Characterization of Siegel cusp forms by the growth of their Fourier coefficients

We characterize all Siegel cusp forms of degree $n$ and large weight $k$ by the growth of their Fourier coefficients. More precisely we prove, among other related results, that if the Fourier coefficients of a modular form on the congruence subgroup $\Gamma _0^n(N)$ of square–free level $N$ satisfy the “Hecke bound” at the cusp $\infty $ , then it must be a cusp form, provided $k >2n+1$ .     

Recent progress in quantitative and high spatial resolution AES

Progress in high resolution Auger electron spectroscopy (HR-AES or scanning Auger microscopy, SAM) during the past few years is characterized by the use of efficient field emission electron sources, parallel detection capabilities and improved data acquisition, storage and processing, thus enhancing spatial resolution (to about 10 nm), signal to noise figure and quantification of elements in different chemical bonding states, e.g. by routinely using factor analysis. Optimized ion sputtering facilities, particularly sample rotation, enable depth profiling with high, depth independent resolution. The basic features of SAM are discussed with respect to EPMA (electron probe micro-analysis), emphasizing fundamental limitations and future developments.     

Facile Synthesis of 2-Benzylindoles

A wide range of 2-Benzylindoles 2 are conveniently and efficiently prepared by heating N-benzylindoles 1 in polyphosphoric acid. Mechanistic studies suggest an intramolecular rearrangement via the corresponding 3-benzyl intermediates.     

Ring‐Rearrangement Metathesis

Ring‐rearrangement metathesis (RRM) refers to the combination of several metathesis transformations into a domino process, in which an endocyclic double bond of a cycloolefin reacts with an exocyclic alkene. RRM has proven to be a powerful method for the rapid construction of complex structures. The extension of the basic ring‐opening–ring‐closing metathesis process by further metathesis steps as well as an examination of the driving forces, limits, scope, recent advantages, and future perspectives of these domino sequences is presented with various examples, thus reflecting the high efficiency and utility of RRM in organic synthesis.     

1,25-Dihydroxyvitamin D3 and analogues protect primary human keratinocytes against UVB-induced DNA damage

Exposure to UVB irradiation is a major risk factor for the development of skin cancer. Therefore, it is important to identify agents that can offer protection against UVB-caused damage. Photocarcinogenesis is caused largely by mutations at sites of incorrectly repaired DNA photoproducts, of which the most common are the cyclobutane pyrimidine dimers (CPDs). In this study, we demonstrated that 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] protects primary human keratinocytes against the induction of CPDs by UVB. This protection required pharmacologic doses 1,25(OH)2D3 and an incubation period of at least 8 h before irradiation. Furthermore, we provided arguments indicating that the anti-proliferative capacity of 1,25(OH)2D3 underlies its protective effect against UVB-induced DNA damage. Finally, we showed that 19-nor-14-epi-23-yne-1,25(OH)2D3 (TX 522) and 19-nor-14,20-bisepi-23-yne-1,25(OH)2D3 (TX 527), two low-calcemic analogues of 1,25(OH)2D3, were even 100 times more potent than the parent molecule in inhibiting UVB-caused DNA damage. These molecules are therefore promising candidates for the chemoprevention of UVB-induced skin cancer.     

Metal-Free Twofold Electrochemical C−H Amination of Activated Arenes: Application to Medicinally Relevant Precursor Synthesis

The efficient production of many medicinally or synthetically important starting materials suffers from wasteful or toxic precursors for the synthesis. In particular, the aromatic non-protected primary amine function represents a versatile synthetic precursor, but its synthesis typically requires toxic oxidizing agents and transition metal catalysts. The twofold electrochemical amination of activated benzene derivatives via Zincke intermediates provides an alternative sustainable strategy for the formation of new C−N bonds of high synthetic value. As a proof of concept, we use our approach to generate a benzoxazinone scaffold that gained attention as a starting structure against castrate-resistant prostate cancer. Further improvement of the structure led to significantly increased cancer cell line toxicity. Thus, exploiting environmentally benign electrooxidation, we present a new versatile and powerful method based on direct C−H activation that is applicable for example the production of medicinally relevant compounds.     

