Integration of parallel-operating quality systems

Since the 1980s, quality systems have become an essential element in successful companies and institutions. Today those systems are indispensable to fulfill the needs of the customers and last but not least the requirements of the society. Depending on the company's activities and fields of services, it is necessary to establish various quality systems. The Institut Fresenius (IF) Group runs a number of analytical laboratories and sampling groups. The whole group was accredited according to DIN EN 45001 in 1994. Good Laboratory Practice (GLP) was introduced in 1992 and was certified by the national authority. For certain customers, IF Group is also obliged to work according DIN EN ISO 9001 or GMP. A comparison of these systems with respect to their different priorities shows the possibility of integrating their rules into one comprehensive quality system. The IF Group has therefore installed a quality system operating in parallel. Multilocation accreditations and/or certifications are taking these efforts into account. The benefits are: high transparency of the system for the customers, auditors and personnel, a reduction of maintenance costs, and great flexibility to react to new standards. Could these activities lead to a new Integrated Management System?     

Photochemische Reaktionen. 83. Mitteilung. Verbindungen der 3,4-Dihydrojonon-Reihe als Modelle zur Photochemie γ, δ- bzw. δ, ϵ-ungesättigter Ketone und Aldehyde

Compounds of the 3,4-dihydro-ionone series as models for the photochemistry of γ, δ- and δ,?- unsaturated ketones and aldehydes . The photochemistry of γ, δ- and δ,?-unsaturated carbonyl compounds of the dihydro-ionone series has been studied, with special attention to the investigation of oxetane formation versus hydrogen abstraction. UV.-irradiation of the dihydro-β-ionone compounds with structure A ( 1 , 7 , 14 , 18 , 24 , 29 ) led to isomeric ethers with structures B ( 2 , 8 , 15 , 19 , 25 , 30 ), C ( 3 , 9 , 16 , 20 , 26 , 31 ) and D ( 4 , 21 , 27 ), isomeric bicyclic alcohols with structure E ( 5 , 10 , 17 , 22 , 28 ), and photoreduction products with structure F ( 6 , 11 , 12 , 13 ). Photolysis of dihydro-γ-ionone ( 32 ) gave a complex mixture containing fragmentation product 35 , hydrocarbon 36 , β-ambrinol ( 34 ), oxetane 33 , as well as dihydro-β-ionone ( 1 ) and three of its photoproducts ( 2 , 3 , 5 ). The dihydro-α-ionone compounds 37 and 40 gave mixtures of fragmentation products and the oxetanes 38 and 41 . Irradiation of the side-chain homologues 42 and 45 yielded 43 , which photo-cyclizes to 44 . In contrast, 3 , 4 -dihydro-3′,4′-dehydro-β-ionone ( 46 ) gave merely the isomeric open-chain triene-ketone 47 . The structures assigned to the ethers 2 , 3 , 33 , 38 and to the alcohols 5 , 10 , 13 could be confirmed by chemical reactions and mutual interconversions. The structure of the ether 21 had to be established by X-ray analysis, details of which are described. A novel intramolecular hydrogen transfer is involved in formation of ethers B . The photocyclization A → D probably proceeds by addition of the carbonyl-C atom to the double bond ( A → h ), followed by methyl (1 → 2)-shift ( h → i ). Process A → h may also be involved in formation of compounds of type C and E .     

Column switching in zone electrophoresis on a chip

This feasibility study deals with column switching in zone electrophoresis (ZE) separations on a column coupling (CC) chip. The column switching implemented into the ZE separations an on-chip sample clean up applicable for both the multicomponent and high salinity samples. In addition, complemented by different separation mechanisms in the coupled columns (channels), it provided benefits of two-dimensional separations. Properly timed column switching gave column-to-column transfers of the analytes, characterized by 99-102% recoveries, delivered to the second separation stage on the chip the analyte containing fractions contaminated only with minimum amounts of the matrix constituents. A diffusion driven transport of the matrix constituents to the second channel of the chip (due to direct contacts of the electrolyte solutions in the bifurcation region), representing 0.1-0.2% of the loaded sample constituents, was found to accompany the sample clean up performed on the CC chip. This source of potential disturbances to the separation in the second channel, however, is not detectable in a majority of practical situations. With respect to a 900 nl volume of the sample channel on the CC chip, the electric field and isotachophoresis (ITP) stackings were employed to minimize the injection dispersion in the separations and concentrate the analytes. Here, the column switching, removing a major part of the stacker from the separation system, provided a tool effective in a control of the destacking of analytes. Highly reproducible ZE separations as attained in this work also for the chip-to-chip and equipment-to-equipment frames can be ascribed, at least in part, to suppressions of electroosmotic and hydrodynamic flows of the solutions in which the separations were performed.     

Final state effects in the photoionization process

Different methods to take into account many body effects in photoionization processes are discussed. Numerical results are shown for some indirect methods, several approximations within the Green's function formalism, and for potential models. The suitability of the Green's function method for the investigation of satellite structure is considered.     

