Anabolic, doping, and lifestyle drugs, and selected metabolites in wastewater—detection, quantification, and behaviour monitored by high-resolution MS and MS n before and after sewage treatment

Municipal wastewater has been examined for steroids, β₂-agonists, stimulants, diuretics, and phosphodiesterase type V inhibitors (PDE type V inhibitors), which are “dual-use-drugs” applied either as anabolic, doping, and lifestyle drugs or for treatment of diverse diseases. To identify their origin, fitness centre discharges under suspicion of being point sources and sewage-treatment plant feed and effluents were sampled and concentrations determined. Sensitive and selective methods for determination and quantification based on solid-phase extraction (SPE) followed by high-performance liquid chromatography–high resolution mass and tandem mass spectrometry (HPLC–(HR)MS and HPLC–MS–MS) were developed and established for analysis of these compounds in wastewater and to assess their effect on the environment. The methods developed enabled quantification at trace concentrations (limit of quantification (LOQ): 5 ng L⁻¹). Of the steroids and stimulants under investigation, testosterone, methyltestosterone, and boldenone or ephedrine, amphetamine, and MDMA (3,4-methylendioxy-N-methylamphetamine) were observed at up to 5 μg L⁻¹ (ephedrine). Of the β₂-agonists salbutamol only, and of the diuretics furosemide and hydrochlorothiazide were confirmed in the extracts. Quite high concentrations of the PDE type V inhibitors sildenafil, tadalafil, and vardenafil and their metabolites were confirmed in fitness centre discharges (sildenafil: 1,945 ng L⁻¹) whereas their concentrations in municipal wastewater did not exceed 35 ng L⁻¹. This study identified anabolic and doping drugs in wastewater for the first time. Results obtained from wastewater treatment plant effluents proved that these “dual-use-drugs”, with the exception of hydrochlorothiazide, were mostly eliminated.     

Tautomerism, Hammett σ, and QSAR

A consideration of equilibrium model-based equations suggests that tautomeric equilibria do not markedly affect observed potency if the tautomer bound represents at least 50% of the compound in solution. Tautomeric equilibria can enhance or attenuate the correlation of potency with Hammett σ. Additionally, tautomeric equilibria can lead to a correlation of potency with σ even in the absence of a correlation of binding with σ.     

Thermal characterization and kinetic analysis of nesquehonite,hydromagnesite, and brucite,using TG–DTG and DSC techniques

Nesquehonite, hydromagnesite, and brucite are important precursors for the preparation of high-purity magnesia (MgO) using magnesium resources from salt lake as raw materials. In this paper, TG–DTG and DSC were used to investigate the thermal decomposition behaviors of the three precursors. Decomposition kinetic parameters at each stage were evaluated based on the TG data using the iso-conversional method. Decomposition mechanisms were determined using the master-plots method. The decomposition temperature range, heat absorption, and kinetic parameters of the three phases were then compared. The most probable mechanism of each stage from the perspective of crystal structure was found to be consistent with the calculation results from the master-plots method. Results led to the conclusion that nesquehonite is the most appropriate precursor for the preparation of high-purity MgO. Further studies on precursor selection and calcining condition selection for the preparation of MgO using bischofite will benefit from this research.     

Viscometric, Acoustical and Spectroscopic Investigation of β-Pinene with Benzene, Toluene, m-Xylene and Mesitylene at 303.15, 308.15 and 313.15 K and Atmospheric Pressure

The densities (ρ), viscosities (η), ultrasonic speeds (u) and spectroscopic data of binary mixtures of benzene, toluene, m-xylene and mesitylene with β-pinene as a common component, over the whole composition range of mole fraction of β-pinene including those of pure components, have been measured at 303.15, 308.15 and 313.15 K, except for the spectroscopic study where the temperature was maintained at 298.15 K. The experimental results deviation in viscosity, deviation in ultrasonic velocity, isentropic compressibility and deviation in isentropic compressibility are discussed in terms of molecular interactions between unlike molecules. The variation of these excess parameters indicates the presence of weak interactions between β-pinene and benzene, toluene, m-xylene and mesitylene molecules. Moreover, the viscosity data are discussed in terms of interaction parameters. The theoretical ultrasonic speed was computed using the Nomoto model, ideal mixing relation, Jacobson’s free length theory and compared with the experimentally measured values. The experimental values are also discussed in terms of FTIR spectroscopy.     

