title: Synthesis and biological activity of 1H-benzotriazole and 1H-benzimidazole analogues--inhibitors of the NTpase/helicase of HCV and of some related Flaviviridae.
abstract: To improve anti-helical activity of analogues of 1H-benzotriazole and 1H-benzimidazole their N-alkyl derivatives were synthesized and tested for antihelicase activity against enzymes of selected Flaviviridae including hepatitis C virus (HCV), West Nile virus (WNV), Dengue virus (DENV) and Japanese encephalitis virus (JEV). 1- and 2-alkyl derivatives of 4,5,6,7-tetrabromo-1H-benzotriazole were obtained by direct alkylation of 4,5,6,7-tetrabromo-1H-benzotriazole with the use of respective alkyl halides in the presence of KOH in methanol, to give a mixture of 1- and 2- isomers, which was separated by flash column chromatography in good yield. The proportion of isomers strongly depended on the reaction time and temperature. 1- and 2-hydroxyethyl and 1- and 2-chloroethyl derivatives of the tetrabromobenzo-triazole were synthesized with the use of 2-bromoethanol and 1-bromo-2-chloroethane respectively as alkylating agents. N-alkylation of this benzotriazole compound enhanced inhibitory activity and selectivity towards the helicase activity of HCV NTPase/helicase. The most active were the 2-methyl, 2-ethyl and 2-propyl derivatives (IC50 approximately 6.5 microM in the presence of DNA as a substrate). Derivatives of the benzotriazole in which hydroxyethyl or chloroethyl replaced the alkyl substituents lost their inhibitory activity. Brominated or methylated benzotriazole N(1) ribosides also did not exert helicase inhibitory activity. Although a number of N(1) and N(2) alkyl derivatives exerted good HCV and WNV helicase inhibitory activity when DNA was used as substrate, the activity was strongly decreased or even disappeared when RNA was used as substrate. The cytotoxicity tests in Vero and HeLa Tat cells showed a substantial decrease of cytotoxicity of N-alkyl derivatives as compared to the parent benzotriazole.
authors.affiliation: Institut Biochemii i Biofizyki, Polska Akademia Nauk, Warszawa, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Bretner
authors.forename: Andrea
authors.initials: A
authors.lastname: Baier
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kopańska
authors.forename: Andzelika
authors.initials: A
authors.lastname: Najda
authors.forename: Anna
authors.initials: A
authors.lastname: Schoof
authors.forename: Michael
authors.initials: M
authors.lastname: Reinholz
authors.forename: Andrzej
authors.initials: A
authors.lastname: Lipniacki
authors.forename: Andrzej
authors.initials: A
authors.lastname: Piasek
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Kulikowski
authors.forename: Peter
authors.initials: P
authors.lastname: Borowski
mesh_terms: D001562:Benzimidazoles / Q000138:chemical synthesis* / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology*; D018067:Flaviviridae / Q000201:enzymology*; D016174:Hepacivirus / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D043583:Nucleoside-Triphosphatase / Q000037:antagonists & inhibitors*; D020365:RNA Helicases / Q000037:antagonists & inhibitors*; D013056:Spectrophotometry, Ultraviolet; D014230:Triazoles / Q000138:chemical synthesis* / Q000494:pharmacology*
chemical_list: D001562:Benzimidazoles; D004791:Enzyme Inhibitors; D014230:Triazoles; C012771:benzotriazole; C031000:benzimidazole; D043583:Nucleoside-Triphosphatase; D020365:RNA Helicases