Structural simplification of the 3‐nitroimidazo[1,2‐ a ]pyridine antileishmanial pharmacophore: Design, synthesis, and antileishmanial activity of novel 2,4-disubstituted 5-nitroimidazoles

• Published in: Heterocyclic Communications Vol. 30; no. 1; pp. 312 - 25
• Main Authors: Paoli-Lombardo, Romain, Primas, Nicolas, Hutter, Sébastien, Castera-Ducros, Caroline, Jacquet, Inès, Verhaeghe, P., Azas, Nadine, Rathelot, Pascal, Vanelle, Patrice
• Format: Journal Article
• Language: English
• Published: de Gruyter 05-08-2024; De Gruyter
• Subjects: 5-nitroimidazole; antileishmanial activity; Bacteriology; Cardiology and cardiovascular system; Emerging diseases; Human health and pathology; Infectious diseases; Life Sciences; Microbiology and Parasitology; Parasitology; structural simplification; tetrakis(dimethylamino)ethylene (tdae); vicarious nucleophilic substitution (vns); Virology; 5-nitroimidazole; vicarious nucleophilic substitution (VNS); tetrakis(dimethylamino) ethylene (TDAE); structural simplification; antileishmanial activity
• ISSN: 0793-0283; 2191-0197
• DOI: 10.1515/hc-2022-0176

As part of our ongoing antileishmanial structure–activity relationship study, a structural simplification of the 3‐nitroimidazo[1,2‐ a ]pyridine ring to a 5-nitroimidazole moiety was conducted. A series of novel 2,4-disubsituted 5-nitroimidazole derivatives, including the 5-nitroimidazole analog of Hit A and the 4-phenylsulfonylmethyl analog of fexinidazole, were obtained by using the vicarious nucleophilic substitution of hydrogen (VNS) reaction, to substitute position 4, and by using the tetrakis(dimethylamino)ethylene methodology to modulate position 2. The molecular structures of eight novel 5-nitroimidazoles were characterized by 1 H NMR, 13 C NMR, LC/MS, and HRMS. The in vitro antileishmanial activity of these compounds was evaluated against the promastigote form of Leishmania infantum and their influence on cell viability was assessed on the human hepatocyte HepG2 cell line. The 4-phenylsulfonylmethyl analog of fexinidazole showed the best selectivity index of the series, displaying good activity against both the promastigote form of L. infantum (EC 50 = 0.8 µM, SI > 78.1) and the promastigote form of Leishmania donovani (EC 50 = 4.6 µM, SI > 13.6), and exhibiting low cytotoxicity on the HepG2 cell line (CC 50 > 62.5 µM).