Template synthesis in the nickel(II)–thiocarbohydrazide–propanone triple system

The complexing process proceeding in the Ni^II–thiocarbohydrazide (H₂N–H–NC(=S)–NH–NH₂)–propanone triple system in EtOH solution and nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix has been studied. It has been found that in the first case, template synthesis leading, as a minimum, to formation of three coordination compounds of Ni^II with (N,N,S,S)-donor tetradentate ligands having NiL¹, NiL² and NiL³compositions where L¹ is 4,6,6-trimethyl-2,3,7,8-tetraazanonen-3-di(thiohydrazide)-1,9, L² is 4,6,6,12-tetrametyl-1,9-dithio-2,3,7,8,10,11-hexaazatridekadien-3,11-hydrazide-1 and L³ is 2,8,10,10,16-pentamethyl-5,13-dithio-3,4,6,7,11,12,14,15-octaazaheptadekatrien-2,7,15 is observed, whereas in the gelatin-immobilized matrix, a complexing process in the system considered does not occur.     

Beiträge zur quantitativen Dünnschichtchromatographie. V

Zusammenfassung Eine dünnschichtchromatographische Trennung des Wismuts von einem Überschuß an Metallen der Schwefelwasserstoffgruppe wurde beschrieben. Als Laufmittel dient ein Gemisch von tert.-Butanol, Salzsäure und Wasser. Nach Absaugen der Sorptionsschicht wird das Wismut mit MDCM spektralphotometrisch bestimmt. Standardabweichung und Varianz des Verfahrens werden angegeben.

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Summary A thin layer Chromatographic separation of the bismuth from an excess of metal ions of the hydrogen sulfide group is described. A mixture of tert. butanol, hydrochloric acid and water serves as mobile phase. After sucking off the sorption layer, the bismuth is determined spectrophotometrically with MDCM. The standard deviation and the variance of the procedure is given.

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Résumé On décrit une séparation par Chromatographie en couche mince du bismuth de métaux en excès du groupe de l'hydrogène sulfuré. On utilise comme éluant un mélange de butanol tert., d'acide chlorhydrique et d'eau. Après aspiration de la couche de sorption, on dose par spectrophotométrie le bismuth par le MDCM. On communique l'écart-type et le coefficient de variation du procédé.

     

Distribution of counterions in the double layer around a cylindrical polyion

The modified Poisson-Boltzmann (MPB) equation, and the Monte Carlo (MC) method, were applied to the cell model of a polyelectrolyte solution in order to calculate the distribution of counterions around a cylindrical polyion. Both methods suggest stronger binding of counterions to the polyion than predicted by the ordinary Poisson-Boltzmann (PB) equation. The inclusion of counterion-counterion correlation being neglected in the PB equation, leads to a better agreement of the calculated osmotic coefficients with those measured.     

Direct flame-photometric determination of calcium in soil and plant extracts,water and serum with special reference to sodium,potassium and phosphate interference

An investigation of the possibilities for the direct determination of calcium with a single-cell filter flame photometer, without preliminary separation as oxalate, led to the following conclusions:Calibration curves for 100 p.p.m. of calcium are rectilinear.Sodium causes an appreciable positive error.The error due to potassium interference is relatively much smaller than that due to sodium. Up to a certain concentration it is positive and increases with the concentration, then the emission seems to be gradually depressed and the error finally becomes negative.Phosphates cause a very significant negative error, which tends to be asymptotic. The “radiation buffer” method of correction is not practical here because the max. error is too high (—92.5%).Except for extreme cases, calcium can be determined by direct spraying, without preliminary separation as oxalate: (a) in drinking and irrigation water, correction being necessary only for sodium interference, (b) in soil extracts, correcting only for phosphate effects, (c) in normal blood sera, without clinically significant corrections at 1+3 dilution.Owing to the large variations in the contents of Na, K and PO₄^-3 in plants, calcium cannot be determined in plant-ash extracts without preliminary separation as oxalate. This applies also to abnormal sera, although there the variations in Na and PO₄^-3 content are not so large.     

Synthesen von Heterocyclen, 45. Mitt.: Über eine Synthese von substituierten Barbitursäuren

Zusammenfassung Kürzlich wurde in einer Publikation vonA. K. Bose undS. Garratt über eine neue Synthese von substituierten Barbitursäuren aus Malonsäuren und substituierten Malonsäuren mit Carbodiimiden berichtet. Hierdurch sehen wir uns veranlaßt, über unsere bisherigen Ergebnisse im Rahmen ähnlicher Untersuchungen kurz zu berichten.     