Mass spectrometric profiling of Bacillus cereus strains and quantitation of the emetic toxin cereulide by means of stable isotope dilution analysis and HEp-2 bioassay

A fast and robust high-throughput ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC–TOF MS) profiling method was developed and successfully applied to discriminate a total of 78 Bacillus cereus strains into no/low, medium and high producers of the emetic toxin cereulide. The data obtained by UPLC–TOF MS profiling were confirmed by absolute quantitation of cereulide in selected samples by means of high-performance liquid chromatography with tandem mass spectrometry (HPLC–MS/MS) and stable isotope dilution assay (SIDA). Interestingly, the B. cereus strains isolated from four vomit samples and five faeces samples from patients showing symptoms of intoxication were among the group of medium or high producers. Comparison of HEp-2 bioassay data with those determined by means of mass spectrometry showed differences, most likely because the HEp-2 bioassay is based on the toxic action of cereulide towards mitochondria of eukaryotic cells rather than on a direct measurement of the toxin. In conclusion, the UPLC–electrospray ionization (ESI)–TOF MS and the HPLC–ESI–MS/MS–SIDA analyses seem to be promising tools for the robust high-throughput analysis of cereulide in B. cereus cultures, foods and other biological samples.

Syntheses and characterization of two dioxygen-reactive dinuclear macrocyclic schiff-base copper(I) complexes

The dinuclear copper(I) complex [Cu(2)L(1)(CH(3)CN)(2)](ClO(4))(2) (1, L(1) = 3,6,9,17,20,23-hexaazatricyclo[23.3.1.1]triaconta-1(29),2,9,11(30),12(13),14,16,23,25,27-decaene) has been structurally characterized. As previously described, intramolecular ligand hydroxylation (at the aromatic ring) was observed when 1 was reacted with dioxygen. A stopped-flow analysis of the reaction of 1 with dioxygen under different conditions did not allow a "dioxygen intermediate" to be spectroscopically detected. Detailed NMR and electrochemical data on 1 are also presented and evaluated for the first time. No copper(II) complexes of L(1) could be characterized due to hydrolysis of the compounds. In contrast, complex 2-differing from 1 only in an increase in the size of the chelate rings-did not undergo intramolecular hydroxylation when it was oxidized. The crystal structure of 2 is also described.     

Zur Kenntnis der Halogensauerstoffverbindungm

Zusammenfassung Es wurde die Kinetik der Bromatbildungsreaktion nach 3 Br₃+6 OH=8 Br+BrO₃+3 H₂O, beziehungsweise 3 Br₂+6 OH=5 Br+BrO₃+3 H₂O untersucht und gefunden, daß die Geschwindigkeit der Bromatbildung mit den Konzentrationen von Brom und Hydroxylion steigt und mit zunehmender Bromionkonzentration abnimmt. Die Werte der Potenzexponenten der Konzentrationen variieren mit der Geschwindigkeit. Neutralsalze verzögern.Es wurde ferner für die rasche Reaktion das Zeitgesetz –d[Br₃]/d=k ₁[OH]/[Br]³[Br₃]², beziehungsweise –d[Br₂]/d=k₁[OH]/[Br][Br₂]² und für die langsame Reaktion das Zeitgesetz –d[Br₃]/d=k ₂[OH]⁴/[Br]⁷[Br₃]³, beziehungsweise –d[Br₂]/d=k₂[OH]⁴/[Br]⁴[Br₂]³ wahrscheinlich gemacht. Der Temperaturkoeffizient der in einer Monophosphat-Biphosphatlösung gemessenen langsamen Reaktion ist von der Größenordnung 17.Aus den Geschwindigkeitskoeffizienten der raschen Reaktion und dem der Reaktion HBrO+OH BrO₃ läßt sich das Brom-Hypobromitgleichgewicht und aus den Koeffizienten der langsamen Reaktion und dem der Reaktion BrO₃+Br+H^. Br₂ das Brom-Bromatgleichgewicht berechnen.Vgl. die vorhergehende Arbeit.