Mass-spectrometric identification of isomeric 1-benzoyl-2-azetidinones and 2-phenyl-4,5-dihydro-1,3-oxazin-6-ones

The mass spectra of isomeric 1-benzoyl-2-azetidinones and 2-phenyl-4,5-dihydro-1,3-oxazin-6-ones were analyzed. A more stable molecular ion and high intensities of the peaks of the ions formed from the molecular ion with the loss of ketene or a substituted ketene are characteristic for the former compounds, while low stability of the molecular ion and a higher probability of the loss of one of the groupings in the 4 position are characteristic for the latter compounds. Fragmentation schemes that are confirmed by the high-resolution mass spectra are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1627–1631, December, 1980.We sincerely thank E. Simova and C. Drey for providing us with samples of a number of the compounds.     

Microstructure and Texture Formation in Vacuum-deposited Silver Films

The role of the recystallization in the processes of microstructure and texture formation of silver films is compared for films: 1) deposited at high substrate temperatures (up to 720 K) and slowly cooled or quenched to room temperature; 2) deposited at room temperature and annealed at high temperatures. The grain growth distribution curves and the texture perfection are analysed. It is shown that the recrystallization processes taking place both during the slow cooling and during the annealing of the films lead to a formation of identical film structure with lower degree of texture perfection than in the case of quenched films.     

Development of tBu-phenyl Acetamide Appended Thiacalix[4]arene as “Turn-ON” Fluorescent Probe for Selective Recognition of Hg(II) Ions

Journal of Fluorescence - Herein, a novel N-(4-(tert-butyl)-phenyl)-2-chloroacetamide functionalized thiacalix[4]arene architecture, viz TCAN2PA has been synthesized and the sensing behaviour...     

The Lack of Lutein Accelerates the Extent of Light‐induced Bleaching of Photosynthetic Pigments in Thylakoid Membranes of Arabidopsis thaliana

The high light‐induced bleaching of photosynthetic pigments and the degradation of proteins of light‐harvesting complexes of PSI and PSII were investigated in isolated thylakoid membranes of Arabidopsis thaliana, wt and lutein‐deficient mutant lut2, with the aim of unraveling the role of lutein for the degree of bleaching and degradation. By the means of absorption spectroscopy and western blot analysis, we show that the lack of lutein leads to a higher extent of pigment photobleaching and protein degradation in mutant thylakoid membranes in comparison with wt. The highest extent of bleaching is suffered by chlorophyll a and carotenoids, while chlorophyll b is bleached in lut2 thylakoids during long periods at high illumination. The high light‐induced degradation of Lhca1, Lhcb2 proteins and PsbS was followed and it is shown that Lhca1 is more damaged than Lhcb2. The degradation of analyzed proteins is more pronounced in lut2 mutant thylakoid membranes. The lack of lutein influences the high light‐induced alterations in organization of pigment–protein complexes as revealed by 77 K fluorescence.     

Self-assembly properties of some chiral N-palmitoyl amino acid surfactants in aqueous solution

Various chiral N-palmitoyl amino acid surfactants (AAS) derived from methionine, proline, leucine, threonine, phenylalanine and phenylglycine were prepared and converted to their sodium salt. The properties of the aggregates formed in aqueous solution were studied for both the optically-active compounds and their racemic mixture. Characterization was made by surface tensiometry, fluorimetry, dynamic light scattering, circular dichroism (CD) and transmission electron microscopy. It appeared that most of the AAS studied in this work spontaneously formed different types of aggregates, including micrometer-sized aggregates. No significant difference could be found between the critical aggregation concentration (cac) value of pure enantiomers and that of the racemic forms. CD spectra did not reveal any aggregation-induced chirality.     

q-Difference intertwining operators and q-conformal invariant equations

We first recall a canonical procedure for the construction of the invariant differential operators and equations for arbitrary complex or real noncompact semisimple Lie groups. Then we present the application of this procedure to the case of quantum groups. In detail is given the construction of representations of the quantum algebra U _q (sl(n)) labelled by n–1 complex numbers and acting in the spaces of functions of n(n–1)/2 noncommuting variables, which generate a q-deformed SL(4) flag manifold. The conditions for reducibility of these representations and the procedure for the construction of the q-difference intertwining operators are given. Using these results for the case n=4 we propose infinite hierarchies of q-difference equations which are q-conformal invariant. The lowest member of one of these hierarchies are new q-Maxwell equations. We propose also new q-Minkowski spacetime which is part of a q-deformed SU(2,2) flag manifold.     

Synthese und Umwandlungen der N-substituierten 3-Aminopropansäuren, 5. Mitt.: Darstellung 2-substituierter 3,3-Diphenyl-3-benzoylamino-propansäuren

Zusammenfassung In Gegenwart von Lithiumamid in flüssigem Ammoniak lagern sich die -Wasserstoff enthaltenden t-Butylester aliphatischer Carbonsäure an das N-Benzoyldiphenylketimin an. Die dabei erhaltenen Ester gehen bei der Verseifung mit p-Toluolsulfonsäure in die jeweiligen 2-substituierten 3,3-Diphenyl-3-benzoylamino-propansäuren über. Neben den zu erwartenden Säuren geben die 2,2-disubstituierten Ester bei der Verseifung auch die entsprechenden -Lactame, darunter Spiro--lactame.

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Synthesis and transformations of N-substituted 3-aminopropanoic acids, V: preparation of 2-substituted 3,3-diphenyl-3-benzoylamino propanoic acids

t-Butyl esters of aliphatic carboxylic acids, containing -hydrogen, combine in the presence of LiNH₂ in liquid NH₃ with N-benzoyl-diphenylketimine; on saponification by p-toluenesulphonic acid, the resulting esters are converted into the resp. 2-substituted 3.3-diphenyl-3-benzoylamino-propanoic acids.Besides the expected acids, 2.2-disubstituted esters yield on saponification also the resp. -lactams; among these spiro--lactams were found.

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Mitt.: Mh. Chem.99, 1050 (1968).     

α-Amidoalkylation of CH-Acids by Means of N-(1,2,2,2-Tetrachloroethyl)-amides

The reaction of α-amidoalkylation of malonic and acetoacetic esters as well as tert. butylacetate, arylacetic acids and benzylcyanide with different N-(1,2,2,2-tetrachloroethyl)-amides was investigated and 2-substituted 3-acylamino-3-trichloromethyl propionic acids and esters were synthezised.     

Exotic bialgebras from 9 × 9 unitary braid matrices

The exotic bialgebras that arise from a 9 × 9 unitary braid matrix are constructed. The dual bialgebra of one of these exotic bialgebras is presented.