The reactions of glyoxal with ammonia, ammonium salts, and amines cause the formation of the secondary organic aerosol (SOA) components (imidazole and its derivatives) in the atmosphere. The interaction of glyoxal and ammonia in aqueous solution is a primary reaction for these processes, and the explanation of its mechanism will allow developing the methods to control the formation of the SOA components. A detailed mechanism for the formation of key intermediates, namely, ethanediimine, diaminoethanediol, and aminoethanetriol, required for the imidazole ring cyclization, is proposed, and its potential energy surface (PES) has been constructed. This mechanism includes the experimentally identified intermediate compounds and takes into account the conformational and hydration equilibria of glyoxal. The schemes are proposed for further conversion of the key intermediates to the products of condensation between glyoxal and ammonia in the aqueous solution, C–N cyclic oligomers, that were identified. The products are shown to correspond to low positions on the PES in terms of Gibbs free energy, from −30.8 to −68.3 kcal mol⁻¹, which confirms the high probability of their formation. The preferable thermodynamic pathway for formation of the imidazole products does not comprise the conversion of the diimine intermediate with the participation of the proton, but rather the interaction of either the diaminoalcohol with glyoxal monohydrate or two monoamine derivatives between themeselves (aminoethantriol and aminohydroxyacetaldehyde).

The most thermodynamically and kinetically favorable pathways for the formation of 2-methylimidazole (2MI) in the reaction of glyoxal and acetaldehyde with ammonia in aqueous solution have been determined. The formation of 2MI proceeds through a number of successive intermediates of acyclic and cyclic structures, and the most favorable route (thermodynamically and kinetically) for the formation of the imidazole ring is the condensation of amine intermediates, in contrast to the existing concepts of imine structures. The limiting stage is the stage of cyclization involving the intramolecular attack by the amino group of the precyclic intermediate on the carbon atom bound to the hydroxyl group with the simultaneous release of a water molecule according to the S_N2 mechanism. Further stages of stepwise dehydration lead to the formation of a cyclic diazine, the intramolecular migration of the proton of the tertiary carbon atom to the nitrogen atom of which completes the formation of 2MI. Experimental studies on the effect of the order of mixing of initial reagents on the 2MI yield confirmed the quantum-chemically substantiated favorable pathway for the formation of 2MI during the interaction of amine intermediates, and also revealed that the selectivity of the 2MI formation is achieved by successive mixing of acetaldehyde with ammonia until the formation of hydroxyamine products and their further interaction with glyoxal.

For the first time, the two factors (the number of sites in the transition state and the nature of the catalytically active species) that affect the energy barriers ( E _a and Δ G ^‡ ) in atmospheric aldehyde reactions are proposed.

In situ formation of 2-methylimidazole as a result of 2,4,6-trimethyl-1,3,5-hexahydrotriazine trihydrate and glyoxal interaction in an aqueous solution is studied for the first time using NMR spectroscopy. In addition to the reactants and products, the reaction mixture is shown to contain stable intermediate products of the trimer decomposition as well as glycolic acid.

In the present work, the new N-methylol and O-alkyl derivatives of 4,5-dihydroxyimidazolidine-2-thione (DHIT) are synthesized. The effects of N-alkyl, N-phenyl, N-methylol, and O-alkyl substituents of DHIT on the ¹³C and ¹H signals in NMR spectra of the imidazolidine-2-thione ring are systematized using quantum chemical calculations. The shift values of carbon and hydrogen atoms are specific for the geometric isomers of the indicated DHIT derivatives. The chemical shifts of the carbon atoms of the methine groups allows for identifying the cis and trans isomers of the N-alkyl derivatives of DHIT due to the up-field shifts of the cis isomers. The introduction of an alkyl substituent at the N-position of the imidazolidine-2-thione ring leads to the up-field shifts of the carbon atoms of the ring due to the inductive effects of these groups. The ring current effect in the N-phenyl derivatives of DHIT that affects the positions of the carbon signals of the imidazolidine-2-thione ring has been found. The N-methylol derivatives of 4,5-dihydroxyimidazolidine-2-thione have been identified for the first time using 1D and 2D NMR.

Due to traumatic injuries, including those from surgical procedures, adhesions occur in over 50% of cases, necessitating exclusive surgical intervention for treatment. However, preventive measures can be implemented during abdominal organ surgeries. These measures involve creating a barrier around internal organs to forestall adhesion formation in the postoperative phase. Yet, the effectiveness of the artificial barrier relies on considerations of its biocompatibility and the avoidance of adverse effects on the body. This study explores the biocompatibility aspects, encompassing hemocompatibility, cytotoxicity, and antibacterial and antioxidant activities, as well as the adhesion of blood serum proteins and macrophages to the surface of new composite film materials. The materials, derived from the sodium salt of carboxymethylcellulose modified by glycoluril and allantoin, were investigated. The research reveals that film materials with a heterocyclic fragment exhibit biocompatibility comparable to commercially used samples in surgery. Notably, film samples developed with glycoluril outperform the effects of commercial samples in certain aspects.