Synthesis and characterization of someN-mannich bases of [1,2,3]triazoloquinolines

Multifunctional Analogs of Kynurenic Acid for the Treatment of Alzheimer's Disease: Synthesis, Pharmacology, and Molecular Modeling Studies

We report the synthesis and pharmacological investigation of analogs of the endogenous molecule kynurenic acid (KYNA) as multifunctional agents for the treatment of Alzheimer's disease (AD). Synthesized KYNA analogs were tested for their N-methyl-d-aspartate (NMDA) receptor binding, mGluR5 binding and function, acetylcholinesterase (AChE) inhibition, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, interference with the amyloid β peptide (Aβ) fibrillation process, and protection against Aβ-induced toxicity in transgenic Caenorhabditis elegans strain GMC101 expressing full-length Aβ₄₂. Molecular modeling studies were also performed to predict the binding modes of most active compounds with NMDAR, mGluR5, and Aβ₄₂. Among the synthesized analogs, 3c, 5b, and 5c emerged as multifunctional compounds that act via multiple anti-AD mechanisms including AChE inhibition, free radical scavenging, NMDA receptor binding, mGluR5 binding, inhibition of Aβ₄₂ fibril formation, and disassembly of preformed Aβ₄₂ fibrils. Interestingly, 5c showed protection against Aβ₄₂-induced toxicity in transgenic C. elegans strain GMC101. Moreover, 5b and 5c displayed high permeability in an MDR1-MDCKII cell-based model of the blood-brain barrier (BBB). Compound 3b emerged with specific activity as a micromolar AChE inhibitor, however it had low permeability in the BBB model. This study highlights the opportunities that exist to develop analogs of endogenous molecules from the kynurenine pathway for therapeutic uses.

Synthesis and anti-mycobacterial activities of triazoloquinolones

A number of quinolone derivatives have been reported to possess anti-mycobacterial activity. Generally. Mycobacterium tuberculosis isolates expressing resistance to both isoniazid and rifampin are susceptible to fluoroquinolones. Benzotriazole is a hetero-bicyclic aromatic ring endowed with interesting chemical and biological properties and pharmacological activities. In a preliminary study we have recently reported the activity of triazolo[4,5-h]quinolone-carboxylic acids, a new class of benzotriazole derivatives active against multi-drug resistant M. tuberculosis (MDR-Mtb). In this study we confirm that this novel class of quinolones is endowed with a selective anti-mycobacterial activity, coupled with absence of cytotoxicity. The SAR analysis of the new derivatives in comparison with the previous series shows that the methyl group is the most effective substituent in both N-3 and N-9 positions of the ring system.