Coupled cluster,MP2, and DFT study of structures,stabilities, vibrations,and bonding properties of XXeOH (X = F,Cl, Br,and I)

The optimized geometries, molecular properties, and stabilities of new noble gas molecules, XXeOH (X = F, Cl, Br, and I), were studied using CCSD, MP2, CAM-B3LYP, and WB97XD methods and large basis sets. All XXeOH molecules showed equilibrium structures with Cs symmetry. The results also showed that some bonds in XXeOH could be presented as a typical ionic bond. An alteration in ion-pair character was observed for IXeOH, showing two OH ^? and IXe ⁺ parts, while in other molecules, they could be presented as XeOH ⁺ and X ^? . Two decomposition routes were proposed for these molecules that showed high exothermic reactions. However, despite their low thermodynamic stabilities, their decomposition rate constants were small and all molecules (except BrXeOH) had high kinetic stabilities, indicating the possibility for identification and characterization of these molecules. However, in addition to the calculation of their vibrational frequencies, NBO atomic charges, and hybridizations, the bonding properties of XXeOH molecules were studied by AIM calculations (to calculate electron densities, bond elipticities, and Laplacian of electron densities) and second-order intramolecular perturbation energies using NBO calculations. Moreover, the ease of formations and relative stabilities of XXeOH molecules were compared using heats of formations, Gibbs free energies of formations and isodesmic reactions. These calculations showed that the stability of XXeOH molecules was decreased from F to I.     

Synthesis and α-glucosidase inhibitory activity of chrysin,diosmetin, apigenin,and luteolin derivatives

Several derivatives have been synthesized from chrysin, diosmetin, apigenin, and luteolin, which were isolated from diverse natural plants. The α-glucosidase inhibitory activity of these compounds was evaluated. The glucosidase inhibitory activity of all derivatives （IC50 〈 24.396 μmol]L） was higher compared with that of the reference drug, acarbose （IC50=563.601 ±40.492μmol/L）, and 1- deoxynojirimycin （IC50 = 226.912± 12.573 μmol/L）. O3＇,O7-Hexyl diosmetin （IC50 = 2.406 ± 0.101μmol/L） was the most potent inhibitor identified. These compounds showed a higher inhibitory ability compared with their precursors except the luteolin derivatives. In general, the inhibitory activity of the synthetic derivatives was enhanced with long alkyl chains at positions 3＇, 4＇ and 7 of the flavonoid.     

Reactions of 3-carene, limonene, and α-pinene nitrosochlorides with imidazole, benzotriazole, and indole

The reactions of terpene nitrosochlorides derived from 3-carene, ??-pinene, and limonene, with simplest azaheterocycles (imidazole, benzotriazole, and indole) were studied. On the base of these transformations, preparative procedures to access chiral oximes bearing azaheterocyclic moieties in the ??-position to the oxime fragment, namely, ??-(1H-imidazol-1-yl)-, ??-(1H-benzo-[d][1,2,3]triazol-1-yl)-, and ??-(1H-indol-3-yl)-substituted terpenic oximes, were developed. Transformations of the studied monoterpene nitrosochlorides into ??-substituted oximes proceeded stereoselectively to give in the moderate yields (30?C60%) the only stereoisomer arising from the attack of the heterocyclic anion from the less hindered side of the intermediate nitroso olefin generated in situ from nitrosochloride.     

γ- and UV-radiation-induced degradation of sphingomyelin,lysosphingomyelin, and related compounds

The experimental data on the formation of final products in the radiolysis of 2-aminoglycerol and lysosphingomyelin (sphingosine phosphocholine) and in the photolysis of N-(2-hydroxypropyl)hexanamide and sphingomyelin suggest the occurrence of the radiation-induced degradation of the above substances with C-C bond cleavage. It was hypothesized that this process occurs by the formation and subsequent degradation of the N-centered radicals of the substrates.     

