Structure, spectra and stability of a tetrafluoromethane-water complex

The complex formed between water and tetrafluoromethane has been studied by infrared matrix isolation spectroscopy and ab initio calculations. The geometries of the CF4-H2O complexes were optimized in two steps at the MP2/aug-cc-pVTZ level of theory. The structure found at this level was reoptimized on the CP-corrected potential energy surface. The interaction energy was partitioned according to the SAPT scheme and the topological analysis of the electron density was performed. The optimized structure corresponds to the nonhydrogen bonded complex with an oxygen atom of water oriented toward the carbon atom of CF4. The infrared spectra of CF4-H2O /Ne(Ar) matrices demonstrate the presence of a well defined CF4-H2O structure in accord with theoretical prediction. Two complex vibrations were identified in the spectra of neon matrices and four vibrations were observed in the spectra of argon matrices. The available experimental data are in accord with the CP-corrected calculated data.     

Facile and Versatile Room-Temperature Synthesis of N,N-Disubstituted Cyanoacetamides from Malonic Ester Chloride

A general method for the synthesis of various N,N-disubstituted cyanoacetamides from readily available methyl malonyl chloride and secondary amines, including sterically demanding aliphatic and aromatic amines, is described.     

Synthesis and Tuberculostatic Activity of Some 1,1-Bis-methylthio-2-nitro-ethene Derivatives

1,1-bis-methylthio-2-nitro-ethene was used as a substrate to the syntheses of new heterocyclic compounds. In the reactions, with 1-phenylpiperazine—the corresponding diaminonitroethane 1 , 1,3-diaminonitropropane, and 1,3-diaminonitropropanol—the nitromethylenotetrahydropyrimidine derivatives 2 and 3 were prepared, whereas, with o-phenylenediamine—2-nitromethyleno-benzimidazole 4 were obtained. In the condensation reactions of compounds 2 , 3 , and 4 with benzoyl isothiocyanate, the products 5 , 6 , and 7 were obtained, and afterwards two of them, 5 and 6 , were transformed into the isothiazolines 8 and 9 .

1,1-bis-(4-phenylpiperazino)-2-nitroethane ( 1 ) was exposed to the action of phenyl isothiocyanate and the derivative obtained ( 10 ) was transformed, in the reaction with phenacylbromide, in to benzoylonitrothiophene 11 . The diazo compounds 12 , 13 , and 14 were obtained in the reactions of nitromethylenotetrahydropyrimidines 2 and 3 and of 2-nitromethylenobenzimidazole 4 with benzenediazonium chloride. The derivatives obtained were tested in vitro for their tuberculostatic activity. The compounds 7 (MIC 8–32 μg/mL) and 14 (MIC 16–63 μg/mL) appeared to be the most active compounds.     

Synthesis,structure and investigations of tuberculosis inhibition activities of new 4‐methyl‐1‐substituted‐1H‐1,2,4‐triazole‐5(4H)‐thione

By the reaction aminomethylation, chloromethylation and acylation of 4‐methyl‐4H‐1,2,4‐triazole‐3‐thiol, 4‐methyl‐1‐substituted‐1H‐1,2,4‐triazole‐5(4H)‐thione 1‐8 were obtained. Molecular structure of the obtained compounds was confirmed by an elemental analysis, IR, ¹H NMR and ¹³C NMR spectra and additionally by X‐ray analysis for 2. Six new compounds 1,2,4‐7 were tested for antibacterial activity against Mycobacterium smegmatis, Mycobacterium phlei and avirulent strain Mycobacterium H₃₇Ra.     

Quality Assessment of Wild and Cultivated Green Tea from Different Regions of China

Natural products have always enjoyed great popularity among consumers. Wild tea is an interesting alternative to tea from intensive plantations. The term “wild tea” is applied to many different varieties of tea, the most desirable and valued of which are native or indigenous tea plants. Special pro-health properties of wild tea are attributed to the natural conditions in which it grows. However, there are no complex studies that describe quality and health indicators of wild tea. The aim of this research was to evaluate the quality of wild and cultivated green tea from different regions of China: Wuzhishan, Baisha, Kunlushan, and Pu’Er. The assessment was carried out by verifying the concentration of selected chemical components in tea and relating it to the health risks they may pose, as well as to the nutritional requirements of adults. Wild tea was characterized by higher micronutrient concentration. The analyzed teas can constitute a valuable source of Mn in the diet. A higher concentration of nitrates and oxalates in cultivated tea can be associated with fertilizer use. The analyzed cultivated tea was a better source of antioxidants with a higher concentration of caffeine. There were no indications of health risks for wild or cultivated teas.     

Electroporation and Electrochemotherapy in Gynecological and Breast Cancer Treatment

Gynecological carcinomas affect an increasing number of women and are associated with poor prognosis. The gold standard treatment plan is mainly based on surgical resection and subsequent chemotherapy with cisplatin, 5-fluorouracil, anthracyclines, or taxanes. Unfortunately, this treatment is becoming less effective and is associated with many side effects that negatively affect patients’ physical and mental well-being. Electroporation based on tumor exposure to electric pulses enables reduction in cytotoxic drugs dose while increasing their effectiveness. EP-based treatment methods have received more and more interest in recent years and are the subject of a large number of scientific studies. Some of them show promising therapeutic potential without using any cytotoxic drugs or molecules already present in the human body (e.g., calcium electroporation). This literature review aims to present the fundamental mechanisms responsible for the course of EP-based therapies and the current state of knowledge in the field of their application in the treatment of gynecological neoplasms.     

