Elimination reactions of ions in the gas phase

The loss of water from the molecular ion of 2-adamantanol was investigated using specifically labelled deuterium derivatives, and, in particular that stereospecifically labelled in position 4. Water is lost predominantly in a stereospecific 1, 3 fashion by two clearly distinguishable mechanisms. Determination of metastable ion characteristics proved to be essential for drawing this distinction.     

Liquid-liquid extraction of cadmium(II) from aqueous thiocyanate solutions with liquid anion-exchangers

An investigation has been made on the system liquid anion-exchanger-Cd(II)-NCS⁻. The influence of the acidity and thiocyanate concentration of the aqueous phase on the extraction has been studied. Using various methods of analysis, it has been shown that the complex anion present in the organic extracts is Cd(NCS) ₄ ²⁻ . Details are given concerning the removal of traces of Zn(II) from Cd(II)-containing solutions, and the quantitative separation of Cd(II) from Cr(III).     

Mass spectometry of aralkyl compounds with a functional group—VI1: Mass spectra of 1-phenylethyanol-1, 2-phenylethanol-1 and 1-phenylpropanol-2

Mass spectra of 1-phenylethanol-1 and its analogues, specifically deuterated in the aliphatic chain, suggest that the [M? CH₃]⁺ ion is represented partly by an α-hydroxybenzyl fragment. Moreover, the molecular ion loses successively—after scrambling of all hydrogen atoms, except those of CH₃? a hydrogen atom and C₆H₆, generation the CH₃CO⁺ ion. Diffuse peaks, found in the spectra of of 2-phenylethanol-1 and its analogues, specifically deuterated in the aliphatic chain and in the phenyl ring, show that the molecular ion loses C₂H₄O, possibly via a four-center mechanism, after an exchange of aromatic and hydroxylic hydrogens. Mass spectra of 1-phenylpropanol-2 and its analogues, specifically, deuterated in the aliphatic chain, demonstrate that in the molecular ion exclusively the hydroxyl hydrogen atom is transferred to one of the ortho-positions of the phenyl ring via a McLafferty rearrangement, generating the [M ? C₂H₄O]⁺ ion. Furtherore, an eight-membered ring structure is proposed for the [M ? CH₃]⁺ ion to explain the loss of H₂O and C₂H₂O from this ion after an extensive scrambling of hydrogen atoms.     

Über 1, 5-Diphenyl-2, 3, 6, 7-tetrahydro-1H, 5H-pyrazolo[1, 2-a]pyrazole(2, 6-Diphenyl-1, 5-diazabicyclo[3, 3, 0]octane)

The synthesis of a 1, 5-diphenyl perhydro-pyrazolo-[1, 2-a] pyrazole (IV) (m. p. = 170–171°) by LiAlH₄-reduction of its 3, 7-dioxo derivative Va, one of the stereoisomers of V, is described. Va was obtained in small yield by the reaction of cinnamic acid with its hydrazide or with hydrazine. It proved to be identical with the compound obtained previously by interaction of cinnamic acid hydrazide with iodine which in the literature erroneously had been described as N, N′-dicinnamoyl hydrazine. This hydrazine now was obtained by bis-acylation of hydrazine with cinnamoyl chloride. In Va the extremely low NMR. absorption of the tertiary protons at ρ = 4,6 ppm is probably due to the spatial grouping with the proton situated in the deshielding region of the carbonyl group. Previously, another tertiary proton with a very low NMR. absorption at ρ = 4,85 ppm has been observed in the «bisimide M», the main criss-cross addition product of one mole benzaldazine and two moles of N-(n-butyl)-maleinimide. A stereostructure for bisimide M is now proposed, which is a hybrid between those of the bisimides L and H.     

Recherches dans la série des cyclitols XLII. Synthèses de cyclitols tout-cis dérivés du cyclopentane; préparation des cyclopentane-tétrol et - pentol tout-cis

All-cis cyclitols derived from cyclopentane have been prepared in two ways: (i) by LiAlH₄ reduction of all-cis epoxypolyos; (ii) by dimethyl sulfoxide treatment, in the presence of sodium hydrogencarbonate, of brominated derivatives containing a neighbouring benzoyloxy group; under these conditions, the halogen is replaced by a cis-oriented hydroxyl group. Thus all-cis cyclopentane-tetrol and -pentol have been prepared; their configuration has been confirmed by NMR. spectroscopy.     

Alkylierung ambidenter Heterocyclen-Anionen, 1. Mitt.: Über die Benzylierung des 4-Hydroxy-carbostyrils

Zusammenfassung 4-Hydroxy-carbostyrile (1a–c) werden mit Benzylchlorid inDMF bevorzugt zu den 4-Benzyloxy-carbostyrilen (2a–c) alkyliert. In wäßr. NaOH dagegen erhält man aus1a und1c als Hauptprodukt das 3,3-Dibenzyl-2,4-dioxo-1,2,3,4-tetrahydrochinolin (3).

