Preparation and spatial structure of methyl ether of 7β-methyl-D-homo-6-oxaestra-1,3,5(10),8(9)-tetraen-17a-one

Procedure of preparation of 7β-methyl-D-homo-6-oxa-1,3,5(10),8,(9)-estratetraen-17a-one methyl ether has been developed; the product conformation in the solution has been studied by NMR spectroscopy. Comparison of the experimental data with simulation of similar compounds docking into the ligand-binding pocket of the estrogens α-receptor has suggested that such steroids are promising for preparation of biologically active substances whose action would not be mediated by the estrogens receptors.     

Picogram determination of estrogens in water using large volume injection gas chromatography–mass spectrometry

In this study, a simple and efficient large volume injection gas chromatography–mass spectrometry (GC-MS) method, via a programmable-temperature vaporizer (PTV) inlet, has been developed and applied in the determination of estrogens in environmental water samples without a prior derivatization process. Three commonly used estrogens estrone, 17 β-estradiol and 17 α-ethynylestradiol were selected as target compounds for this study. It has been demonstrated that the type of gas chromatograph liner and the initial inlet temperature can greatly affect the response intensity of estrogens. Three different types of PTV liners have been studied; the multibaffle liner generated the strongest response intensities towards the estrogen analytes. The results showed that the response intensities of estrogens reduced sharply while the initial inlet temperature increased. Various instrument conditions and sample preparation methods were studied in detail. The optimized method has been validated with good linearity, precision and accuracy. The method detection limit of each estrogen was found to be 0.041 ng/L for estrone, 0.046 ng/L for 17 β-estradiol and 0.031 ng/L for 17 α-ethynylestradiol. To the best of our knowledge, these results represent the best sensitivities achieved for estrogens analyzed in water samples via traditional GC-MS method without a derivatization process. This method has been successfully applied in the analyses of different water samples.     

Environmental effects of endocrine disruptors and current methodologies for assessing wildlife health effects

In recent years, there has been increasing concern regarding environmental estrogens. Reported adverse effects in wildlife are declines in populations, increases in cancers, reduced reproductive function and disrupted development of immune and nervous systems. These chemicals have been shown to mimic or antagonize the action of endogenous hormones of particular interest. Due to the widespread distribution of these xenoestrogens, there is a need for screening and risk evaluation of these endocrine disruptors. We need an overall picture of how we are exposed to environmental estrogens, and we need a method to determine the exact levels of exposure.     

Synthesis of steroid hormones

Conclusions Methods have been developed for preparing steroid hormones (including estrogens, anabolics, contraceptives, and provitamins of the D group), which are important in medicine and veterinary practice, and also insect ecdysis hormones, which are promising materials for use in combating insects that are harmful to crops. A scheme of total synthesis has been developed into a process flow plan and has been put into commercial use. The proposed paths of synthesis also offer the possibility of synthesizing numerous steroid compounds with greatly different types of structure; the properties of these compounds, particularly their physiological action, will be the object of future research.This article is published in accordance with the decision of the editorial board of the journal, July 19, 1980.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 299–317, February, 1982.     

Decontamination of some radioactive effluents by means of ceramic filters

The paper deals with the use of some ceramic materials for the removal of⁵⁵⁺⁵⁹Fe³⁺ and⁶⁰Co²⁺ ions from residual waters. For this purpose, chamotte powder has been used both by itself or in a mixture with aluminium oxide. The pastes obtained by wetting these materials have been shaped in the form of crucibles. The radioactive ions which exist in residual effluents, have been retained to a large extent on these filters. Separately, the leaching of radioactive ions previously retained on the filtering mass, has been studied under the influence of water and of diluted solutions of hydrochloric acid or sodium chloride.     

Simultaneous determination of endocrine-disrupting phenols and steroid estrogens in sediment by gas chromatography-mass spectrometry

A simple and effective method has been developed to simultaneously determine endocrine-disrupting phenolic xenoestrogens and steroid estrogens in sediment by using ultra-sonicated extraction in combination with silica gel fractionation, derivatization with pentafluropropionic anhydride, and gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring mode (SIM). Satisfactory recoveries have been obtained for phenolic xenoestrogens and steroid estrogens. The method enables the determination of targets at concentrations of lower nanogram-per-gram in sediments. The method has been successfully applied to the sediments collected from Pearl River Estuary (PRE), South China Sea, China. Nonylphenol and bisphenol-A (BPA) were detected in the range from 204.2 to 664.5 ng/g and 0.6 to 4.0 ng/g, respectively. None of the estrogens were found in the sediment samples.     