Evaluation of the Antioxidant,Cytoprotective and Antityrosinase Effects of Schisandra chinensis Extracts and Their Applicability in Skin Care Product

Plant extracts have been widely used for skin care for many centuries, and nowadays, they are commonly applied for the development and enrichment of new cosmetic preparations. The present study aimed the assessment of the biological activity of aqueous Schisandra chinensis extracts as a potential ingredient of skin care products. The aspects studied involved the ability to neutralize free radicals, impact on viability and metabolism of keratinocytes, as well as tyrosinase inhibitory potential. Our study showed that aqueous S. chinensis extracts have a positive effect on keratinocyte growth and have high antioxidant potential and strong tyrosinase inhibitory activity. UPLC-MS analysis revealed that three groups of phenolic compounds were predominant in the analyzed extract, including lignans, phenolic acids and flavonoids and protocatechiuc and p-coumaryl quinic acids were predominant. Moreover, microwave-assisted extraction, followed by heat reflux extraction, was the most effective for extracting polyphenols. Furthermore, a prototypical natural body washes gel formulation containing the previously prepared extracts was developed. The irritation potential and viscosity were assessed for each of the formulations. The study demonstrated that the addition of these extracts to body wash gel formulations has a positive effect on their quality and may contribute to a decrease in skin irritation. In summary, S. chinensis aqueous extracts can be seen as an innovative ingredient useful in the cosmetic and pharmaceutical industry.     

New synthesis of coloured dihydrofurylium salts

A new synthesis has been described for coloured dihydrofurylium salts of the hemicyanine type based on the reaction of 2,2,5-trisubstituted 3-benzoyl-methylidene-2,3-dihydrofurans with organomagnesium or organolithium compounds, tertiary aromatic amines or 1,1-diarylethylenes.

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Eine neue Synthese von DihydrofuryliumfarbsalzenVorläufige Mitteilung

Zusammenfassung Es wurde eine neue Synthese für Dihydrofuryliumfarbsalze beschrieben. Die Synthese gründet sich auf die Reaktion von 2,2,5-trisubstituierten 3-Benzoylmethyliden-2,3-dihydrofuranen mit den Magnesium- bzw. Lithiumorganischen Verbindungen, tertiären aromatischen Aminen oder unsymmetrischen Diarylethylenen.

     

Dimerization of the keto tautomer of acetohydroxamic acid-infrared matrix isolation and theoretical study

Dimerization of the keto tautomer of acetohydroxamic acid has been studied using FTIR matrix isolation spectroscopy and DFT(B3LYP)/6-31+G(d,p) calculations. Analysis of CH3CONHOH/Ar matrix spectra indicates formation of two dimers in which two intramolecular CO...HON bonds within two interacting acetohydroxamic acid molecules are retained. A chain dimer I is stabilized by the intermolecular CO...HN hydrogen bond, whereas the cyclic dimer II is stabilized by two intermolecular NH...O(H)N bonds. Twelve vibrations were identified for dimer I and six vibrations for dimer II; the observed frequency shifts show a good agreement with the calculated ones for the structures I and II. Both dimers have comparable binding energies (DeltaE(ZPE)(CP)I, II=-7.02, -6.34 kcal mol-1) being less stable than calculated structures III and IV (DeltaE(ZPE)(CP)III, IV=-9.50, -8.87 kcal mol-1) in which one or two intramolecular hydrogen bonds are disrupted. In the most stable 10-membered cyclic dimer III, two intermolecular CO...HON hydrogen bonds are formed at expense of intramolecular hydrogen bonds of the same type. The formation of the less stable (AHA)2 dimers in the studied matrixes indicates that the formation of (AHA)2 is kinetically and not thermodynamically controlled.     

NMR probing of structural peculiarities in ionic solutions close to critical point

(1)H, (23)Na, (35)Cl, (79)Br, and (81)Br NMR chemical shifts (delta) and signal half widths (Delta(12)) have been measured in aqueous electrolyte mixtures [tetrahydrofuran/H(2)ONaCl and 3-methylpyridine (3MP)H(2)ONaBr] at different mass fractions of salt (X) in the one-phase region, close to their lower critical solution points (T(CL)). Discontinuous changes in slope of delta=f(X) and Delta(12)=f(X) have been found in (23)Na and (81)Br NMR spectra of 3MP/water/NaBr solution at X approximately 0.1 and T=301 K. The dependency of (1)H NMR signals of 3MP is continuous over the whole investigated range of X=0.002-0.2, whereas changes in the slope of H(2)O chemical shifts are hardly noticeable. In the two-phase region, i.e., at T>T(CL), a doubling of all NMR signals has been observed. The sensitivity of NMR parameters depends more on composition of solution for anions (Cl(-) and Br(-)) than for cations (Na(+)). A very strong relaxation effect for (81)Br nuclei with relaxation rates reaching 14 000 s(-1) was observed. The results are interpreted in terms of ion-molecular clustering and changes in coherency of dipole configurations of water molecules during supramolecular restructuring of solutions.