Synthesis and biological properties of nitrobenzoxadiazole derivatives as potential nitrogen(ii) oxide donors: SOX induction, toxicity, genotoxicity, and DNA protective activity in experiments using Escherichia coli-based lux biosensors

Solubilizer of bacterial origin surfactin increases the biological activity of C60 fullerene

Currently, there exists conflicting data regarding the biological activity of unmodified fullerene C60. Various sources report its toxicity, geroprotective activity, and potential interaction with DNA. Contradictory findings regarding the toxicity of C60 may arise from the use of toxic solvents, as well as the influence of bioavailability and bioactivity on the preparation conditions of C60 suspensions. Furthermore, the microbiota of experimental animals can impact geroprotective activity results by releasing surfactants that facilitate substance penetration through the cell membrane. In this study, we selected conditions for solubilizing fullerene C60 in a solution of surfactin, a surfactant of bacterial origin, as well as in a 2% aqueous solution of TWEEN 80, employing ultrasound. Through bioluminescent analysis using lux biosensors in Escherichia coli MG1655, we observed that C60 in surfactin reduced induced genotoxic and oxidative stress. Given that surfactin enhances membrane permeability to fullerene C60, suspensions of fullerene in designated concentrations of surfactin can be regarded as a DNA protector and antioxidant, warranting further investigation as a promising component of novel drugs.

Design and Synthesis of New Boron-Based Benzo[c][1,2,5]oxadiazoles and Benzo[c][1,2,5]thiadiazoles as Potential Hypoxia Inhibitors

Benzo[c][1,2,5]oxadiazoles and benzo[c][1,2,5]thiadiazoles are recognized to possess potent pharmacological activities including anticancer potential. In continuation of our research endeavors in the development of boron-based heterocycles as potential therapeutic agents, herein we report the design and synthesis of new series of boron-based benzo[c][1,2,5]oxadiazoles and benzo[c][1,2,5]thiadiazoles as anticancer agents targeting tumor hypoxia. A series of seventeen compounds were synthesized in two steps in an efficient manner via substitution reactions followed by subsequent hydrolysis of aryltrifluoroboronate salts into corresponding boronic acid derivatives in the presence of silica. This is the first example to develop boron-based hypoxia agents. The synthesized hybrids were characterized by suitable spectroscopic techniques. The biological studies are currently underway.

Mechanisms of nitric oxide generation in living systems

In modern chemical and biochemical studies, special attention is paid to molecular systems capable of generating nitric oxide (NO), which is one of the most important signalling molecules in the body and can trigger a whole cascade of reactions. Despite the importance of this molecule, the mechanisms of its formation in living organisms remain a subject of debate. This review combines the most important methods of releasing NO from endogenous and exogenous sources. The history of endogenous NO donors dates back more than 150 years, since the synthesis of nitroglycerin, which remains the standard vasodilator today, even though it is known that it and many other similar compounds lead to the development of a nitrate tolerance. Particular awareness is devoted to the mechanisms of NO formation without the participation of enzymes, since these methods are most important for creating exogenous sources of NO as drugs. The study of NO formation methods is centred on both the creation of new NO donors and understanding the mechanisms of tolerance to them.

On the Nucleophilic Reactivity of 4,6-Dichloro-5-nitrobenzofuroxan with Some Aliphatic and Aromatic Amines: Selective Nucleophilic Substitution

The reaction rates for the nucleophilic aromatic substitution of 4,6-dichloro-5-nitrobenzofuroxan 1 with eight aliphatic amines (characterized by very different basicities/nucleophilicities) and three anilines have been measured in both methanol and toluene. The obtained rates have been related to the basicity (pK_aH in water and K_b in benzene) or nucleophilicity (N Mayr constants) of the tested amines. The whole of the obtained kinetic data has furnished useful information on the high nucleophilic reactivity of benzofuroxan derivatives, which has been related essentially to two factors: the high electron-drawing ability/power of the condensed furoxan ring and the low aromatic character of the benzofuroxan system.

Intriguing enigma of nitrobenzofuroxan's ‘Sphinx’: Boulton–Katritzky rearrangement or unusual evidence of the N-1/N-3-oxide rearrangement?

The first attempt to compare Boulton–Katritzky rearrangement with N-1/N-3-oxide tautomerism: formation of isomeric products in the reaction between 2-aminothiazoles and 7-chloro-4,6-dinitrobenzofuroxan.