Synthesis, anticancer activity, and SAR analyses of compounds containing the 5:7-fused 4,6,8-triaminoimidazo[4,5-e][1,3]diazepine ring system

Unveiling the Origin of the Selectivity and the Molecular Mechanism in the [3+2] Cycloaddition Reaction of N-aryl-C-carbamoylnitrone with N-arylitaconimide

The [3+2] cycloaddition reaction of N-aryl-C-carbamoylnitrone (nitrone 1) with N-arylitaconimide (ethylene 2) was computationally studied using the B3LYP/6-31G(d) level of theory. An analysis of the different energetic profiles and the transition states’ optimized structures clearly indicated that this 32CA occurred through a non-polar, asynchronous, one-step mechanism, favoring the formation of the ortho–endo cycloadduct, as observed experimentally. The analysis of the reactivity indices derived from the conceptual DFT explains well the low polarity of this 32CA reaction. Parr functions and a dual reactivity descriptors analysis correctly explained the regioselectivity ortho of this 32CA reaction. Solvent effects did not modify the obtained selectivity but it increased the activation energies and decreased the exothermic character of this 32CA reaction. A thermodynamic parameters analysis indicated that this 32CA wascharacterized by an ortho regioselectivity and endostereoselectivity and exothermic and exergonic characters.

DEAD-Box Helicase DDX3X as a Host Target against Emerging Viruses: New Insights for Medicinal Chemical Approaches

In recent years, globalization, global warming, and population aging have contributed to the spread of emerging viruses, such as coronaviruses (COVs), West Nile (WNV), Dengue (DENV), and Zika (ZIKV). The number of reported infections is increasing, and considering the high viral mutation rate, it is conceivable that it will increase significantly in the coming years. The risk caused by viruses is now more evident due to the COVID-19 pandemic, which highlighted the need to find new broad-spectrum antiviral agents able to tackle the present pandemic and future epidemics. DDX3X helicase is a host factor required for viral replication. Selective inhibitors have been identified and developed into broad-spectrum antivirals active against emerging pathogens, including SARS-CoV-2 and most importantly against drug-resistant strains. This perspective describes the inhibitors identified in the last years, highlighting their therapeutic potential as innovative broad-spectrum antivirals.

1,3-Diazepine: A privileged scaffold in medicinal chemistry

Privileged structures have been widely used as effective templates for drug discovery. While benzo-1,4-diazepine constitutes the first historical example of such a structure, the 1,3 analogue is just as rich in terms of applications in medicinal chemistry. The 1,3-diazepine moiety is present in numerous biological active compounds including natural products, and is used to design compounds displaying a large range of biological activities. It is present in the clinically used anticancer compound pentostatin, in several recent FDA approved β-lactamase inhibitors (e.g., avibactam) and also in coformycin, a natural product known as a ring-expanded purine analogue displaying antiviral and anticancer activities. Several other 1,3-diazepine containing compounds have entered into clinical trials. This heterocyclic structure has been and is still widely used in medicinal chemistry to design enzyme inhibitors, GPCR ligands, and so forth. This review endeavours to highlight the main use of the 1,3-diazepine scaffold and its derivatives, and their applications in medicinal chemistry, drug design, and therapy. We will focus more particularly on the development of enzyme inhibitors incorporating this scaffold, with a strong emphasis on the molecular interactions involved in the inhibition mechanism.

Rh-Catalyzed C-H activation/intramolecular condensation for the construction of benzo[f]pyrazolo[1,5-a][1,3]diazepines

A novel and mild Rh(iii)-catalyzed C-H activation/intramolecular condensation of 1-aryl-1H-pyrazol-5-amines with cyclic 2-diazo-1,3-diketones was developed, giving access to various important benzo[f]pyrazolo[1,5-a][1,3]diazepine scaffolds through sequential C-C/C-N bond formation in a one-pot procedure under additive- and oxidant-free conditions. Furthermore, 3-([1,1'-biphenyl]-2-ylamino)-2-ethoxycyclohex-2-enones can be obtained in good yields by constructing C-O and C-N bonds through 1,1'-insertion, dehydration, and isomerization processes.

2,4-Disubstituted Quinazoline Derivatives Act as Inducers of Tubulin Polymerization: Synthesis and Cytotoxicity

BACKGROUND

During last recent years number of anti-tubulin agents were introduced for treatment of diverse kind of cancer. Despite of their potential in treatment of cancer, drug resistance and adverse toxicity such as peripheral neuropathy are some of the negative criteria of anti-tubulin agents.

METHODS

Twenty seven quinazoline derivatives were synthesized using a multicomponent reaction. The cytotoxicity of compounds 1-27 was tested in SRB assays employing five different human tumor cell lines. Effect of two of active compounds on tubulin polymerization was also checked using a commercially available assay kit. Molecular modelling studies were also performed using autodock tools software.

RESULTS

SRB assays showed that compounds 2, 9, 16 and 26, being highly cytotoxic with IC50 values ranging between 2.1 and 14.3µM. The possible mode of action of compounds, 2, 9, 16 and 26, and the taxol binding site of the protein tubulin, an important goal for antimitotic drugs, was also studied by molecular docking, which showed reasonable interactions with tubulin active site, followed by investigation of the effects of compounds 9 and 16 on the polymerization of tubulin. The results showed the tested compounds to be highly active as inducers of tubulin polymerization.

