quaternary ammonium salts
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The critical micelle concentration (CMC) of the selected surfactant belonging to quaternary ammonium salts with chemical designation N,N-dimethyl-N-(3-((1R,5S)-1,8,8-trimethyl-2,4-dioxo-3-azabicyclo[3.2.1]octane-3yl)propyl)hexadecane-1-amine bromide was determined. Simultaneously, the effect of the addition of various concentrations of NaCl, KCl, NaBr, and KBr salts on the CMC value of the substance was observed and compared with those obtained in an aqueous solution at T = 296,15 K. Based on the results obtained, it was concluded that NaCl and KCl salts decreased the critical micelle concentration, while NaBr and KBr salts did not support micellization and CMC values therefore increased. In the case of solutions of a substance in the salt environment, when compared to the substance's solution in distilled water, a decrease in partial molar volume was observed. From the concentration density dependencies of the substance, an ionization degree of α was determined. Finally, the molar Gibbs energy ∆G° was also calculated and found negative for all salt solutions, while increase with their increasing concentration.

In this protocol, hybridization is first performed in conventional aqueous solvents at a temperature well below the melting temperature, and the hybrids are then washed at higher stringency in buffers containing quaternary alkylammonium salts. TMACl is used with probes that are 14–50 nt in length, whereas TEACl is used with oligonucleotides that are 50–200 nt in length.

Aim. To generalize and systematize information on the properties of modern chemical disinfectants and antiseptic agents (DA and AA) – peroxide compounds, surfactants, salts of heavy metals and metals of variable valence in the highest oxidation state, alcohols, phenols and quaternary ammonium salts.Results and discussion. The classification of DA and AA by the chemical structure was performed. The spectrum of their activity, directions and forms of DA and AA were given. Toxicity and the impact on the environment were described.Conclusions. The results of the study conducted allow us to state that modern DA and AA of a wide spectrum of action are peracetic acid and, to a certain extent, hydrogen peroxide. However, they are unstable in dilute solutions. Other reagents are chemically stable, but they are characterized by a weak or average action against spores and viruses. The most effective DA and AA are mixtures (combinations) of compounds belonging to different classes. The examples of these combinations are “surfactants + biguanidine derivatives”; “quaternary ammonium salts + phenol derivatives”; “surfactants + aldehydes”; “quaternary ammonium salts + hydrogen peroxide”. These mixtures combine the advantages and compensate for the disadvantages of individual DA and AA.

A series of mono- or bis-quaternary ammonium salts derived from cinchonidine or quinine was synthesized and screened as potent phase-transfer catalysts for the reaction of aza-Michael cyclization, the key step in the synthesis of letermovir. During the reaction of aza-Michael cyclization, the screened monoquaternary ammonium salt quinine derivative Q1 transferred 7 to 8 with 91.9% yield and 58% ee. The application of Q1 was preferred, due to its enantioselectivity, the possibility of reuse, and the lower cost in large-scale preparation. Furthermore, the racemization condition of letermovir enantiomer was also explored for the possibility to develop the resolution/racemization process. With the optimal catalyst Q1 in hand, the synthesis of letermovir may be more convenient and economical in the future.

Results of measuring the conductivity of electrolytes with ionic liquids (IL) based on quaternary ammonium salts, promising for innovative lithium-sulfur batteries are presented. The conductivity of IL in a propylene carbonate-dimethylformamide mixture is 5.2·10-4. Sm/cm depending on the solvent ratio. The presence of lithium salt leads to higher values up to 8.9·10-3 Sm/cm.

A novel series of 1-[3-{3,5-bis(benzylidene)-4-oxo-1-piperidino}-3-oxopropyl]-4-piperidone oximes 3a–h and related quaternary ammonium salts 4a–h were prepared as candidate antineoplastic agents. Evaluation against neoplastic Ca9-22, HSC-2 and HSC-4 cells revealed the compounds in series 3 and 4 to be potent cytotoxins with submicromolar CC50 values in virtually all cases. In contrast, the compounds were less cytocidal towards HGF, HPLF and HPC non-malignant cells revealing their tumour-selective toxicity. Quantitative structure–activity relationships revealed that, in general, both cytotoxic potency and selectivity index figures increased as the magnitude of the Hammett sigma values rose. In addition, 3a–h are cytotoxic towards a number of leukemic and colon cancer cells. 4b,c lowered the mitochondrial membrane potential in CEM cells, and 4d induced transient G2/M accumulation in Ca9-22 cells. Five compounds, namely 3c,d and 4c–e, were identified as lead molecules that have drug-like properties.