An optically active vinyl sulfoxide copolymer and the configuration of sulfoxide adjacent to radical or anionic sites

Optically active vinyl p-tolyl sulfoxide was synthesized and copolymerized with styrene to produce an optically active copolymer. The question of the configuration of sulfur in a sulfoxide when adjacent to a radical site is discussed. The configuration of sulfur in a sulfoxide is proven to be nonplanar when adjacent to an anionic site.     

Synthese de s-triazolo[4,3-d] et [1,5-d] triazines-1,2,4

2-substituted s-triazolo[1,5-d] and 3-substituted s-triazolo [4,3-d]-1,2-4-triazine 8-ones were obtained starting from 5-(3)-alkyl-3(5)-carboxyhydrazino-1,2,4 triazoles and ethyl orthoformate. However, the same reaction was not found to be an efficient one in the case of 5(3)-β-D-ribofuranosyl-3(5)-carboxyhydrazino-1,2,4 triazole.     

TOPICAL UROCANIC ACID ENHANCES UV-INDUCED TUMOUR YIELD AND MALIGNANCY IN THE HAIRLESS MOUSE

Epidermal urocanic acid has been postulated to be the mediator of the specific state of immunosuppression induced by UV irradiation, by which UV-initiated tumour cells are able to evade normal recognition and can survive to grow progressively into malignant tumours. These experiments demonstrate that topical application of UV-irradiated urocanic acid systemically suppresses the contact type hypersensitivity response to oxazolone in hairless mice. In addition, topically applied urocanic acid markedly increases the overt tumour yield and the degree of malignancy in hairless mice exposed chronically to daily minimally erythemal doses of simulated solar UV light. Topical urocanic acid also increases the number of latent UV-initiated tumours, detectable by croton oil promotion. Therefore UV photoproducts of urocanic acid can both systemically suppress contact hypersensitivity in the epidermis, and also enhance early survival of UV-initiated tumour cells resulting in augmentation of UV photocarcinogenesis.     

Matrixreaktion von GaF mit o-atomen: ir-spektrum von OGaF

It is possible to synthesize OGaF in an argon matrix by co-condensation of GaF with O atoms. The stretching vibrations of this compound are found at 943 and 690 cm⁻¹ (¹⁶O⁶⁹GaF). An exact calculation of the force field is possible with the aid of the observed ¹⁶O/¹⁸O and ⁶⁹Ga/⁷¹Ga shifts. The following force constants are found: f(GaO) = 6.32; f(GaF) = 4.69; f(GaO/GaF) = −0.1 [10²Nm⁻¹]     

Ligand exchange reactions of ferrocene with phenanthrene or 9,10-dimethylphenanthrene in the presence of aluminum chloride and aluminum

Ligand exchange reactions between phenanthrene or 9,10-dimethylphenanthrene with ferrocene effected in the presence of AlCl₃-Al were carried out under a variety of conditions. With phenanthrene (I), hydrogenation at the C-9 and C-10 positions could take place during the reaction and the cationic products obtained were the η⁶-phenanthrene-η⁵-cyclopentadienyliron and η⁶-9,10-dihydro-phenanthrene-η⁵-cyclopentadienyliron moncations (II and III), and the η⁶-phenanthrene-$\text{trans}$-$\text{bis}$-η⁵-cyclopentadienyliron and η⁶-9,10-dihydrophenanthrene-$\text{trans}$-$\text{bis}$-η⁵-cyclopentadienyliron dications (IV and V). With 9,10-dimethylphenanthrene (VI), reactions carried out in refluxing cyclohexane gave the non-hydrogenated η⁶-9,10-dimethylphenanthrene-η⁵-cyclopentadienyliron monocation (VII) and η⁶-9,10-dimethylphenanthrene-$\text{trans}$-$\text{bis}$-η⁵-cyclopentadienyliron dication (VIII). When higher temperatures were used in an attempt to promote hydrogenation, decomposition predominated and no cationic product could be obtained. These finding are discussed and contrasted with previous results obtained from similar reactions using anthracene or 9,10-dimethylanthracene.     

