Synthesis and antitumor activity of novel 2',3'-diethanethio-2',3',5'-trideoxy-5'-triazolonucleoside analogues

Novel 3'-[4-fluoroaryl-(1,2,3-triazol-1-yl)]-3'-deoxythymidine analogues: Design, synthesis, characterization and their potential as anticancer agents

Novel 3'-[4-fluoroaryl-(1,2,3-triazol-1-yl)]-3'-deoxythymidine analogues (7a-l) were developed by the Cu alkyne-azide cycloaddition (CuAAC) reaction. The obtained lead compounds were confirmed by using ¹H NMR, ¹³C NMR, 2 D NMR, HRMS and their anticancer activities were screened against Huh-7 liver cancer cells and U87MG human glioblastoma cells. Among the synthesized fluorinated 1,2,3-triazolyl nucleosides, three compounds (7i, 7a-b) demonstrated promising anti-proliferative against Huh-7 and U87MG cell lines. Significantly, compound 7i has displayed remarkable promising anticancer activity with IC₅₀ value in the micromole range (22.41-24.92 µM) and (18.12-21.36 µM) against Huh-7 cancer cells and U87MG glioblastoma cells, respectively.

Green synthesis of triazolo-nucleoside conjugates via azide–alkyne C–N bond formation

Modified nucleosides are the core precursors for the synthesis of artificial nucleic acids, and are important in the field of synthetic and medicinal chemistry. In order to synthesize various triazolo-compounds, copper and ruthenium catalysed azide–alkyne 1,3-dipolar cycloaddition reactions also known as click reaction have emerged as a facile and efficient tool due to its simplicity and convenient conditions. Introduction of a triazole ring in nucleosides enhances their therapeutic value and various photophysical properties. This review primarily focuses on the plethora of synthetic methodologies being employed to synthesize sugar modified triazolyl nucleosides, their therapeutic importance and various other applications.

Developments in the Application of 1,2,3-Triazoles in Cancer Treatment

BACKGROUND

The impact of cancer on modern society cannot be emphasized enough in terms of both economic and human costs. Cancer treatments are known, unfortunately, for their side effects - frequently numerous and severe. Drug resistance is another issue medical professionals have to tackle when dealing with neoplastic illnesses. Cancer rates are rising worldwide due to various factors - low-quality nutrition, air and water pollution, tobacco use, etc. For those and many other reasons, drug discovery in the field of oncology is a top priority in modern medical science.

OBJECTIVE

To present the reader with the latest in cancer drug discovery with regard to 1,2,3-triazole- containing molecules in a clear, concise way so as to make the present review a useful tool for researchers.

METHODS

Available information present on the role of 1,2,3-triazoles in cancer treatment was collected. Data was collected from scientific literature, as well as from patents.

RESULTS

A vast number of triazole-containing molecules with antiproliferative properties have been proposed, synthesized and tested for anticancer activity both in vitro and in vivo. The substances vary greatly when considering molecular structure, proposed mechanisms of action and affected cancer cell types.

CONCLUSION

Triazole-containing molecules with anticancer activity are being widely synthesized and extensively tested. They vary significantly in terms of both structure and mechanism of action. The methods for their preparation and administration are well established and with proven reproducibility. These facts suggest that triazoles may play an important role in the discovery of novel antiproliferative medications with improved effectiveness and safety profile.

Advance of structural modification of nucleosides scaffold

With Remdesivir being approved by FDA as a drug for the treatment of Corona Virus Disease 2019 (COVID-19), nucleoside drugs have once again received widespread attention in the medical community. Herein, we summarized modification of traditional nucleoside framework (sugar + base), traizole nucleosides, nucleoside analogues assembled by other drugs, macromolecule-modified nucleosides, and their bioactivity rules. 2'-"Ara"-substituted by -F or -CN group, and 3'-"ara" substituted by acetylenyl group can greatly influence their anti-tumor activities. Dideoxy dehydrogenation of 2',3'-sites can enhance antiviral efficiencies. Acyclic nucleosides and L-type nucleosides mainly represented antiviral capabilities. 5-F Substituted uracil analogues exihibit anti-tumor effects, and the substrates substituted by -I, -CF3, bromovinyl group usually show antiviral activities. The sugar coupled with 1-N of triazolid usually displays anti-tumor efficiencies, while the sugar coupled with 2-N of triazolid mainly represents antiviral activities. The nucleoside analogues assembled by cholesterol, polyethylene glycol, fatty acid and phospholipid would improve their bioavailabilities and bioactivities, or reduce their toxicities.

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.