Evaluation of two aquatic passive sampling configurations for their suitability in the analysis of estrogens in water

The presence of estrogens in the aquatic environment has been the target of several studies in the last decade. Newly developed passive sampling techniques for polar organic chemicals show great promise for the assessment of long-time exposure of aquatic organisms to emerging contaminants. In the present work, two configurations of the Chemcatcher^® passive sampler have been tested for their applicability to the analysis of seven estrogens in water. Accumulation experiments in the laboratory, to calculate the uptake rates, and a field trial show that the polar configuration of this device may be used for the efficient sampling and determination of estrogens in water. Time weighted average concentrations were determined in the field trial and compared with spot sampling concentrations. The detection of estriol using passive sampling, although not found with spot sampling, clearly demonstrates the value of this technique in assessing relevant concentrations of estrogens in the aquatic media.     

Synthesis and study of structure and physicochemical properties of dicopper(II) (diaqua)benzene-1,2,4,5-tetracarboxylate

Layered complexes of copper(II) with benzene-1,2,4,5-tetracarboxylic acid has been prepared for the first time. The data of elemental analysis, X-ray diffraction analysis, IR spectroscopy, and differential thermal analysis have confirmed the purity of the complex compound. Its chemical composition has been elucidated, and thermal decomposition has been studied. The prepared complex contained no water molecules, and the polymeric layered structure has been retained.     

Intercalation compounds between nicotine and a high surface area Saponite

The retention of nicotine by a high surface area saponite has been studied using two methods: (1) in repose at room temperature, and (2) heating at 70 °C under reflux. Different contact times were considered for each method. The intercalation compounds obtained were studied by chemical analysis, X-ray diffraction, infrared spectroscopy and thermal analysis. Nicotine is retained both in the interlayer region and at the edge of clay particles. The amount of nicotine retained in the interlayer region has been calculated from thermal analysis and CHN measurements.     

On evolution of non-linear waves in polytropic reacting gases

In this paper we have studied the behavior of wave motion as propagating wavelets and their culmination into shock waves in polytropic reacting gases with same \(\gamma \)-law. An expansion wave resulting from the action of receding piston has been considered and the solution to this problem has been obtained. The propagation of weak waves has been considered and the flow variables in the region bounded by the piston and the characteristic wave front have been found out. The expansive action of a receding piston undergoing an abrupt change in velocity has been discussed. Central expansion fan and shock fronts have been studied and the solutions up to first order in the physical plane have been obtained. The effects of reaction mechanism on the solutions have been analyzed in each case.     

Measurement of endogenous estrogens: analytical challenges and recent advances

Recent developments in the analysis of endogenous estrogens (including both free and conjugated estrogens) are reviewed. Largely due to urging by some cancer researchers, new demands are now being placed on such measurements in terms of sensitivity, throughput, multi-analyte detection and accuracy. Especially high sensitivity is required for detecting estrogens in serum from postmenopausal women, children and men, where concentrations at the low pg/ml level are encountered, and one would prefer to test much less than 1 ml of serum. Aside from throughput, meeting all of these demands may be beyond the reach of immunoassay, the method that has created and continues to dominate this field. Both HPLC and GC versions of mass spectrometry are emerging that have some potential to improve the testing of physiological samples for endogenous estrogens. The following topics are covered in this review: related analyses (e.g. detection of estrogens in environmental samples such as water, where 1-l samples can be collected to provide ng amounts of estrogens); structure and metabolism of estrogens; biological actions (with an emphasis on their role in cancer); immunoassays; HPLC with electrochemical detection; GC-ECD; and various forms of mass spectrometry.     

Use of borohydride reduction in the separation of estrogen carbonyls

The chromatographic behavior of the estrogen carbonyls, equilenin, equilin, and estrone, and their respective sodium borohydride reduction products has been studied. The separation of the 17 alpha-hydroxy reduced compounds is superior to the separations achieved for the parent carbonyls using both reversed-phase and normal-phase systems. The reductions appear quantitative by the chromatographic systems used but other work indicates that a small quantity of 17 alpha-hydroxy isomer is produced. The separations developed here have been used in the identification of 9-dehydroestrone, an impurity in estrone, and in the identification of the estrogens in a commercial aqueous suspension of estrogenic substances.     

Mathematical correlations for predicting protein retention times in hydrophobic interaction chromatography

In our work we performed a combinatorial synthesis in aqueous medium to prepare peptide libraries from which we would select amino acid sequences with binding properties towards estrogens. We prepared an affinity solid-phase by using a tetrapeptide with good selectivity and affinity towards the estradiol (K> 10(4) M(-1)). Samples of estrogens in buffer, in tap water and in river water were applied to our column in which they were retained (k' > 116). These could only be eluted in a few millilitres of methanol mobile phase. In all cases there were quantitative recoveries. The pre-concentration studies were promising.     