Reproducibility of glass open tubular columns in a production environment — Two years of experience

Summary The problems associated with the preparation of glass open tubular (capillary) columns are well documented in the literature. These problems are even more evident if column production is done on a routine basis, in a production environment. On the other hand, from the point of the user who wants to rely on a supplier, the reproducible quality of the columns is crucial. Here quality does not only mean efficiency but also refers to the reproducibility of the average liquid film thickness (capacity ratio) and the relative retention, as well as the tube treatment influencing the polarity of the column tube. In a paper published one year ago [1] our investigation concerning the reproducibility of the column manufacturing process was reported. The present paper continues this investigation. Four different columns will be considered: two types of OV-101 columns with thin and thick liquid film as well as columns prepared with Carbowax 20M and DEGS liquid phases. The consistency of their characteristics and efficiency will be investigated. Column characteristics include the capacity ratio which is directly related to the thickness of the liquid phase film. Column efficiency is investigated with help of the HETP and peak resolution. The effective and theoretical plate numbers are compared and the incorrectness of the assumption that the former is better suited for column testing is demonstrated. Relative retention reproducibility of even difficult peak pairs shows the consistency of column wall treatment. Finally, the consistency and performance of shorter columns obtained by the breaking of long columns will be discussed.Paper presented at the Second International Symposium on Glass Capillary Chromatography, Hindelang, Allgäu, Federal Republic of Germany, May 2–6, 1977.     

Synthese und Konfiguration von Methylestern der diastereomeren (±)-3-Amino-2,3-diarylpropansäuren,der (±)-3-Amino-2,3-diarylpropanole und ihrer Derivate

Zusammenfassung Durch Umsetzung von Hydramiden mit am aromatischen Ring m,p-dialkoxysubstituierten Arylessigsäureestern in Gegenwart von wasserfr. AlCl₃ entstehen Gemische aus Estern der (±)-erythro- und (±)-threo-3-Amino-2,3-diarylpropansäuren. Bei der Umsetzung von Piperonalhydramid mit dem Methylester der Homoveratrumsäure konnte lediglich daserythro-Diastereomere isoliert werden.Die diastereomeren Ester wurden zu den jeweiligen (±)-erythro- und (±)-threo-3-Amino-2,3-diaryl-1-propanolen reduziert, die als N,O-Dibenzoylderivate charakterisiert wurden. Ihre relativen Konfigurationen und die der zugehörigen Ester wurden auf Grund der IR-Spektren der diastereomeren Aminopropanole bestimmt. Die NMR-Spektren eines Diastereomerenpaares von Aminopropanolen bestätigen die ihnen chemisch zugeordneten Konfigurationen und ermöglichen den Nachweis auch ihrer bevorzugten Konformationen.

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Synthesis and configuration of methyl esters of the diastereomeric (±)-3-amino-2,3-diarylpropanoic acids, the (±)-3-amino-2,3-diaryl-1-propanols and their derivatives

Reaction of hydramides with m,p-dialkoxysubstituted arylacetates in the presence of anhydrous AlCl₃ generally leads to mixtures of the esters of the (±)-erythro- and (±)-threo-3-amino-2,3-diarylpropanoic acids. However, in the reaction of piperonal hydramide with methyl homoveratrate, only the correspondingerythro-diastereomer was obtained.Reduction of the diastereomeric esters gives the corresponding (±)-erythro- and (±)-threo-3-amino-2,3-diaryl-1-propanols, which can be characterized as N,O-dibenzoyl derivatives. Relative configurations of both alcohols and esters were determined by means of their IR spectra. Configurations were confirmed for one pair of diastereomeric amino alcohols by means of NMR spectra and preferred conformations deduced.