Enantioselective reduction of ketophosphonates using chiral acid adducts with sodium borohydride

A method for asymmetric reduction of α-and β-ketophosphonates using a chiral complex prepared from sodium borohydride and D-or L-tartaric acid is developed. Reduction of α-or β-ketophosphonates by these reagents led to formation of corresponding (S)-or (R)-hydroxyphosphonates. Reduction of chiral di(1R,2S,5R)-menthylketophosphonates by the chiral complex NaBH₄/(R,R)-tartaric acid due to the dual compliant asymmetric induction resulted in increased stereoselectivity of the reaction and led to formation of the hydroxyphosphonates with ee 90% or higher. On the other hand, reduction of di(1R,2S,5R)-methylketophosphonates by the chiral complex NaBH₄/(S,S)-tartaric acid proceeded as non-compliant dual asymmetric induction and resulted in decreased reaction stereoselectivity leading to formation of hydroxyphosphonates with ～45–60% ee. The developed methodology was applied to the synthesis of (R)-phosphocarnitine in multigram amounts.     

Influence of a Surface Microheterogeneity on the Disjoining Pressure of Adsorbed Lennard–Jones Fluid. Computer Simulation

Computer simulation of the adsorption of Lennard–Jones fluid in slitlike micropores with structured walls was performed by the Monte Carlo and molecular dynamic methods. The influence of pore width, temperature, pressure, and surface structure on the disjoining pressure was considered. Structural and energy characteristics of the surface affect significantly the value of the disjoining pressure. Among the surface structural characteristics, the important role is played by the number and localization of vacancy-type defects.     

(2-Vinyloxyethyl)hydrazines

Reaction of hydrazine hydrate with 2-chloroethyl vinyl ether afforded (2-vinyloxyethyl)hydrazine and 1,1-bis(2-vinyloxyethyl)hydrazine in 20-38% yield.     

Darstellung und thermische Zersetzung von Lithiumcyanuraten Eine einfache Methode zur Gewinnung von wasserfreiem Lithiumcyanat

Zusammenfassung Die Darstellung von Mono-, Di- und Tri-Lithiumcyanurat durch Umsetzung von Cyanursäure mit LiOH bzw. Li₂CO₃ in hochsiedenden Alkoholen und durch lösungsmittelfreie Festkörperreaktion wird beschrieben. Die Festkörperreaktionen werden mit Hilfe thermoanalytischer Methoden untersucht. Die Reaktion mit LiOH erfolgt in zwei Schritten und ergibt bei 400°C. Trilithium-cyanurat. Unter denselben Bedingungen wird mit Li₂CO₃ nur Dilithium-cyanurat gebildet. Die Thermolyse von Trilithium-cyanurat bei 550°C liefert in hoher Ausbeute Lithiumcyanat und stellt somit eine einfache Methode zur Darstellung dieser Verbindung in wasserfreier Form dar.

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Formation and thermolysis of lithium cyanurates (a simple preparation of anhydrous lithium cyanate)

The formation of mono-, di- and tri-lithium cyanurate by reaction of LiOH or Li₂CO₃ with cyanuric acid has been investigated as a solid state reaction and by using high boiling alcohols as reaction medium. For investigating the solid state reactions thermoanalytical methods were used. The reaction with LiOH proceeds in two steps yielding trilithium cyanurate at 400°C. Under the same conditions only dilithium cyanurate is formed by reaction with Li₂CO₃. Lithium cyanate is obtained in high yields by thermolysis of trilithium cyanurate at 550°C. This procedure is therefore a simple method in synthesizing pure anhydrous lithium cyanate.

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Mit 3 Abbildungen

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Herrn Univ.-Prof. Dr.O. Kratky zum 70. Geburtstag gewidmet.     

Synthesis of 1, 2-diazabicyclo [4.4.0] decane and its derivatives

A new heterocyclic system, 1, 2-diazabicyclo [4.4.0] decane is synthesized, starting from-(piperidyl-2) propionic acid. The latter is converted to-(1-nitrosopiperidyl-2)-propionic acid, and thence, via-(1-aminopiperidyl-2) propionic acid, to 3-keto-1, 2-diazabicyclo [4.4.0] decane. Derivatives of 1, 2-diazabicyclo [4.4.0] decane with a substituent at position 2 are prepared.