Preparation, characterization, and catalysis of mecro-catalysts

Because catalysis by metals is a surface phenomenon, many technological catalysts contain small (typically nanometre-sired) supported metal particles with a large fraction of the atoms exposed. Many reactions, such as hydrocarbon hydrogenations, are structure-insensitive, proceeding at approximately the same rates on metal particles of various sizes provided that they are larger than 1 nm and show bulk-like metallic behavior. But the catalytic properties are not known when metal particles become so small that their sizes are indium clusters consisting of several indium atoms. Here the catalytic behavior of precisely defined clusters of just four and six indium atoms on solid supports is shown. It is found that the Ir4 and Ir6 clusters differ in catalytic activity both from each other and from metallic Ir particles.     

Zn~Ⅱ, Ni~Ⅱ, and Mn~Ⅱ Complexes Supported by N-Hydroxy-pyridine-2-carboxamidine: Syntheses,Structures, and Luminescent and Magnetic Properties

The employment of N-hydroxy-pyridine-2-carboxamidine in the coordination chemistry of zinc(Ⅱ), nickel(Ⅱ) and manganese(Ⅱ) under solvothermal conditions is reported. Four complexes of compositions, [Zn2(O2CMe)3{(py)C(NH2)NOH}4](OH)(1), [Zn4(OH)2{(py)C(NH2)-NO}4Cl2]·3MeCN(2), [Ni(SO4)(H2O){(py)C(NH2)NOH}2]·H2O(3) and [Mn(SO4){(py)C(NH2)-NOH}2]n(4), have been synthesized by rationally choosing different metal salts and dexterously employing acetate and sulfate ions as the bridging groups. Luminescent properties for 2 suggested strong emission in the solid state at room temperature. Variable temperature(2.0~300 K) magnetic studies for the linear chain complex 4 indicate weak antiferromagnetic Mn(Ⅱ)···Mn(Ⅱ) exchange interactions.     

Group 3 and lanthanide boryl compounds: syntheses, structures, and bonding analyses of Sc-B, Y-B, and Lu-B σ-coordinated NHC analogues

Reaction of [Ln(CH(2)SiMe(3))(2)(THF)(n)][BPh(4)] (Ln = Sc, Y, Lu ; n = 3, 4) with Li{B(NArCH)(2)}(THF)(2) (Ar = 2,6-C(6)H(3)(i)Pr(2)) formed the first group 3 and lanthanide boryl compounds, Sc{B(NArCH)(2)}(CH(2)SiMe(3))(2)(THF) and Ln{B(NArCH)(2)}(CH(2)SiMe(3))(2)(THF)(2) (Ln = Y, Lu), which contain two-center, two-electron Ln-B σ bonds. All of these systems were crystallographically characterized. Density functional theory analysis of the Ln-B bonding found it to be predominantly ionic, with covalent character in the σ-bonding Ln-B HOMO.     

Polarography��past, present, and future

Polarography was first developed as an automated method of voltage-controlled electrolysis with dropping mercury electrode. The spontaneously renewed pure electrode surface provided reproducible electrochemical results which enabled scientists to work out adequate theory and rich analytical applications. The original method was then instrumentally modified in various ways. Later, hanging mercury drop was added as an alternative indicator electrode??in this way, polarography turned formally into voltammetry with mercury drop electrodes. Beside, in potential-controlled electrolysis, the mercury drop electrodes have been also used in current-controlled electrolysis (chronopotentiometry)??there, it has provided new experimental effects. Polarography has thus gradually covered a wide field of electrolytic methods based on the use of mercury electrodes, in which it continues developing.     

Dicyano and pyridine derivatives of β-carotene: synthesis and vibronic, electronic, and photophysical properties

Density functional theory and time-dependent density functional theory calculations provide pictures of the molecular orbitals involved in the ground and excited states of two cyano derivatives of 8'-apo-β-caroten-8'-al synthesized via an acid-base-catalyzed Knoevenagel condensation reaction. Population analysis shows that the symmetry-allowed transition, S(0) ((1)A(g)) → S(2) ((1)B(u)) based on the C(2h) symmetry is a HOMO (highest occupied molecular orbital) to LUMO (lowest unoccupied molecular orbital) π → π* transition with electron densities located mostly on the polyene chain. Calculated and actual steady-state absorption spectra show similar features with low-energy peak maxima between 550 and 600 nm.     

