Химия

Stable nitroxyl radicals, such as TEMPONE, are widely used in organic synthesis and ESR spectroscopy. Traditional methods for their preparation from secondary amines often require transition metal catalysts, harsh conditions, or aggressive reagents, leading to side reactions. Therefore, fi nding novel, more selective oxidative systems remains a highly relevant task. This study proposes a new non-catalytic method for synthesizing the TEMPONE radical via direct oxidation of 2,2,6,6-tetramethylpiperidin-4-one using cyclohexylidene-1,1-bis(hydroperoxide).

The antiradical activity of extractive gallotannins isolated from the leaves of the common smoke tree (Cotinus coggygria Scop.), as well as their synergistic eff ects in binary mixtures with low-molecular-weight phenolic acids and their methoxy derivatives have been investigated. The antiradical activity of the compounds has been evaluated by the initial rate of reaction with 2,2’-diphenyl-1-picrylhydrazyl in dimethyl sulfoxide at 298±2 K using photocolorimetry.

A new approach to the diagnosis of irreversible transformations in dispersed media has been developed based on the analysis of the lability of their electrochemical parameters when exposed to direct current. Unlike traditional methods that analyze equilibrium states, this technique uses the characteristics of nonequilibrium processes. Studies on model objects (oil shales, pHospHogypsum, and sandy-clay rocks) have revealed diagnostic criteria for lability, including kinetic, structural-resistive, and pHase parameters.

Folic acid (FA) is an essential vitamin; however, when exposed to ultraviolet (UV) radiation, it undergoes photodegradation to form fl uorescent products, specifically 6-carboxypterin and 6-formylpterin. These compounds belong to the class of pterins, which can act as endogenous photosensitizers and accumulate in the skin in certain pathologies. The interaction of these photoproducts with proteins, particularly serum albumin, the main transport protein of blood plasma and interstitial fl uid, determines their biodistribution and photosensitizing activity.

Statins, key drugs for the prevention of cardiovascular disease, are represented by a number of structurally diverse compounds requiring reliable identifi cation methods to ensure their quality control. This study, for the fi rst time, provides a comprehensive comparative analysis of all commercially signifi cant statins (lovastatin, simvastatin, pravastatin, fl uvastatin, atorvastatin, rosuvastatin, and pitavastatin) using complementary spectral methods: UV, FTIR (ATR), ¹H NMR spectroscopy, and mass spectrometry.

Gold nanoparticles (AuNPs) have been created utilizing pomegranate (Punica granatum L.) peel extract as a natural reducing and stabilizing agent in an environmentally friendly green synthesis method. Pomegranate peel contains polyphenols and antioxidant phytochemicals that effi ciently convert hydrogen tetrachloroaurate (HAuCl4) to generate stable AuNPs, as indicated by a distinctive color change from light yellow to wine red and validated using UVVis spectroscopy.