some novel N-alkyl/acyl/aroyl 2-(chroman/6-bromochroman-2-yl)-1H-benzimidazoles using ionic liquids and their antibacterial activity

Synthesis of some novel N‐substituted 2‐(chroman/6‐bromochroman‐2‐yl)‐1H‐benzimidazoles by the condensation of 3,4‐dihydro‐2H‐chroman‐2‐carboxylic acid and 6‐bromo‐3,4‐dihydro‐2H‐chroman‐2‐carboxylic acid with o‐phenylenediamine in ionic liquid (IL) [bmim]BF4 and subsequent reactions at the benzimidazole‐NH with different types of electrophiles in ILs [bmim]BF4 = 1‐butyl‐3‐methylimidazolium tetrafluoroborate, [bmim]PF6 = 1‐butyl‐3‐methylimidazolium hexafluorophosphate and [buPy]BF4 = butylpyridinium tetrafluoroborate in the presence of sodium hydroxide as a base have been reported. All the synthesized compounds were screened for their antibacterial activity. Some compounds exhibited promising antibacterial activity against Staphylococcus aureus and Salmonella typhimurium when compared to Cephalexin as a reference standard. J. Heterocyclic Chem., (2010).