A comparison of three analytical techniques for the measurement of steroidal estrogens in environmental water samples

Research into the analysis and monitoring of steroidal estrogens has grown significantly over the last decade, resulting in the emergence of a range of applicable techniques. In this study, three popular techniques, gas chromatography-mass spectrometry (GC-MS), gas chromatography-tandem mass spectrometry (GC-MS-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS) for the analysis of three highly potent steroidal estrogens in the aquatic environment have been compared. It has been observed that overall, the three techniques appear comparable in generating similar estrogen concentrations for river and effluent samples. Of the three techniques, the GC-MS technique is the simplest to operate, but fails to detect the estrogens at the lower-end of environmentally relevant concentrations. The tandem MS techniques are more selective than MS, and therefore able to detect lower concentration levels of the three steroidal estrogens of interest. However, the LC-MS-MS technique is more susceptible to matrix interferences for the analysis of samples, resulting in a reduction of the signal-to-noise ratio and a subsequent reduction in reliability and stability compared to GC-MS-MS. With the GC-MS-MS technique offering increased selectivity, the lowest limits of detection, and no false positive identification, it is recommended to be the preferred analytical technique for routine analysis of estrogens in environmental water samples.     

Chain scission of butyl rubber by nitrogen dioxide in absence and presence of air

The chain scission reaction suffered by butyl rubber due to NO₂ (0.01-1 mm Hg) has been studied in the presence and absence of air. It has also been studied as a function of temperature (25–65°C) at constant NO₂ pressure, again in absence and presence of 1 atm of air. Reaction mechanisms which are in good agreement with the experimental results have been formulated. The synergistic action of O₂ and NO₂ has been pointed out.     

Synthetic and modified isoflavonoids XV. Interaction of synthetic analogs of isoflavones with hydrazine hydrate and its derivatives

The reactions of 1,3-benzodioxolane, 1,4-benzodioxane, and 1,5-benzodioxepane analogs of isoflavones with hydrazine derivatives have been studied. It has been found that under the action of hydrazines the new isoflavones recyclize into 3,4-diarylpyrazones. Their structures have been confirmed by their PMR spectra.Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 629–633, September–October, 1994.     

Nitration of imidazoles with various nitrating agents

The nitration of imidazole and its derivatives has been studied. The action of sulfuric-nitric nitrating mixture on imidazole and its nitro derivatives has given di- and trinitroimidazoles. The action of a mixture of nitric acid and acetic anhydride on the mononitroimidazoles has given the corresponding N-nitro derivatives, and some of their properties have been studied.     

Analysis of free estrogens and their conjugates in sewage and river waters by solid-phase extraction then liquid chromatography-electrospray-tandem mass spectrometry

Summary ‘Free’ steroidal estrogens have been identified as compounds possibly responsible for endocrine-disruption of aquatic fauna populating rivers in which municipal sewage-treatment plants (STP) discharge their effluents. Natural and synthetic estrogens are excreted, as glucuronides and sulfates, by man, in the urine but these are bioconverted back to the unconjugated forms in wastewater discharges. For this reason we have developed a sensitive analytical procedure, without derivatization, for identification and quantitation of conjugated and free estrogens in surface and waste waters. The hormones were extracted and fractionated, by use of Carbograph cartridges, into neutral and acid fractions which were then analyzed by liquid chromatography-tandem mass spectrometry. Recoveries were between 66 and 100% and limits of detection (LOD) between 15.0 and 0.003 ng L⁻¹, depending on the compound and the water matrix. When this methodology was applied to real sewage and river water we could measure the main free estrogens at ng L⁻¹ levels. Among the conjugates we always observed the presence of estrone 3-sulfate (at levels between 8.0 and 0.5 ng L⁻¹).     

Investigations of pyrans and related compounds

The action of phosphorus oxychloride in DMFA on 4-hydroxy-3-nitrocoumarin has given 4-chloro-3-nitrocoumarin, by the reaction of which with amines and ammonia 4-amino-3-nitrocoumarins have been synthesized; some of their physicochemical properties have been studied.For communication XLV, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 885–890, July, 1973.     

Synthesis and Properties of Some New Nicotinoyl Isocyanates and Their Fragmentation under Electron Impact

A convenient preparative route for synthesis has been developed and nicotinoyl isocyanates (NIC) have been obtained for the first time by the action of oxalyl chloride on amides of substituted nicotinic acids. A procedure has been found for suppressing the formation of hydrochlorides of nicotinoyl amides by the competing reaction of HCl with the initial amides of nicotinic acids. The special features of the fragmentation of nicotinoyl isocyanates under electron impact have been studied.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 549–553, April, 2005.