In search of uracil derivatives as bioactive agents. Uracils and fused uracils: Synthesis, biological activity and applications

This review article is an effort to summarize recent developments in researches providing uracil derivatives with promising biological potential. This article also aims to discuss potential future directions on the development of more potent and specific uracil analogues for various biological targets. Uracils are considered as privileged structures in drug discovery with a wide array of biological activities and synthetic accessibility. Antiviral and anti-tumour are the two most widely reported activities of uracil analogues however they also possess herbicidal, insecticidal and bactericidal activities. Their antiviral potential is based on the inhibition of key step in viral replication pathway resulting in potent activities against HIV, hepatitis B and C, the herpes viruses etc. Uracil derivatives such as 5-fluorouracil or 5-chlorouracil were the first pharmacological active derivatives to be generated. Poor selectivity limits its therapeutic application, resulting in high incidences of gastrointestinal tract or central nervous toxicity. Numerous modifications of uracil structure have been performed to tackle these problems resulting in the development of derivatives exhibiting better pharmacological and pharmacokinetic properties including increased bioactivity, selectivity, metabolic stability, absorption and lower toxicity. Researches of new uracils and fused uracil derivatives as bioactive agents are related with modifications of substituents at N(1), N(3), C(5) and C(6) positions of pyrimidine ring. This review is an endeavour to highlight the progress in the chemistry and biological activity of the uracils, predominately after the year 2000. In particular are presented synthetic methods and biological study for such analogues as: 5-fluorouracil or 5-chlorouracil derivatives, tegafur analogues, arabinopyranonucleosides of uracil, glucopyranonucleosides of uracil, liposidomycins, caprazamycins or tunicamycins, tritylated uridine analogues, nitro or cyano derivatives of uracil, uracil-quinazolinone, uracil-indole or uracil-isatin-conjugates, pyrimidinophanes containing one or two uracil units and nitrogen atoms in bridging polymethylene chains etc. In this review is also discussed synthesis and biological activity of fused uracils having uracil ring annulated with other heterocyclic ring.

Chemical architecture and applications of nucleic acid derivatives containing 1,2,3-triazole functionalities synthesized via click chemistry

There is considerable attention directed at chemically modifying nucleic acids with robust functional groups in order to alter their properties. Since the breakthrough of copper-assisted azide-alkyne cycloadditions (CuAAC), there have been several reports describing the synthesis and properties of novel triazole-modified nucleic acid derivatives for potential downstream DNA- and RNA-based applications. This review will focus on highlighting representative novel nucleic acid molecular structures that have been synthesized via the “click” azide-alkyne cycloaddition. Many of these derivatives show compatibility for various applications that involve enzymatic transformation, nucleic acid hybridization, molecular tagging and purification, and gene silencing. The details of these applications are discussed. In conclusion, the future of nucleic acid analogues functionalized with triazoles is promising.

Design, synthesis, antiviral and cytostatic evaluation of novel isoxazolidine nucleotide analogues with a 1,2,3-triazole linker

Azidation (TMSN(3), SnCl(4)) of a 9:1 mixture of trans- and cis-5-acetoxy-2-methylisoxazolidin-3-yl-3-phosphonates at the anomeric carbon atom led to the formation of the equimolar mixture of cis- and trans-5-azido-2-methylisoxazolidin-3-yl-3-phosphonates, which were efficiently separated. The 1,3-dipolar cycloaddition of pure trans- and cis-5-azidoisoxazolidin-3-yl-3-phosphonates with selected alkynes gave the respective nucleoside mimetics containing a 1,2,3-triazole linker. The (1,2,3-triazolyl)isoxazolidine phosphonates obtained herein were evaluated in vitro for activity against a variety of DNA and RNA viruses. None of the compounds were endowed with antiviral activity at subtoxic concentrations. Compounds 15f-j and 16f-j were cytostatic in the higher micromolar range.

Synthesis of new C5-(1-substituted-1,2,3-triazol-4 or 5-yl)-2'-deoxyuridines and their antiviral evaluation

The synthesis and antiviral evaluation of a series of C5-(1,4- and 1,5-disubstituted-1,2,3-triazolo)-nucleoside derivatives is described. The key steps of this synthesis are regioselective Huisgen's 1,3-dipolar cycloaddition, using either copper-catalyzed azide-alkyne cycloaddition (CuAAC) or ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) under microwave activation. Some compounds among the 5a-l series possess activity against herpes simplex viruses 1 and 2, varicella-zoster virus, human cytomegalovirus and vaccinia virus. Their cytostatic activities were determined against murine leukemia cells, human T-lymphocyte cells and cervix carcinoma cells. Compounds were also evaluated on a wide panel of RNA viruses, including Vesicular stomatitis virus, influenza viruses type A (H1N1 and H3N2) and B in MDCK cell cultures, parainfluenza-3 virus, reovirus-1, Sindbis virus and Punta Toro virus in Vero cell cultures and Vesicular stomatitis, Coxsackie B4 and respiratory syncytial virus, with no specific antiviral effect.