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Alkylation of 4-hydroxy-quinol-2-ones (1a–c) with benzyl chloride inDMF in the presence of K₂CO₃ mainly gives the 4-benzylethers2a–c. However, carbon dialkylation takes place in aqueous NaOH and the main product of the reaction between benzylchloride and1a is 3.3-dibenzyl-2.4-dioxo-1.2.3.4-tetrahydro-quinoline3.

     

Alkylierung ambidenter Heterocyclen-Anionen, 2.Mitt.: Zur Alkylierung von 4-Hydroxy-carbostyrilen

Zusammenfassung Der Lösungsmitteleinfluß bei der Alkylierung von 4-Hydroxy-carbostyrilen (1–3) mit Äthyl- bzw. Methyljodid und Allylbromid wird untersucht. Während inDMF und Äthanol fast ausschließlich O-Alkylierung zu den 4-Alkoxy-carbostyrilen (4–7) eintritt, beobachtet man in wäßr. Alkalien auch die Bildung von C,C-dialkylierten Verbindungen (8–10). 3-Äthyl-4-hydroxy-carbostyril (2) reagiert leichter mit C₂H₅J zum 3,3-Diäthyl-2,4-dioxo-tetrahydrochinolin (8) als das unsubstit. 4-Hydroxy-carbostyril (1). Einige in der Literatur als 3,3-disubstit. 2,4-Dioxo-tetrahydrochinoline formulierte Verbindungen werden als Carbostyril-4-äther erkannt.

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The influence of the solvent in the alkylation reaction of 4-hydroxyquinol-2-ones (1–3) with various alkyl halogenides has been studied.DMF and ethanol favor high yields of O-alkylated products (4–7), in aqueous alkali, however, carbon alkylation successfully competes with O-alkylation, affording a substantial amount of 3.3-disubstituted 2.4-dioxo-tetrahydro-quinolines (8–10). The reexamination of a patent showed that some compounds previously described as 2.4-dioxo-tetrahydro-quinolines actually are carbostyril-4-ethers.

     

Die spezifische Wärme des Polyvinylchlorids

Zusammenfassung Die spezifische Wärme verschiedener handelsüblicher Polyvinylchlorid-Sorten (Suspensions- und Emulsions-PVC, schlagfestes PVC und ein Vinylchlorid-Vinylacetat-Copolymerisat) wurde im Temperaturbereich 20 (bzw. –50) bis 140 °C mit einem adiabatischen Kalorimeter gemessen. Besondere Aufmerksamkeit wurde dem Einfluß der thermischen Vorgeschichte gewidmet. Messungen an getemperten Proben ergaben — in Übereinstimmung mit den Ergebnissen anderer Autoren —einfache Kurvenzüge mit einem Steilanstieg der spezifischen Wärme im Einfriergebiet. Untersuchungen an abgeschreckten Proben ließen zu Beginn des Einfrierbereiches Minima der spezifischen Wärme infolge Enthalpierelaxation erkennen. Oberhalb des Einfrierbereichs zeigten sich Kristallisationserscheinungen mit Wärmetönungen von etwa –1,3 cal/g (exotherm). Hieraus wurde der kristalline Anteil des Polyvinylchlorids zu rund 3% abgeschätzt. Der Schmelzpunkt der PVC-Kristallite wurde differentialthermoanalytisch zu 156 bzw. 170 °C gefunden. Das schlagfeste PVC ließ das Schmelzen einer Spur Polyäthylen zwischen 102 und 125 °C erkennen. Die kalorimetrisch bestimmten Einfriertemperaturen stimmen mit dilatometrisch gemessenen — gleiche thermische Vorbehandlung vorausgesetzt — überein.

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Summary The specific heat of some commercially available samples of polyvinyl chloride (suspension PVC, emulsion PVC, high impact PVC, and a copolymerisate of vinylchloride and vinylacetate) was measured in the temperature range from 20 (or –50) to 140 °C, using an adiabatic calorimeter. Special attention was paid to the influence of thermal history of the samples. Investigations of annealed samples gave simple curves with a steep slope in the glass transition range, in agreement with the results of other authors. Measurements with samples quenched in ice water showed specific heat curves with a minimum at the beginning of the glass transition range caused by enthalpy relaxation. Above the glass transition range crystallization occurred accompanied by heat effects of about –1,3 cal/g (exothermal). From this the fraction of crystalline PVC was estimated to be about 3%. The melting point of the PVC crystallites as determined by differential thermal analysis was 156 or 170 °C. With high impact PVC the melting of traces of polyethylene was observed between 102 and 125 °C. The glass transition temperatures as determined by calorimetry agreed with those determined by dilatometric measurements, provided thermal pretreatment being equal in both cases.

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Mit 14 Abbildungen und 5 Tabellen