CONCLUSION

Altogether, with respect to obtained results, it is attractive and beneficial to further investigation on quinazoline scaffold as antimitotic agents.

Synthesis of N-Pyrrolyl(furanyl)-Substituted Piperazines, 1,4-Dizepanes, and 1,4-Diazocanes

The synthetic potential of 5-bromo-1,1,1-trifluoro-4-methoxypent-3-en-2-one toward the catalyst-free synthesis of N-pyrrolyl(furanyl)-piperazines, 1,4-diazepanes, and 1,4-diazocanes through a telescoped protocol is reported. This three-component one-pot method provided 23 examples with high chemo- and regioselectivity at yields up to 96%.

Design, Synthesis and Anticancer Evaluation of Novel Series of Indibulin Analogues

Background:

Cancer is an important cause of human death worldwide. During the last decades, many anticancer agents with anti-tubulin mechanism have been synthesized or extracted from nature and some of them also entered clinical use. Indibulin is one of the most potent tubulin polymerization inhibitors with minimal peripheral neuropathy, which is a big problem by some of the antimitotic agents such as taxanes and vinka alkaloids. With respect to this giant benefit, herein we decided to design and synthesize novel indibulin related compounds and investigate their anticancer activity against HT-29, Caco-2 and T47-D cancerous cell lines as well as NIH-T3T as normal cell line.

Objective:

The aim of this study was to synthesize new anti-cancer agents and evaluates their cytotoxic activity on diverse cancerous and normal cell lines.

Method:

Target compounds were synthesized in multistep reaction and cytotoxic activity was investigated by MTT cell viability assay.

Results:

Herein, nine novel target compounds were synthesized in moderate to good yield. Some of the compounds exerted good cytotoxic activity against cancerous cell lines. Annexin V/PI staining showed that compound 4g could induce apoptosis and necrosis in HT-29 cell line.

Conclusion:

It is valuable to do further investigation on compound 4g which showed the highest activity against HT-29 and Caco-2 (IC50 values are 6.9 and 7 &µM respectively). Also, synthesis of new derivatives of current synthesized compounds is suggested.

Synthesis of Tetracyclic 2,3-Dihydro-1,3-diazepines from a Dinitrodibenzothiophene Derivative

Triply fused 1,3-diazepine derivatives have been obtained by acidic reduction of rotationally locked and sterically hindered nitro groups in the presence of an aldehyde or ketone. The nitro groups are sited on adjacent rings of a dicyanodibenzothiophene-5,5-dioxide, which also displays fully reversible two-electron-accepting behavior. The synthesis, crystallographically determined molecular structures, and aspects of the electronic properties of these new molecules are presented.

Design, synthesis and cytotoxicity evaluation of indibulin analogs

Indibulin is one of the most potent tubulin polymerization inhibitors with minimal peripheral neuropathy. The design and synthesis of new indibulin analogs were carried out in order to investigate their anti-cancer activity. The target compounds 4a–i were synthesized in multistep reactions starting with the related indole derivatives. Compound 4f shows the highest cytotoxic activity on HT-29 and Caco-2 cell lines with the respective half maximal inhibitory concentration (IC50) values of 5.1 μm and 7.3 μm. In the case of the T47-D cell line, compound 4c exerts the best cytotoxic activity with an IC50 value of 11.5 μm. In the cell cycle analysis on HT-29 cells, compound 4f at 5.1 μm showed an increase in the percentage of cells in the sub-G1 phase. Altogether, nine target compounds were synthesized and characterized by infrared spectroscopy (IR), proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR), mass spectrometry (MS) and elemental analysis. Some of the compounds show good cytotoxic activity against cancerous cell lines.

Synthesis of unprecedented steroidal spiro heterocycles as potential antiproliferative drugs

Herein we report the straightforward preparation of novel conformationally-restricted steroids from trans-androsterone and estrone, decorated with spiranic oxazolidin-2-one or 2-aminooxazoline motifs at C-17 as potential antiproliferative agents. Such unprecedented pharmacophores were accessed using an aminomethylalcohol derivative at C-17 as the key intermediate; reaction of such functionality with triphosgene, or conversion into N-substituted thioureas, followed by an intramolecular cyclodesulfurization reaction promoted by yellow HgO, furnished such spirocycles in excellent yields. Title compounds were tested in vitro against a panel of six human tumor cell lines, named A549 (non-small cell lung), HBL-100 (breast), HeLa (cervix), SW1573 (non-small cell lung), T-47D (breast) and WiDr (colon), and the results were compared with steroidal chemotherapeutic agents (abiraterone and galeterone); the A-ring of the steroidal backbone, the nature of the heterocycle and the N-substituents proved to be essential motifs for establishing structure-activity relationships concerning not only the potency but also the selectivity against tumor cell lines. Estrone derivatives, particularly those bearing a spiranic 2-aminooxazoline scaffold were found to be the most active compounds, with GI₅₀ values ranging from the low micromolar to the submicromolar level (0.34-1.5 μM). Noteworthy, the lead compounds showed a remarkable increase in activity against the resistant cancer cell lines (T-47D and WiDr) compared to the anticancer reference drugs (up to 120-fold).