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The Burkholderia genus offers a promising potential in medicine because of the diversity of biologically active natural products encoded in its genome. Some pathogenic Burkholderia spp. biosynthesize a specific class of antimicrobial 2-alkyl-4(1H)-quinolo

Drug-resistant malarial strains have been continuously emerging recently, which posts a great challenge for the global health. Therefore, new antimalarial drugs with novel targeting mechanisms are urgently needed for fighting drug-resistant malaria. NADH-ubiquinone oxidoreductase of Plasmodium falciparum (PfNDH2) represents a viable target for antimalarial drug development. However, the absence of structural information on PfNDH2 limited rational drug design and further development. Herein, we report high resolution crystal structures of the PfNDH2 protein for the first time in Apo-, NADH-, and RYL-552 (a new inhibitor)-bound states. The PfNDH2 inhibitor exhibits excellent potency against both drug-resistant strains in vitro and parasite-infected mice in vivo via a potential allosteric mechanism. Furthermore, it was found that the inhibitor can be used in combination with dihydroartemisinin (DHA) synergistically. These findings not only are important for malarial PfNDH2 protein-based drug development but could also have broad implications for other NDH2-containing pathogenic microorganisms such as Mycobacterium tuberculosis.

A high-throughput screen (HTS) was undertaken against the respiratory chain dehydrogenase component, NADH:menaquinone oxidoreductase (Ndh) of Mycobacterium tuberculosis (Mtb). The 11000 compounds were selected for the HTS based on the known phenothiazine Ndh inhibitors, trifluoperazine and thioridazine. Combined HTS (11000 compounds) and in-house screening of a limited number of quinolones (50 compounds) identified ～100 hits and four distinct chemotypes, the most promising of which contained the quinolone core. Subsequent Mtb screening of the complete in-house quinolone library (350 compounds) identified a further ～90 hits across three quinolone subtemplates. Quinolones containing the amine-based side chain were selected as the pharmacophore for further modification, resulting in metabolically stable quinolones effective against multi drug resistant (MDR) Mtb. The lead compound, 42a (MTC420), displays acceptable antituberculosis activity (Mtb IC50 = 525 nM, Mtb Wayne IC50 = 76 nM, and MDR Mtb patient isolates IC50 = 140 nM) and favorable pharmacokinetic and toxicological profiles.

A series of 2-pyridylquinolones has been prepared in 5-7 steps and through lead optimisation, antimalarial activity as low as 12 nM against Plasmodium falciparum (Pf) has been achieved. Compared with previous analogues in this series, selected molecules h

Abstract A series of tripodal nitrogen containing ligands including amidine and aminopyridines with extra oxazoline functionality were synthesized. The corresponding titanium complexes bearing such ligands were synthesized by diethylamine elimination rout

A program was undertaken to identify hit compounds against NADH:ubiquinone oxidoreductase (PfNDH2), a dehydrogenase of the mitochondrial electron transport chain of the malaria parasite Plasmodium falciparum. PfNDH2 has only one known inhibitor, hydroxy-2-dodecyl-4-(1H)-quinolone (HDQ), and this was used along with a range of chemoinformatics methods in the rational selection of 17 000 compounds for high-throughput screening. Twelve distinct chemotypes were identified and briefly examined leading to the selection of the quinolone core as the key target for structure-activity relationship (SAR) development. Extensive structural exploration led to the selection of 2-bisaryl 3-methyl quinolones as a series for further biological evaluation. The lead compound within this series 7-chloro-3-methyl-2-(4-(4-(trifluoromethoxy)benzyl)phenyl) quinolin-4(1H)-one (CK-2-68) has antimalarial activity against the 3D7 strain of P. falciparum of 36 nM, is selective for PfNDH2 over other respiratory enzymes (inhibitory IC50 against PfNDH2 of 16 nM), and demonstrates low cytotoxicity and high metabolic stability in the presence of human liver microsomes. This lead compound and its phosphate pro-drug have potent in vivo antimalarial activity after oral administration, consistent with the target product profile of a drug for the treatment of uncomplicated malaria. Other quinolones presented (e.g., 6d, 6f, 14e) have the capacity to inhibit both PfNDH2 and P. falciparum cytochrome bc1, and studies to determine the potential advantage of this dual-targeting effect are in progress.

Following a program undertaken to identify hit compounds against NADH:ubiquinone oxidoreductase (PfNDH2), a novel enzyme target within the malaria parasite Plasmodium falciparum, hit to lead optimization led to identification of CK-2-68, a molecule suitab

A series of amino oxazolinyl ligands were screened for palladium catalysed Heck reaction. These ligands work well as phosphine free system in aqueous, micellar medium, can be effectively recovered and reused for subsequent cycles.

A variety of ketones react with o-oxazoline-substituted anilines in the presence of catalytic amount of p-toluenesulfonic acid in dry n-butanol to form 4-amino-substituted quinolines or 4-quinolones in fair to good yields.

The syntheses and characterisation of a series of chiral and achiral 2-(aminophenyl)-2-oxazolines and some related compounds is reported. All of the derivatives have been produced by a one-step procedure involving the treatment of isatoic anhydride (i.e.

A simple and environmentally safe procedure for the preparation of 2-(o-aminophenyl)oxazolines from isatoic anhydride is presented. A series of chiral derivatives of the title compound is prepared in moderate yield via natural kaolinitic clay catalyzed re

Directed lithiation of benzamides (1), phenyloxazoline (4a), methoxymethoxybenzene (4b), and O-phenyl carbamate (4c) followed by sequential treatment with TsN3 and NaBH4 constitutes a general route to synthetically useful amino aromatics 3 and 5.