The reaction of indolizinones with dimethyl acetylenedicarboxylate gave direct access to 3′,8a-dihydrocyclopenta[hi]indolizin-8a-ol and 1H-pyrrol-3(2H)-one in good yields.

Although many quinolones have shown promise as potent antimalarials, their clinical development has been slow due to poor performance in vivo. Insights into structural modifications that can improve their therapeutic potential will be very valuable in this vibrant area of research. Our studies involving a library of quinolones which vary in substitution pattern at N1, C3, C6 and C7 positions have shown that the presence of adenine moiety at C7 can bring a noticeable improvement in activity compared to other heterocyclic groups at this location. The most potent compound emerged from this study showed IC 50 values of 0.38 μM and 0.75 μM against chloroquinesensitive and -resistant (W2) strains, respectively. Docking analysis in the Q o site of cytochrome bc1 complex revealed the contribution of a key H-bonding interaction from the adenine unit in target binding. This corroborates with compoundinduced loss of mitochondrial functions. These findings not only open avenues for further exploration of antimalarial potential of adenine-modified quinolones, but also suggests broader opportunities during lead-optimization against other antimalarial targets.

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Discovery of the biological signaling roles of H2S has spurred great interest in developing reliable methods for its accurate detection and quantification. As considerable variation in its levels is seen...

A new class of cyclazine analogues with periphery reminiscent of an aza[10]­annulene framework, tethered internally by an sp3 carbon, is presented. In depth structure analysis based on NMR and X-ray diffraction data gave a deeper insight into the effect of electron delocalization on their structure and properties. A characteristic change in chemical shift positions suggested an aromatic ring current in these systems. Attractive emission properties in solid and solution states involving charge transfer is another highlight.