NMR-STUDIES OF N-(BENZIMIDAZOL-2-YL)PYRIDINIUM DERIVATIVES - QSAR WITH THE ANTILEISHMANIAL ACTIVITY AND THEIR C-13 NMR CHEMICAL-SHIFTS

Quantitative structure-activity - relationships between the in vitro anti-leishmanial activity of N-benzimidazolyl-2,4,6-triphenylpyridinium salts 6 and pyridinium benzimidazolate betaines 7 and their C-13-NMR chemical shifts have been studied, in order to ascertain the influence of the benzimidazole substituents upon anti-leishmanial activity. The calculated C-13-chemical shifts allow the selection of a representative subset of compounds. Several new N-benzimidazolylpyridinium derivatives 6 and 7 have been prepared. Among them, 5-methoxy-1-methylbenzimidazole 21 and 6-methoxy-1-methylbenzimidazole 22 derivatives have high anti-leishmanial activity in vitro and compound 22 shows an interesting activity in vivo although host toxicity is present.