Aminyloxide (nitroxide)-XXVI: ESR-spektroskopische untersuchung von hydrazonyloxiden. Ermittlung der spindichteverteilung

The so-called “Bergmann oxide” 4a and the related compounds 4b-i dissociate reversibly to the corresponding radicals 5 at elevated temperatures. Analysis of the ESR spectra reveals that in 5a-f the unpaired electron is delocalized over the entire molecule. On the other hand the strongly reduced spin density at the β-carbon atom in 5h-i as well as in 7 indicates a twisting about the N,N-bond in these radicals, whereas m 5g the bond between the β-carbon atom and the group Ar¹ is twisted. The results of spin density calculations for radicals 5 are in agreement with the experimentally estimated spin densities. In spin trap experiments with nitrosobenzene or nitrones respectively, 5a reacts at the β-carbon atom, indicating this position as the most reactive one.     

Double asymmetric induction in benchrotrene derivatives

Attachment of a Cr(CO)₃ moiety to one of the aromatic rings in rigid diaryl ketones of very low prochirality followed by addition of a chiral and optically pure reagent leads to satisfactory asymmetric induction ~40%. Asymmetric induction is smaller in the case of acyclic systems.     

Reaction of bis(triethylgermyl)mercury with mercurated acid nitriles

Conclusions The exchange reaction of the radicals between bis(triethylgermyl)mercury and mercury derivatives R₂Hg (R=C(Me₂)CN, C(CF₃)₂CN, CH(CN)₂) leads to the formation of unstable Et₃GeHgR compounds. The composition of the decomposition products of these compounds depends on the nature of R.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2800–2802, December, 1977.     

STRUCTURE AND PHOTOBIOLOGICAL ACTIVITY OF 7-CHLORO-1,4-BENZODIAZEPINES. STUDIES ON THE PHOTOTOXIC EFFECTS OF CHLORDIAZEPOXIDE, DESMETHYLCHLORDIAZEPOXIDE AND DEMOXEPAM USING A BACTERIAL INDICATOR SYSTEM

The photobiological activity of chlordiazepoxide, an active ingredient of the drug Librium, which is known to induce phototoxic effects, and two of its metabolites, desmethylchlordiazepoxide and demoxepam, was investigated. Upon irradiation of these biologically active compounds with longwave UV light, the main decomposition product formed is an oxaziridine. Using a strain of Salmonella typhimurium as a test organism for cytotoxicity, it could be demonstrated that not only the drug itself, but also the major mammalian metabolites are phototoxic and, furthermore, that the respective oxaziridines are responsible for the toxic effects found upon irradiation. A close relationship appears to exist between the phototoxicity of the nitrones and the toxicity in the dark of their respective oxaziridines. Investigations of the photobiological activity of a few closely structurally related benzodiazepines could establish that a 4-oxide moiety in the benzodiazepine nucleus is the structural characteristic responsible for the appearance of phototoxicity; in those compounds which contain a 4-oxide in the benzodiazepine nucleus, photo-decomposition to a toxic oxaziridine is observed, while the analogues lacking the 4-oxide moiety do not show this characteristic and, therefore, no phototoxic effects can be observed. Finally, mutagenicity tests performed with the same bacterial indicator as used for phototoxic studies, and including chlorpromazine as a positive reference compound, indicate that under the present experimental conditions photoproducts formed upon irradiation of chlordiazepoxide and its metabolites with longwave UV light do not exert a mutagenic effect.     

Structure and Vibrational Spectra of 1:1 Chloranilic Acid (CLA)—Tetramethylpyrazine (TMP) Complex

In searching for new molecular materials the crystals of 1:1 complexes of tetramethylpyrazine (TMP) with chloranilic acid (CLA) were grown. In the crystalline lattice of TMP.CLA infinite chains of hydrogen bonded components are formed. Very strong (d_(O·sN) = 2.692(2) {?}) hydrogen bonds without proton transfer are present. The components of the complex form stacks of parallel arrangement with the distance typical of van der Waals interaction. One can conclude that in packing, interactions via hydrogen bonds play a decisive role. In the IR spectrum one observes a broad, continuous absorption with well resolved trio typical of strong hydrogen bonds. A detailed analysis of IR and Raman spectra in the low frequency region related to deformation vibrations of CH₃ groups shows that strong interaction via hydrogen bonding only slightly affects the dynamics of these groups.     

