Benzofuroxans: their synthesis, properties, and biological activity

Tuning Green Explosives through SNAr Chemistry

Reactivity and regioselectivity of SNAr-type fluorine substitution with azide in polyfluorosubstituted nitrobenzenes was studied both theoretically and experimentally. The obtained polyazido-substituted nitrobenzene derivatives were extensively characterized by NMR, IR, HPLC, X-ray, and DFT methods. It was found that the substitution with the azide nucleophile occurs first at the para- and the ortho-positions to the NO2-group and that transazidation reactions also occur here. Thermal decomposition of prepared azidonitrobenzenes was studied both in controlled (kinetic decay) and uncontrolled (explosion) modes. In case of the controlled thermal decomposition of ortho-azidonitrobenzenes, benzofuroxans were found as major products of the reaction unless another azido group was adjacent to the furoxan moiety. The bursting power of azidonitrobenzenes was found to rise gradually with the number of the azide substituents in the aromatic ring.

Diverse Biological Activity of Benzofuroxan/Sterically Hindered Phenols Hybrids

Combining two pharmacophores in a molecule can lead to useful synergistic effects. Herein, we show hybrid systems that combine sterically hindered phenols with dinitrobenzofuroxan fragments exhibit a broad range of biological activities. The modular assembly of such phenol/benzofuroxan hybrids allows variations in the phenol/benzofuroxan ratio. Interestingly, the antimicrobial activity only appears when at least two benzofuroxan moieties are introduced per phenol. The most potent of the synthesized compounds exhibit high cytotoxicity against human duodenal adenocarcinoma (HuTu 80), human breast adenocarcinoma (MCF-7), and human cervical carcinoma cell lines. This toxicity is associated with the induction of apoptosis via the internal mitochondrial pathway and an increase in ROS production. Encouragingly, the index of selectivity relative to healthy tissues exceeds that for the reference drugs Doxorubicin and Sorafenib. The biostability of the leading compounds in whole mice blood is sufficiently high for their future quantification in biological matrices.

Water-Soluble Salts Based on Benzofuroxan Derivatives-Synthesis and Biological Activity

A series of novel water-soluble salts of benzofuroxans was achieved via aromatic nucleophilic substitution reaction of 4,6-dichloro-5-nitrobenzofuroxan with various amines. The salts obtained showed good effectiveness of the pre-sowing treatment of seeds of agricultural crops at concentrations of 20-40 mmol. In some cases, the seed treatment with salts leads not only to improved seed germination, but also to the suppression of microflora growth. Additionally, their anti-cancer activityin vitrohas been researched. The compounds with morpholine fragments or a fragment of N-dimethylpropylamine, demonstrated the highest cytotoxic activity, which is in good correlation with the ability to inhibit the glycolysis process in tumor cells. Two compounds 4e and 4g were selected for further experiments using laboratory animals. It was found that the lethal dose of 50% (LD₅₀) is 22.0 ± 1.33 mg/kg for 4e and 13.75 ± 1.73 mg/kg for 4g, i.e., compound 4e is two times less toxic than 4g, according to the mouse model in vivo. It was shown that the studied compounds exhibit antileukemia activity after a single intraperitoneal injection at doses from 1.25 to 5 mg/kg, as a result of which the average lifespan of animals with a P388 murine leukemia tumor increases from 20 to 28%. Thus, the water-soluble salts of benzofuroxans can be considered as promisingcandidates for further development, both as anti-cancer agents and as stimulants for seed germination and regulators of microflora crop growth.

Synthesis and antiproliferative activity characterization of new imidazothiazolotriazine oxindolylidene derivatives containing various substituents in the oxindole ring

Condensation of 1,3-diethyltetrahydroimidazo[4,5-е]thiazolo[3,2-b][1,2,4]triazine-2,7-dione with isatins followed by framework rearrangement in the thiazolotriazine moiety was used to synthesize two new series of oxindolylidenetetrahydroimidazo[4,5-е]thiazolo- [3,2-b][1,2,4]triazine-2,7-diones and oxindolylidenetetrahydroimidazo[4,5-е]thiazolo[2,3-c][1,2,4]triazine-2,8-diones containing various substituents in the oxindole moiety. The obtained compounds were tested for antiproliferative activity. The greatest activity was observed in the case of 1-alkyl-7-methyloxindolylidene derivatives of imidazo[4,5-е]thiazolo[2,3-c]triazine, which not only inhibited the growth of more than half of the studied cell lines, but also caused cell death in the SF-539 cell line (central nervous system cancer, mean growth percent –7.82%) and MDA-MB-435 (melanoma, –30.97 and –13.64%).

Biosourced Vanillin-Based Building Blocks for Organic Electronic Materials

Forest biomass is viewed as a significant source of organic carbon and thus the ideal replacement of petroleum products. From the resources derived from biomass, lignocellulose is the most abundant biobased material on earth. One of the aromatic added value compounds obtained from the depolymerization of lignin is vanillin. Here, we report the preparation of new compounds having benzothiophene, indole, isatin, benzofuroxan, benzofurazan, benzothiadiazole, and phthalimide heteroaromatic ring structures. More precisely, our results show that vanillin can be used as a biosourced starting material for the preparation of a variety of aromatic dibrominated monomers. X-ray crystallography on single crystals was also performed to obtain meaningful information on their solid-state ordering. This work opens the way to new, sustainable, biosourced aromatic materials (small molecules or polymers) for organic electronics.

Synthesis of 7-amino-6-halogeno-3-phenylquinoxaline-2-carbonitrile 1,4-dioxides: a way forward for targeting hypoxia and drug resistance of cancer cells

New water-soluble hypoxia activated 7-aminoquinoxaline 1,4-dioxides, prepared by the regioselective Beirut reaction, acted as HIF-1α suppressors and induced apoptosis in hypoxic and MDR cancer cells.