Preparation and InhA inhibitory properties of novel dehydroacetic acid-derived thiazoles

A series of 4-hydroxy-6-methyl-3-(1-(4-(aryl/methyl)thiazol-2-yl)-1H-pyrazol-3-yl)-2H-pyran-2-ones 3a–h have been synthesized from aryl/methyl halomethylketones and a key pyrazole intermediate 1 using a convenient one-pot synthesis method. All compounds were characterized by NMR and MS, and the structure of three of them (3a, 3b and 3f) was resolved by X-ray diffraction. These heteroatom-rich thiazole compounds were then evaluated as inhibitors of Mycobacterium tuberculosis InhA, a key enzyme involved in the type II fatty acid biosynthesis pathway of the mycobacterium. Although inhibitory activities were found to be rather weak, molecular docking studies were also been carried out to understand a possible mode of interaction with key residues in the enzyme’s active site.