Chemische Vitamin D<Subscript>3</Subscript>-Bestimmung in Lebertran

The different aspects of Vitamin D₃ determination and the data reported in the literature are discussed. The spectrophotometric determination of Vitamin D₃ in cod-liver oil is carried out after the alkaline saponification, extraction of unsaponified parts, precipitation of accompanying sterols and the column- and thin-layer chromatographic purification and separation of vitamin D₃ on 40 cm plates from other vitamins. The dyestuff α-naphtholbenzein is suited well as standard substance for the better location and identification of vitamin D₃ zone on the thin-layer plate. The results obtained from the chemical method were checked through the simultaneous biological determination.     

Electron-impact induced fragmentation of thiirene and thiophene dioxides

The electron impact mass spectra of several substituted thiirene and thiophene oxides and dioxides have been investigated using both low and high resolution mass spectrometry. The predominant fragmentation process in the spectra of the thiirene compounds is the elimination of the hetero (SO or SO₂) function and formation of a substituted acetylene ion. The 5-membered ring thiophene dioxides exhibit mainly elimination of SO rather than SO₂. Plausible mechanisms leading to the formation of the principal ions are proposed on the basis of metastable transitions.     

Selektivierung geringer Mengen Kupfer mit Polyäthylenimin-Zellulose

Zusammenfassung Polyäthyleniminzellulosen sorbieren Cu²⁺ durch koordinative Bindung als Zentralion des sekundären Stickstoffs des Polyäthylenimins im P_H-Bereich 3,5 bis 4,5 selektiv aus verd. Lösungen. 10g Kupfer können von 10⁵fachen Überschüssen anderer Übergangsmetalle separiert, mit verd. Salzsäure eluiert und mit Diäthyldithiocarbamat photometrisch bestimmt werden. Das Verfahren eignet sich zur Erfassung von 0,001% Kupfer in Zink, Mangan, Kobalt, Nickel, Cadmium und Aluminium sowie aus Lösungen, deren Kupfergehalt 0,02 ppm beträgt.

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Selectivation of small amounts of copper with polyethyleneimine-cellulose

Summary Polyethyleneimine celluloses selectively sorb Cu²⁺ from dilute solutions through coordinative bonding as central ion of the secondary nitrogen of polyethyleneimine in the p_H-range of 3.5–4.5. 10g of copper may be separated from 10₅-fold excesses of other transition metals, then eluted with dilute hydrochloric acid and determined photometrically with diethyldithiocarbamate. The method is suitable for determining 0.001% copper in zinc, manganese, cobalt, nickel, cadmium, and aluminium as well as in solutions whose coppercontent is 0.02 ppm.

     

Polarographlc analysis for corticosteroids: Part 5. Reduction mechanism of halogen-containing corticosteroids and analysis of some preparations

In fluprednisolone and chloroprednisone acetate, the polarographic reduction of the carbon—halogen bond in position 6 occurs first. The carbanion—enolate formed is reduced at the dropping mercury electrode at more negative potentials than the conjugate acid. Controlled potential electrolysis at a mercury pool electrode where the carbanion—enolate can be protonated, yields the unsaturated ketone. Polarographic reduction of clobetasol-17-propionate and of clobetasone-17-butyrate results in cleavage of the C—Cl bond in the side-chain. This process is followed by reduction of the α,β-unsaturated ketone in the A-ring. Analytical methods for the determination of these compounds in ointments, creams and eye/ear drops gave results with standard deviations of 1–2%.     

On the synthesis and animation of 5-chloro-and 5-bromo-1,7-naphthyridine

A new synthesis of 5-chloro- and 5-bromo-1,7-naphthyridine, using 8-amino-1,7-naphthyridine as starting material is described. On amination with potassium amide in liquid ammonia, the 5-bromo compound undergoes a tele-amination into 8-amino- and 2-amino-1,7-naphthyridine and a Chichibabin reaction yielding 8-amino-5-bromo-1,7-naphthyridine. The reaction with the 5-chloro compound occurs at a much lower rate than the 5-bromo compound and only gives 8-amino-5-chloro-1,7-naphthyridine in a small yield. Convincing ¹H-nmr evidence is presented, showing that the 5-bromo- and 5-chloro-1,7-naphthyridine give addition of the amide ion at position 8 and that the 5-chloro compound also gives addition at position 2.     

The photochemistry of benzotricyclo[3.1.0.02,6]Hex-3-ene1

Irradiation of $\text{1}$ in methanoi with λ 254 nm yields $\text{3}$ and $\text{4}$ as the main primary products which result from the excited singlet state hy initial cyclopropane bond homolysis, but no primary photosolvolysis products.     

