One-pot Sonogashira-cyclization protocol to obtain substituted furopyrimidine nucleosides in aqueous conditions

Discovery of novel furo[2,3-d]pyrimidin-2-one-1,3,4-oxadiazole hybrid derivatives as dual antiviral and anticancer agents that induce apoptosis

A new series of furo[2,3-d]pyrimidine-1,3,4-oxadiazole hybrid derivatives were synthesized via an environmentally friendly, multistep synthetic tool and a one-pot Songoashira-heterocyclization protocol using, for the first time, nanostructured palladium pyrophosphate (Na₂ PdP₂ O₇ ) as a heterogeneous catalyst. Compounds 9a-c exhibited broad-spectrum activity with low micromolar EC₅₀ values toward wild and mutant varicella-zoster virus (VZV) strains. Compound 9b was up to threefold more potent than the reference drug acyclovir against thymidine kinase-deficient VZV strains. Importantly, derivative 9b was not cytostatic at the maximum tested concentration (CC₅₀  > 100 µM) and had an acceptable selectivity index value of up to 7.8. Moreover, all synthesized 1,3,4-oxadiazole hybrids were evaluated for their cytotoxic activity in four human cancer cell lines: fibrosarcoma (HT-1080), breast (MCF-7 and MDA-MB-231), and lung carcinoma (A549). Data showed that compound 8f exhibits moderate cytotoxicity, with IC₅₀ values ranging from 13.89 to 19.43 µM. Besides, compound 8f induced apoptosis through caspase 3/7 activation, cell death independently of the mitochondrial pathway, and cell cycle arrest in the S phase for HT1080 cells and the G1/M phase for A549 cells. Finally, the molecular docking study confirmed that the anticancer activity of the synthesized compounds is mediated by the activation of caspase 3.

Eucalyptol: A Bio-Based Solvent for the Synthesis of O,S,N-Heterocycles. Application to Hiyama Coupling, Cyanation, and Multicomponent Reactions

We report here the use of eucalyptol as a bio-based solvent for Hiyama coupling, cyanation, and multicomponent reactions on O,S,N-heterocycles. These heterocycles were chosen as targets or as starting materials given their biological potential; they play an important role in therapeutically active compounds. Once again, eucalyptol proved to be a credible and sustainable alternative to common solvents.

Laser synthesis: a solvent-free approach for the preparation of phenylthiazolo[5,4-b]pyridine derivatives

We describe here a rapid and straightforward solvent-free method to access phenylthiazolo[5,4-b]pyridines using a Nd-YAG laser NANO-NY81-10 (λ = 355 nm, 10 Hz pulse frequency; 8 ns pulse duration).

Eucalyptol as a Bio-Based Solvent for Buchwald-Hartwig Reaction on O,S,N-Heterocycles

We report here the use of eucalyptol as a bio-based solvent for the Buchwald–Hartwig reaction on O,S,N-heterocycles. These heterocycles containing oxygen, sulfur and nitrogen were chosen as targets or as starting materials. Once again, eucalyptol demonstrated to be a possible sustainable alternative to common solvents.

Hetero-bimetallic cooperative catalysis for the synthesis of heteroarenes

Review covering the synthesis of 5- and 6-membered as well as condensed heteroarenes, focussing on the combinations in cooperative catalytic systems in strategies used to achieve selectivity and also highlights the mode of action for the cooperative catalysis leading to the synthesis of commercially and biologically relevant heteroarenes.

A Greener and Efficient Method for Nucleophilic Aromatic Substitution of Nitrogen-Containing Fused Heterocycles

A simple and efficient methodology for the nucleophilic aromatic substitution of nitrogen-containing fused heterocycles with interesting biological activities has been developed in an environmentally sound manner using polyethylene glycol (PEG-400) as the solvent, leading to the expected compounds in excellent yields in only five minutes.

Novel pyrimidine-2,4-dione-1,2,3-triazole and furo[2,3-d]pyrimidine-2-one-1,2,3-triazole hybrids as potential anti-cancer agents: Synthesis, computational and X-ray analysis and biological evaluation

Regioselective 1,4-disubstituted 1,2,3-triazole tethered pyrimidine-2,4-dione derivatives (5-23) were successfully prepared by the copper(I)-catalyzed click chemistry. While known palladium/copper-cocatalyzed method based on Sonogashira cross-coupling followed by the intramolecular 5-endo-dig ring closure generated novel 6-alkylfuro[2,3-d]pyrimidine-2-one-1,2,3-triazole hybrids (24b-37b), a small library of their 5-alkylethynyl analogs (24a-37a) was synthesized and described for the first time by tandem terminal alkyne dimerization and subsequent 5-endo-trig cyclization, which was additionally corroborated with computational and X-ray crystal structure analyses. The nature of substituents on alkynes and thereof homocoupled 1,3-diynes predominantly influenced the ratio of the formed products in both pathways. In vitro antiproliferative activity of prepared compounds evaluated on five human cancer cell lines revealed that N,N-1,3-bis-(1,2,3-triazole)-5-bromouracil (5-7) and 5,6-disubstituted furo[2,3-d]pyrimidine-2-one-1,2,3-triazole 34a hybrids exhibited the most pronounced cytostatic acitivities against hepatocellular carcinoma (HepG2) and cervical carcinoma (HeLa) cells with higher potencies than the reference drug 5-fluorouracil. Cytostatic effect of pyrimidine-2,4-dione-1,2,3-triazole hybrid 7 in HepG2 cells could be attributed to the Wee-1 kinase inhibition and abolishment of sphingolipid signaling mediated by acid ceramidase and sphingosine kinase 1. Importantly, this compound proved to be a non-mitochondrial toxicant, which makes it a promising candidate for further lead optimization and development of a new and more efficient agent for the treatment of hepatocellular carcinoma.

Novel water-soluble phosphatriazenes: versatile ligands for Suzuki–Miyaura, Sonogashira and Heck reactions of nucleosides

Two new water-soluble phosphatriazene as versatile ligands for catalyzing Suzuki–Miyaura reactions of purines and pyrimidines in neat water with the possibility of recycling. Copper-free Sonogashira and Heck reaction were also made possible.

Efficient synthesis of unprotected C-5-aryl/heteroaryl-2'-deoxyuridine via a Suzuki-Miyaura reaction in aqueous media

Following our previous results on an environmentally benign one-pot Sonogashira-cyclization protocol to obtain substituted furopyrimidine nucleosides under aqueous conditions, we investigate herein the Suzuki-Miyaura cross-coupling reactions of aryl and heteroaryl derivatives at the C5 position of unprotected 2'-deoxyuridine in the same media with a common catalyst system avoiding exotic ligands, since palladium acetate and triphenylphosphine afforded the expected products in moderate to good yields.