Screening of psychotropic drugs in human hair based on high-performance thin-layer chromatography and microliquid extraction

The monitoring of the physiological and functional state of personnel from dangerous industries is very important for the ensuring of ecological security. Usually, this involves testing for the consumption of alcohol and drugs of abuse. During the last several years the use of legal psychotropic drugs has increased and the control over these drugs has became an actual problem. As is well known, the long-term history of drugs present in the body is accessible through hair analysis. This is why the aim of our research is to create a screening procedure based on coupling high-performance thin-layer chromatography with microliquid extraction as a psychotropic drug testing method for hair. Some widely distributed antidepressants, neuroleptics, and sedative drugs are chosen for research. The optimal experimental conditions for all of the consequent steps for the screening detection of the model samples are determined. The visual and densitometric detection limits allow for the employment of the proposed technique for a fast and cost-effective analysis of the drugs of abuse.     

Influence of the structure of monoalkyl substituted ketenes upon the rate of their spontaneous hydrolysis in water

The kinetics of spontaneous hydrolysis of monoalkylsubstituted ketenes has been studied. The influence of inductive and steric effects of substituents upon the rate has been quantitatively estimated in terms of -analysis. Increasing length and branching of alkyl substiuents decrease the rate of ketene hydrolysis.     

Stereospecific ion-molecule reactions of anabolic-type steroid tertiary alcohols with proton-donating cations

Isobutane and methane chemical ionization (CI) mass spectra of C-17a-epimeric, 17a-substituted 3-methoxyestra-1,3,5(10),8-tetraen-17a-ols and at C-17-epimeric 17-substituted 3-methoxyestra-1,3,5(10)-trien-17-ols, as well as of some their derivatives, have been studied. In each epimeric pair, the peak intensity ratio [MH-H(2)O](+) / [MH](+) is greater for stereoisomers having an axial (or quasi-axial) hydroxyl group. The same regularity in the peak intensity ratio [MH-CH(3)COOH](+) / [MH](+) is valid for acetates in the D-homo series. The observed quantitative differences in CI mass spectra of epimers are explained by steric hindrance of the attack of the proton-donating cation caused by the angular 18-methyl group. No differences in the ease of elimination of the silanol molecule were observed in CI mass spectra of epimeric silyl ethers.     

Sandwich structures at oil-water interfaces under alkaline conditions

Equilibrium liquid crystal (LC) layer on an interface between crude oils and water was observed at high pH. This layer is composed mainly of sodium naphthenates produced in situ at the water/oil interface. Transient LC layer was also evolved at the interface of aqueous phase of sodium hydroxide solutions and oleic phase of naphthenic acid (NA) solutions as result of a chemical reaction between NaOH and NA. This chemical reaction causes transport process resulting in a disturbance of the interface. Optical observation of this interface disturbance reviled that the interface covered with LC shows considerably lower flexibility as compared to LC free interface. The LC layer eventually dissolves in the water phase at low oil-to-water ratio, while at high oil-to-water ratio it can form an equilibrium phase, which spreads spontaneously at the oil-water interface.     

Transesterification of fatty acid ethoxylates in supercritical methanol, then gas chromatography-mass spectrometric determination of the derived methyl esters, for identification of the initiators

Unknown fatty acid ethoxylate samples have been transesterified in supercritical methanol, using a loop made of a stainless-steel tubing as the reactor vessel. The initiator acids, now present as the corresponding methyl esters, were determined by gas chromatography-mass spectrometry (GC-MS). Quantitative transesterification is achieved by heating a solution of the ethoxylate sample in methanol at 280 degrees C for 10 min under pressure. The influence of reaction time, temperature, and presence of a Lewis acid catalyst has been investigated. The method of transesterification was optimized in respect of low cost, short reaction time, and availability to laboratories with standard analytical equipment.