6-Nitro-2,3-dihydroimidazo[2,1-b][1,3]thiazoles: Facile synthesis and comparative appraisal against tuberculosis and neglected tropical diseases

Andrew M Thompson, Adrian Blaser, Brian D Palmer, Robert F Anderson, Sujata S Shinde, Delphine Launay, Eric Chatelain, Louis Maes, Scott G Franzblau, Baojie Wan, Yuehong Wang, Zhenkun Ma, William A Denny

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14 Citations (Scopus)

Abstract

As part of a quest for backups to the antitubercular drug pretomanid (PA-824), we investigated the unexplored 6-nitro-2,3-dihydroimidazo[2,1-b][1,3]-thiazoles and related -oxazoles. The nitroimidazothiazoles were prepared in high yield from 2-bromo-4-nitroimidazole via heating with substituted thiiranes and diisopropylethylamine. Equivalent examples of these two structural classes provided broadly comparable MICs, with 2-methyl substitution and extended aryloxymethyl side chains preferred; albeit, S-oxidised thiazoles were ineffective for tuberculosis. Favourable microsomal stability data for a biaryl thiazole (45) led to its assessment in an acute Mycobacterium tuberculosis mouse model, alongside the corresponding oxazole (48), but the latter proved to be more efficacious. In vitro screening against kinetoplastid diseases revealed that nitroimidazothiazoles were inactive versus leishmaniasis but showed interesting activity, superior to that of the nitroimidazooxazoles, against Chagas disease. Overall, "thio-delamanid" (49) is regarded as the best lead.

Original languageEnglish
Pages (from-to)2583-2589
Number of pages7
JournalBioorganic & medicinal chemistry letters
Volume27
Issue number11
DOIs
Publication statusPublished - 1 Jun 2017
Externally publishedYes

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