Phenazineoxonium chloranilatomanganate and chloranilatoferrate: synthesis,structure, magnetic properties,and Mössbauer spectra

Russian Chemical Bulletin - Crystalline compounds (H3O)2(phz)3M2(C6O4Cl2)3·(CH3COCH3) n ·(H2O) n (n = 0?2, M = Mn (1), Fe (3)) were obtained in an acetone-water-tetrahydrofuran...     

Chemistry, commentary, and community: discussion of “an examination of the vaporization enthalpies and vapor pressures of pyrazine, pyrimidine, pyridazine, and 1,3,5-triazine” by Lipkind and Chickos

Vaporization enthalpies for the isomeric diazines were discussed within the context of recent measurements and estimation techniques. It is suggested that pyridazine shows enigmatic behavior.

Henry’s constants and infinite dilution activity coefficients of propane,propene, butane,isobutane, 1-butene,isobutene, trans-2-butene,and 1,3-butadiene in isobutanol and tert-butanol

The Henry’s constants and the infinite dilution activity coefficients of propane, propene, butane, isobutane, 1-butene, isobutene, trans-2-butene and 1,3-butadiene in isobutanol at T = (250 to 330) K and tert-butanol at T = (300 to 330) K are measured by a gas stripping method. The rigorous formula for evaluating the Henry’s constants from the gas stripping measurements is used for data reduction of these highly volatile mixtures. The accuracy of the measurements is about 2% for Henry’s constants and 3% for the estimated infinite dilution activity coefficients. In the evaluations for the infinite dilution activity coefficients, the nonideality of the solute such as the fugacity coefficient and the Pointing correction is not negligible, especially at higher temperatures, and the estimation uncertainty in the infinite dilution activity coefficients includes 1% for nonideality.     

Viscosities for Binary Mixtures of 1-Decanol, Hexane, and Diethylamine at 10, 25, and 40°C

Experimental viscosities provide information on the structure of liquids and are required in the design of processes, which involve fluid flow, mass transfer, or heat transfer calculations. This work reports experimental viscosity data of the binary mixtures: 1-decanol + hexane, 1-decanol + diethylamine, and hexane + diethylamine at 10, 25, and 40°C and atmospheric pressure for the whole range of compositions. The viscosities of the pure liquids and their mixtures were determined using Cannon Fenske viscometers thermostated at ±0.01°C. The estimated error in the measured viscosities was less than ±0.005 mPa-s. The dynamic viscosity and the excess energy of activation for viscous flow were also calculated. The equation of Redlich–Kister was used for fitting the excess properties of the binary mixtures. The excess viscosity shows positive deviations from ideal behavior for the mixtures 1- decanol + hexane and 1-decanol + diethylamine and a small negative deviation for the binary system hexane + diethylamine. The experimental results have been also used to test some empirical and semiempirical equations adopted previously to correlate viscosity composition data.     

Dicyanoanilines as potential and dual inhibitors of α-amylase and α-glucosidase enzymes: Synthesis,characterization, in vitro,in silico,and kinetics studies

The present study comprised of the synthesis of dicyanoaniline derivatives of pyridine, thiophene, furan, and substituted phenyl 1–29. All synthetic derivatives were evaluated for their potential to inhibit α-amylase and α-glucosidase enzymes. The synthesized compounds are classified into three categories A, B, and C based on variable substituents at R₁ and R_2, and the structure–activity relationship was discussed accordingly. Amongst twenty-nine derivatives, 1–29, five compounds 2, 9, 18, 23, and 24 displayed excellent inhibition against α-amylase and α-glucosidase enzymes with the IC₅₀ values ranging between 20.33 ± 0.02–25.50 ± 0.06 µM and 21.01 ± 0.12–27.75 ± 0.17 µM, respectively, while other compounds showed moderate to weak inhibition against both enzymes. Acarbose was used as the positive control in this study. The enzyme kinetic studies showed non-competitive and un-competitive types of inhibition mechanism against α-amylase and α-glucosidase enzymes, respectively. In silico studies have demonstrated the involvement of these molecules in numerous binding interactions within the active site of the enzyme.