Papers of the Week

Chemoselective O-alkylation of 1-aryl-3-polyfluoroalkylpyrazol-5-oles under basic conditions resulted in a series of 5-alkoxypyrazoles (26 derivatives). They were showed to have an acceptable ADME profile (in silico). In experiments in vivo (CD-1 mice), it was found that the obtained compounds do not have toxic properties at a dose of more than 150 mg/kg (for most compounds at a dose of > 300 mg/kg, and for lead compounds – > 600 mg/kg). 22 Compounds demonstrated from moderate to high analgesic effects (28-104% at 1 h and 37 -109% at 2 h after administration) in vivo in the hot plate test (SD rats, 15 mg/kg, intraperitoneal (ip)). The lead compound was 4-([1-phenyl-3-(trifluoromethyl)pyrazol-5-yl]oxy)butan-1-ol, which not only increased the latent period in the hot plate test by 103% at both time investigation points but also showed a pronounced analgesic effect under conditions of capsaicin-induced nociception (CD-1 mice, 15 mg/kg, ip). According to molecular modeling, all synthesized compounds can interact with the TRPV1 ion channel. This biological target was confirmed in in vitro experiments on Chinese hamster ovary cells expressing rTRPV1. 5-Alkoxypyrazoles were partial agonists of the TRPV1 ion channel in various degree, and the most active was the same pyrazole as in in vivo tests.