An Efficient Route to Emodic Amine and Analogous <Emphasis Type="Italic">O</Emphasis>-Methyl Protected Derivatives Starting from Emodin

Summary. Emodic amine could be synthesized in a five-step approach in excellent overall yield by following a modified Curtius rearrangement strategy, starting from the naturally occurring emodin. This unique emodin derived 6-amino substituted polyhydroxylated anthraquinone may serve as a promising synthon for a new class of amino functionalized photodynamically active hypericin derivatives. In addition, the partially O-methyl protected 6-amino- and 6-carboxy-anthraquinones could be synthesized in high yields via selective O-methyl ether cleavage from the corresponding tri-O-methyl derivatives.     

Biomimetic oxidation of plant protecting agents

The suitability of two in vitro oxidation systems as chemical models for the biological degradation of plant protecting agents has been investigated. As representative herbicides diclofop, fenoxaprop, isoproturon, linuron and monolinuron have been oxidised by two systems, the Fentons' reagent and the ascorbic acid oxidation system (AAOS) and the results compared to those of the known metabolic pathways of these compounds. The herbicides have been oxidised by Fentons' reagent (hydroxy radicals). The main products were isolated by preparative scale HPLC and identified with (1)H-NMR and MS. Some of the products have been identified by comparing their retention times and UV/Vis-spectra to those of standard compounds. Several products known from biological degradation are also found after chemical oxidation, however, notable differences between the two pathways have been observed, for instance in the case of diclofop. Oxidation by the AAOS leads to comparable results. Reaction rates for the oxidation with the AAOS have been studied and compared with data known from degradation studies of the herbicides in soil. Compounds which are slowly degraded in soil are oxidised more slowly in the biomimetic process than those with a fast degradation in soil.     

An ab initio calculation of the anisotropic hyperfine coupling constants in the low-lying vibronic levels of the X 2Pi electronic state of CCCH

The results of ab initio calculations of the vibronically averaged components of the anisotropic magnetic hyperfine tensor in the low-lying vibronic species of the X (2)Pi electronic state of CCCH and CCCD are reported. The electronically averaged hyperfine coupling constants for hydrogen and (13)C in (12)C (12)C (12)CH, (13)C (12)C (12)CH, (12)C (13)C (12)CH, (12)C (12)C (13)CH, and (12)C (12)C (12)CD are obtained as functions of two bending vibrational modes by the density functional theory method. The vibronic wave functions are calculated with help of a variational approach which takes into account the Renner-Teller effect and spin-orbit coupling. The results of the present study help to reliably interpret the experimental data previously published and predict the yet unobserved hyperfine structure in excited vibronic states of CCCH and CCCD.     

Palladium-catalyzed asymmetric addition of pronucleophiles to allenes

Simple additions are the most atom economic way to effect alkylations. The ability to effect the hydrocarbonation of allenes asymmetrically then becomes a highly efficient alkylation protocol. The first example of such a protocol involves the ability of a palladium(0) catalyst derived from palladium trifluoroacetate dimer and the bis-2-diphenylphosphinobenzamide of trans-1,2-diamininocyclohexane to catalyze additions to benzyloxyalkene. Various substituted Meldrum's acids including hydroxy Meldrum's acid react well in the presence of 1 mol % trifluoroacetic acid to give one regioisomer with ee's ranging from 82 to 99%. Switching to azlactones to access unusual quarternary amino acids requires somewhat more basic conditions. Thus, use of 2 mol % potassium alpha-butoxide and 20 mol % hippuric acid leads to a smooth reaction to produce a simple regiosomer. This nucleophile raises the question of facial selectivity with respect to both the nucleophile and the electrophile. Excellent diastereoselectivity (dr 13-20:1) and enantioselectivity (85-94% ee) are obtained. Thus, a new approach for asymmetric allylic alkylations of carbon pronucleophiles by simple additions provides a very efficient, more atom economic strategy for asymmetric C-C bond formation.     

The influence of the Jahn-Teller effect and of heteroligands on the reactivity of Cu2+

Experimentally hardly accessible Jahn-Teller inversions and the influence of heteroligands on the reactivity of Cu2+ are characterized by ab initio QM/MM MD simulations of Cu2+ ion and its amino complexes in water.     

C5-methylation of cytosine in B-DNA thermodynamically and kinetically stabilizes BI

We have examined the backbone dynamics of two alternating purine-pyrimidine dodecamers. One sequence consists of "pure" GC bases; the other one contains 5-methylcytosines. The effect of the methyl groups on the backbone substates BI/BII was investigated by means of molecular dynamics. The methylation influences, on one hand, the transition barrier between BI and BII and, on the other hand, the state of equilibrium. The kinetic consequences are an increase of the DeltaG of Gp5mC steps by 1.5 kcal/mol and a decrease of the DeltaG of 5mCpG steps by 0.8 kcal/mol (compared with the nonmethylated DNA). Thus, the additive group differentiates between the two occurring dinucleotide steps and renders the phosphate of the 5-methylcytosine more rigid, as proposed by experimental studies. The thermodynamic consequences are an increase of the DeltaG of Gp5mC steps by 1.1 kcal/mol and a decrease of the DeltaG of 5mCpG steps by 0.8 kcal/mol. The reason for this shift in equilibrium is still not completely clear on a molecular basis. But we can conclude that the indirect readout of DNA is influenced by methylation.