Die massenspektrometrische Fragmentierung von NiII-Chelaten mit O-, N-, S-, Se-Donoratomen

Mass Spectrometric Fragmentation of Ni^II Chelates with O-, N-, S-, Se-Donor Atoms The mass spectra of 6Ni^II chelates having the same substituents but different donor atoms (sequence of ligand atoms ? C(X)? NH? C(Y)? ; X, Y = O, S, Se, NH; see formula (1)) are discussed. The fragmentation pattern of the (thio)benzoyl(thio, seleno)ureas are characterized by the abstraction of S or Se atoms. The appearence of small neutral molecules seems to be typical for the fragmentation of all complexes. The mass spectrum of the Ni^II chelate having a NiS₂Se₂ coordination sphere shows no molecular ion peak. The contents of molecular ions in the total ion stream correlates with the stability of the complexes.     

Synthese von ω-(5-Oxo-1-cyclopentenyl)alkansäure-methylestern aus 2-Nitrocycloalkanonen

Synthesis of Methyl ω-(5-Oxo-1-cyclopentenyl)alkanoates Starting from 2-Nitrocycloalkanones A convenient synthesis of methyl ω-(5-oxo-1-cyclopentenyl)alkanoates 1 is described. 2-Nitrocycloalkanones 2 are converted to 2-(3,3-dimethoxypropy1)-2-nitrocycloalkanones 4 . Treatment of 4 with MeOH/MeONa led to the ring-opened nitronates 5 which underwent a Nef reaction to form the corresponding oxo derivatives 6 . Partial hydrolysis of followed by base-catalyzed aldol reaction gave the desired products in high yields.     

Solubility of Solid 1-Hexene and 2-Methylpentane in Liquid Argon and Nitrogen at the Standard Boiling Points of the Solvents

The solubilities of solid 1-hexene and 2-methylpentane in liquid argon at a temperature of 87.3 K and in liquid nitrogen at 77.4 K have been measured by the filtration method. The hydrocarbon contents in solutions were determined using gas chromatography. The experimental value of the mole fraction solubility of solid 1-hexene in liquid argon at 87.3 K is (3.87 ± 0.74) × 10^-7 and (7.94 ± 2.47) × 10^-9 in liquid nitrogen at 77.4 K. The experimental value of the mole fraction solubility of solid 2-methylpentane in liquid argon at 87.3 K is (1.45 ± 0.36) × 10^-5 and (6.80 ± 2.16) × 10^-8 in liquid nitrogen at 77.4 K. The Preston–Prausnitz method was used for calculation of the solubilities of solid hydrocarbons in liquid argon in the temperature range 84.0–110.0 K and in liquid nitrogen from 64.0 to 90.0 K. The solvent–solute interaction parameters 1₁₂ were also calculated. At 90.0 K, liquid argon is a better solvent for solid 1-hexene and 2-methylpentane than is liquid nitrogen.     

Shapley-Based Estimation of Company Value—Concept,Algorithms and Parameters

The aim of the article is to propose a new method of valuation of a company, considering its ownership relations with other companies. For this purpose, the concept of the Shapley value from cooperative game theory is used as the basis for assessing such dependent companies. The paper presents proposals for Shapley value calculation algorithms for our model. We expand our model by discussing personal relations in addition to ownership relations and point out how intuitionistic fuzzy sets may be helpful in this context. As a result, we propose two new expanded models. In the first probabilistic model, we apply Pearson’s correlation coefficient, in the second, we use a correlation coefficient between intuitionistic fuzzy sets to determine the personal relationships. Finally, we present and interpret results for a real-world economic network with 17 companies.     

An Improved Synthesis of Elvitegravir

An improved process for the active pharmaceutical ingredient of a new HIV integrase inhibitor elvitegravir ( 1 ) has been developed. It starts from commercially available 2,4‐dimethoxyacetophenone, which is selectively halogenated into the position 5. The 5‐halo acetophenones are condensed with dialkyl carbonates to give the corresponding benzoylacetates. Their treatment with N,N‐dimethylformamide dimethyl acetal followed by (S)‐valinol then provided the corresponding intermediate benzoyl acrylates. Cyclization to the required 1,4‐dihydroquinolin‐4‐oxo derivatives by aromatic nucleophilic substitution of the 2‐methoxy group was achieved by treatment with N,O‐bis(trimethylsilyl)‐acetamide, which also protected the OH group as the trimethylsilyl derivative. Finally, the Negishi coupling with 2‐fluoro‐3‐chlorobenzylzinc bromide and the following hydrolysis provided elvitegravir ( 1 ). The preferred variant, the seven‐step procedure starting from 2,4‐dimethoxyacetophenone, provides elvitegravir in 29.3% yield.     

Feste Brennstoffe

Ohne Zusammenfassung     

Determination of hydroxyaromatic compounds in complex mixtures by tandem mass spectrometry

Derivatization of alkylated hydroxyaromatics with N-methyl-bis(trifluoracetamide) is used for a rapid screening for alkylated hydroxyaromatic compounds in complex mixtures by tandem mass spectrometry. Applications are based on a detailed investigation of the fragmentation reactions of derivatized alkylated phenols, 2,3-dihydroindenols, indenols, 1,2,3,4-terrahydronaphtbols and naphthols. As shown by daughter-ion mass spectra obtained in different field-free regions of a BEQQ-instrument, the loss of CF₃COOH, CF₃CO˙ or CF₃COO^˙, respectively, is common for the compounds studied and can be used for their detection by means of neutral mass loss scans.     

Quantitative analysis of DNA methylation in chronic lymphocytic leukemia patients

Changes in the genomic DNA methylation level have been found to be closely associated with tumorigenesis. In order to analyze the relation of aberrant DNA methylation to clinical and biological risk factors, we have determined the cytosine methylation level of 81 patients diagnosed with chronic lymphocytic leukemia (CLL). The analysis was based on DNA hydrolysis followed by derivatization of the 2'-desoxyribonucleoside-3'-monophosphates with BODIPY FL EDA. Derivatives were separated by micellar electrokinetic chromatography, and laser-induced fluorescence was used for detection. We analyzed potential correlations between DNA methylation levels and numerous patient parameters, including clinical observations and biological data. As a result, we observed a significant correlation with the immunoglobulin variable heavy chain gene (VH) mutation status. This factor has been repeatedly proposed as a reliable prognostic marker for CLL, which suggests that the methylation level might be a valuable factor in determining the prognostic outcome of CLL. We are now in the process of refining our method to broaden its application potential. In this context, we show here that the oxidation of the fluorescence marker in the samples and the evaporation of methanol in the electrolytes can be prevented by a film of paraffin oil. In summary, our results thus establish capillary electrophoresis as a valuable tool for analyzing the DNA methylation status of clinical samples.     

Beiträge zur Entwicklung psychotroper Stoffe, 4. Mitt.: Diphenylamin-Derivate mit piperidylsubstituierten Seitenketten

Zusammenfassung Es werden Derivate des Carbazols, des Phenothiazins, des Phenoxazins, des Iminodibenzyls und des Iminostilbens beschrieben, bei denen der Stickstoff der erwähnten Heterocyclen über eine n-Propylenkette mit dem Stickstoff von Piperidin-Derivaten verbunden ist. Der Piperidylrest ist entweder unsubstituiert oder in 4-Stellung mit der Oxogruppe (einschließlich ringförmiger Ketalderivate), der Hydroxylgruppe, der Alkoxygruppe, der -Hydroxyäthylgruppe oder mit der Aminogruppe substituiert. M. Thiel undK. Stach, 3. Mitt.: Mh. Chem.93, 1080 (1962).