1100749-90-3Relevant academic research and scientific papers
Assessment of a pretomanid analogue library for African trypanosomiasis: Hit-to-lead studies on 6-substituted 2-nitro-6,7-dihydro-5H-imidazo[2,1-b][1,3]thiazine 8-oxides
Thompson, Andrew M.,Marshall, Andrew J.,Maes, Louis,Yarlett, Nigel,Bacchi, Cyrus J.,Gaukel, Eric,Wring, Stephen A.,Launay, Delphine,Braillard, Stephanie,Chatelain, Eric,Mowbray, Charles E.,Denny, William A.
, p. 207 - 213 (2018)
A 900 compound nitroimidazole-based library derived from our pretomanid backup program with TB Alliance was screened for utility against human African trypanosomiasis (HAT) by the Drugs for Neglected Diseases initiative. Potent hits included 2-nitro-6,7-dihydro-5H-imidazo[2,1-b][1,3]thiazine 8-oxides, which surprisingly displayed good metabolic stability and excellent cell permeability. Following comprehensive mouse pharmacokinetic assessments on four hits and determination of the most active chiral form, a thiazine oxide counterpart of pretomanid (24) was identified as the best lead. With once daily oral dosing, this compound delivered complete cures in an acute infection mouse model of HAT and increased survival times in a stage 2 model, implying the need for more prolonged CNS exposure. In preliminary SAR findings, antitrypanosomal activity was reduced by removal of the benzylic methylene but enhanced through a phenylpyridine-based side chain, providing important direction for future studies.
Synthesis, reduction potentials, and antitubercular activity of ring A/B analogues of the bioreductive drug (6S)-2-nitro-6-{[4-(trifluoromethoxy)benzyl] oxy}- 6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazine (PA-824)
Thompson, Andrew M.,Blaser, Adrian,Anderson, Robert F.,Shinde, Sujata S.,Franzblau, Scott G.,Ma, Zhenkun,Denny, William A.,Palmer, Brian D.
experimental part, p. 637 - 645 (2009/12/01)
The nitroimidazooxazine S-1 (PA-824) is a new class of bioreductive drug for tuberculosis. A series of related bicyclic nitroheterocycles was synthesized, designed to have a wide range of one-electron reduction potentials E(1) (from -570 to -338 mV, compared with -534 mV for S-1). The observed E(1) values closely correlated with the om values of the heteroatom at the 4/8-position of the adjacent six-membered ring. Although the compounds spanned a range of E(1) values around that of S-1, only the nitroimidazothiazines showed significant antitubercular activity (at a similar level of potency), suggesting that E(1) is not the main driver of efficacy. Furthermore, there was a correlation between activity and the formation of imidazole ring-reduced products at the two-electron level, pointing to the potential importance of this reduction pathway, which is determined by the nature of the substituent at the 2-position of the 4-nitroimidazole ring.
