Synthesis of 2-(benzylthio)benzimidazole, 2-[(benzimidazol-2-yl)methylthio]benzimidazole and structural analogues against Haemoncus contortus

The coupling of the derivatives of the 2-mercaptobenzimidazole 1 with the derivatives of the (chloromethyl)benzene 2 gives 2-(benzylthio)benzimidazole 4a-k on the one hand, and with the 2-(chloromethyl)benzimidazole 3 on the other the 2-(benzimidazolyl methylthio) benzimidazole and analogues 5a-k. We determined the structures of all synthesized compounds by Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS). The evaluation of the anthelmintic activities of these molecules on Haemonchus contortus showed that the introduction of the nitro group (NO2) in the structure causes a significant increase of the activity. Among the molecules evaluated in vitro for their anti-infectious activity, the compounds 4b, 5d, 5e, 5f and 5h revealed an activity which is comparable to that of the reference molecules (ivermectin and fenbendazole). Key  words: 2-mercaptobenzimidazole, (chloromethyl)benzene, 2-(chloromethyl) benzimidazole, 2-(methylthio) benzimidazole,  2-(benzylthio)benzimidazole, 2-(benzimidazolyl methylthio)  benzimidazole, anthelmintic, Haemonchus contortus.