Diverse synthetic approaches towards C1'-branched acyclic nucleoside phosphonates

Exploring 4-quinolone-3-carboxamide derivatives: A versatile framework for emerging biological applications

4-Quinolones are a pivotal class of compounds derived from the quinoline core, recognized for their broad therapeutic applications. Originating from the synthesis of chloroquine, their discovery led to nalidixic acid, the first quinolone analog to exhibit antibacterial activity, catalyzing the development of fluoroquinolones. Beyond their role as antibiotics, 4-quinolone derivatives have emerged as versatile scaffolds with demonstrated antitumor, antiviral, and antiparasitic activities, among others. Concurrently, the carboxamide functional group has gained prominence in medicinal chemistry due to its structural versatility and bioisosteric potential. Its unique properties, such as conformational stability and dual hydrogen bond capabilities, enable diverse pharmacodynamic interactions. The combination of these two structural fragments has proven to be a powerful tool for the discovery of new bioactive prototypes. This review consolidates advancements in the exploration of 4-quinolone-3-carboxamide derivatives, emphasizing their multifaceted biological activities and the innovative strategies driving their optimization. Key highlights include their potential as kinase inhibitors, antiviral agents, and anticancer therapeutics. By synthesizing insights from recent studies, this review underscores the relevance of this framework in addressing contemporary medicinal challenges.

Synthesis of LAVR-289, a new [(Z)-3-(acetoxymethyl)-4-(2,4-diaminopyrimidin-6-yl)oxy-but-2-enyl]phosphonic acid prodrug with pronounced antiviral activity against DNA viruses

New acyclic pyrimidine nucleoside phosphonate prodrugs with a 4-(2,4-diaminopyrimidin-6-yl)oxy-but-2-enyl]phosphonic acid skeleton (O-DAPy nucleobase) were prepared through a convergent synthesis by olefin cross-metathesis as the key step. Several acyclic nucleoside 4-(2,4-diaminopyrimidin-6-yl)oxy-but-2-enyl]phosphonic acid prodrug exhibited in vitro antiviral activity in submicromolar or nanomolar range against varicella zoster virus (VZV), human cytomegalovirus (HCMV), human herpes virus type 1 (HSV-1) and type 2 (HSV-2), and vaccinia virus (VV), with good selective index (SI). Among them, the analogue 9c (LAVR-289) proved markedly inhibitory against VZV wild-type (TK+) (EC50 0.0035 μM, SI 740) and for thymidine kinase VZV deficient strains (EC50 0.018 μM, SI 145), with a low morphological toxicity in cell culture at 100 μM and acceptable cytostatic activity resulting in excellent selectivity. Compound 9c exhibited antiviral activity against HCMV (EC50 0.021 μM) and VV (EC50 0.050 μM), as well as against HSV-1 (TK-) (EC50 0.0085 μM). Finally, LAVR-289 (9c) deserves further (pre)clinical investigations as a potent candidate broad-spectrum anti-herpesvirus drug.