Photobinding of ketoprofen in vitro and ex vivo

Ketoprofen (KP), a non-steroidal anti-inflammatory drug of the 2-aryl propionic class, has been shown to produce photoallergic side effects as well as cutaneous photosensitizing properties that induce other phototoxic effects. In the present study we investigated photobinding of ketoprofen to both human serum albumin (HSA), a model protein, and to ex vivo pig skin and its photodegradation. Results demonstrate that photoadduct formation and photodegradation progressively increased with irradiation time where they reach a maximum. Maximum photobinding to the viable layer of the epidermis was about 7-8% of the initial radiolabelled KP added, in the region of 15-30 min UV irradiation. These results were comparable to in vitro results that were seen with photobinding of KP to HSA; in this case, the quantity of covalently bound material was approximately 10% of the initial, after a maximum of 18 min irradiation. It was found by HPLC analysis that the KP decrease is accompanied by an increase of the corresponding photoproduct, decarboxylated ketoprofen (DKP). The yield of DKP reaches a maximum at around 15 min. DKP appears to play an important role in vitro and ex vivo, being the major photoproduct and responsible for the photobinding process. Using micro-autoradiographical techniques we investigated the penetration and distribution of ketoprofen in ex vivo pig skin in greater detail. It was apparent that percutaneous absorption was taking place and that most of the ketoprofen was predominately localised in fibroblasts in the papillary dermis. No other specific localisation within the skin architecture was identified. Although there were differences in the quantities of bound ketoprofen within the different layers of the skin, these levels did not appear to correlate with irradiation time.     

Second virial coefficients of asymmetric top molecules

A short self-contained derivation is given for the second virial coefficient B2(T) of a gas consisting of identical interacting asymmetric rigid rotors. The resulting expression is correct through variant Planck's over h2. First, the canonical partition function is derived by means of an variant Planck's over h expansion of exp[-H/(k(B)T)] due to Friedmann [Adv. Chem. Phys. 4, 225 (1962)]. The present work applies angular momentum operators and known facts from angular momentum theory. It is considerably more accessible than Friedmann's exposition, which is not based on angular momentum operators, but instead on explicit derivatives with respect to Euler angles. The partition function obtained from the variant Planck's over h expansion is applied to the derivation of an expression for B2(T) that is identical in appearance to the expression for symmetric rotors of T Pack [J. Chem. Phys. 78, 7217 (1983)]. The final equation in this work is valid for rigid rotors of any symmetry.     

Zur Photochemie von Allylaryläthern. 55. Mitteilung über Photoreaktionen

The photochemical reactions of different allyl aryl ethers (Scheme 3) were investigated in hydrocarbons (Chap. 3.1) and in alcoholic solvents (Chap. 3.2). The composition of the photoproducts depended very much on the nature of the solvent. Irradiation (3–95 h) of different methyl substituted allyl aryl ethers ( 1, 3, 5, 7 and 11 ) with a low pressure mercury lamp (λ_Emiss. = 254 nm; 6 or 15 Watt) under argon (quartz vessel) resulted in the formation of 2-, 3– and 4-substituted phenols, dienones and products of consecutive reactions (Tables 1–4 and 6). The results suggested that all products were formed by homolytic cleavage of the C? O bond in the singlet state of the ethers to intermediate radical-geminates (Scheme 5) followed by radical recombination of the two fragments. No products were formed by concerted processes (Table 5, Schemes 5 and 6). Upon irradiation of allyl aryl ethers lacking alkyl substituents at position 4 ( 1 and 5 ) in protic solvents, mainly 2- and 4-allylated phenols were obtained (Tables 1 and 4); 3-allylated phenols were formed only in small amounts (0.02%). However, in aromatic hydrocarbons or cyclohexane 3-allylated phenols were obtained from 1 , 5 and 11 in significant amounts (3–11%; Tables 1, 4 and 6). E.g., upon irradiation of allyl-2,6-dimethyl-2,4-cyclohexadien-1-one ( 6 ) besides 3- and 4-allyl-2, 6-dimethyl-phenol ( 23 and 24 ). Irradiation of 5 in methanol afforded 23 and 6 only in traces, whereas 24 was the main product.     

Calculation of χ)(3) in He including configuration interaction for XUV photons

We calculate the third-order susceptibility in He for photon energies from 19.5 eV to 24.5 eV in a configuration-interaction calculation, and discuss the role of autoionizing states as a means of enhancing harmonic generation.