     

l-Leucanthemit als Inhaltsstoff von Gymnospermae

Zusammenfassung Die Bildung und das Vorkommen von Cycliten inThuja occidentalis wurden mit Hilfe der Methode der Photoassimilation in einer Atmosphäre von¹⁴CO₂ untersucht. Nebenmyo-Inosit, Sequoyit,d-chiro-Inosit undd-Pinit wurde auchl-Leucanthemit (l-1,2,4/3-Cyclohexentetrol), ein Cyclit, der bisher nur als Inhaltsstoff mehrerer Angiospermae bekannt ist, nachgewiesen. Das Vorkommen vonl-Leucanthemit konnte auch inPinus austriaca sichergestellt werden. Methoden zur Isolierung vonl-Leucanthemit ausThuja occidentalis wurden ausgearbeitet.

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The formation and the occurrence of cyclitols inThuja occidentalis has been studied, using the method of photoassimilation in an atmosphere of¹⁴CO₂. Besidesmyo-inositol, sequoyitol,d-chiro-inositol, andd-pinitol, alsol-leucanthemitol (l-1,2,4/3-cyclohexentetrol), a cyclitol which so far has only been found in Angiospermae, was identified. The occurrence ofl-leucanthemitol could also be established inPinus austriaca. Methods have been elaborated which permit the isolation ofl-leucanthemitol fromThuja occidentalis.

     

Photometric titrations. VIII

Summary Cadmium and zinc can be determined in one solution in the following manner. The sample is adjusted to p_H 9.4 with an ammonia-ammonium chloride buffer so that the total ammonia concentration is 0.01–0.03M. Zincon is added to attain a concentration of 0.06–0.18 mg/ml. The titration is performed photometrically at about 620 nm with EGTA as the titrant. The titration curve obtained shows two breaks which are related to the consecutive titration of cadmium and zinc. The influence of calcium impurities in the reagents used has been studied and a pre-titration method is proposed to deal with small calcium blanks. Calcium may also be added to the sample in order to obtain a titration curve which shows three breaks, which are related to the consecutive titration of cadmium, calcium, and zinc.

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Zusammenfassung Cadmium und Zink lassen sich nebeneinander in einer Lösung bestimmen. Man bringt die Probe durch Zusatz von Ammoniak-Ammoniumchlorid-Puffer auf p_H 9,4, so daß die totale Ammoniakkonzentration 0,01- bis 0,03-m ist. Pro ml werden 0,06 bis 0,18 mg Zincon zugesetzt, dann wird mit EGTA [Äthylenglykol-bis-(-aminoäthyläther)-N,N,N,N-tetraessigsäure] bei etwa 620 nm photometrisch titriert. Die Titrationskurve zeigt zwei Knickpunkte, die der aufeinanderfolgenden Titration von Cadmium und Zink entsprechen. Der Einfluß von Calcium-Verunreinigungen in den verwendeten Reagenzien wurde untersucht und eine Vortitration zur Bestimmung kleiner Calcium-Blindwerte vorgesehlagen. Man kann auch der Probe Calcium zusetzen und erhält dann eine Kurve mit drei Knickpunkten, entsprechend den aufeinanderfolgenden Titrationen von Cadmium, Calcium und Zink.

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Résumé On peut doser le cadmium et le zinc sur une seule solution de la manière suivante. On ajuste le p_H de l'échantillon à 9,4 par un tampon ammoniaque-chlorure d'ammonium de façon que la concentration totale en ammoniaque soit de 0,01–0,03M. On ajoute de la zincone jusqu'à l'obtention d'une concentration de 0,06–0,18 mg/ml. On effectue un dosage speetrophotométrique à 620 nm en utilisant l'EGTA comme agent titrant. La courbe de titrage montre deux points anguleux correspondant à la teneur en cadmium et en zinc. Après avoir étudié l'influence du calcium à l'état d'impuretés dans les réactifs utilisés, on propose une méthode de prétitrage pour faire les essais à blanc avec de petites quantités de calcium. On peut également ajouter du calcium à l'échantillon afin d'obtenir une courbe de titrage avec trois points anguleux relatifs aux titrages consécutifs du cadmium, du calcium et du zinc.

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See reference 1 for paper VII of the series.

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Dedicated to Prof.A. A. Benedetti- Pichler on the occasion of his 70th birthday.