Aminomethylierung von Thiophosphorsäuredialkylester-, Phosphon- bzw. Thiophosphonsäurealkylesteramiden,Phosphon- bzw. Thiophosphonsäurediamiden und Diphenylthiophosphinsäureamid

Aminomethylation of Phosphoro-, Phosphono-, Phosphinoamidoates and -amidothioates Dialkylphosphoroamidates, alkyl-phosphonoamidates and phosphonoamidothioates react with C₂H₅O? CH₂? NR₂ and HCOH/HNR₂, respectively, as like as a N-aminomethylation forming the corresponding derivatives of the general formula R₂P(X)? NR′? CH₂? NR″₂? R = alkoxy, alkyl, aryl; R′ = H, alkyl; X = O, S; R″ = alkyl, cycloalkyl —. Under the same conditions phosphonodiamidoates and phosphonodiamidothioates yield RP(X)-[NR′? CH₂? NR″₂]₂ or RP(X)? NHR′? (NR′? CH₂? NR″₂) only. These compounds are not formed by interactions of RP(X)(NR′? CH₂OH)₂ with sec. amines. The aminomethylation of (C₆H₅)₂P(S)NH₂ gives unexceptional [(C₆H₅)₂P(S)]₂N? CH₂? NR′₂. The i.r. and ¹H-n.m.r. data of the prepared compounds, which can't be distilled mostly, are discussed.     

New insoluble surfactant systems as aids in catalysis. A convenient method for nonbonded immobilization of catalytically active transition metal complexes

New insoluble surface-active substances are described here for the first time. They were synthesized by esterification of the surfactants sodium 11-hydroxy-undecane-1-sulfonate or dodeca-ethylene glycol monododecyl ether with an aliphatic amino acyl chloride, reaction of the amino group containing ester with the bifunctional reagent 3-(triethoxysilyl) propyl isocyanate, and anchoring the products obtained on silica 100 under mild conditions.The surfactants thus immobilized showed a micellar effect, as proved by their influence on reaction rate and selectivity in the enantioselective hydrogenation of methyl (Z)--acetamido-cinnamate to methylN-acetyl-phenylalaninate (R) by means of an optically active rhodium complex in water.The systems were compared with an inorganic ion exchanger with dodecyl sulfate counterions and with sodium dodecyl sulfate adsorbed to alumina. The influence of the immobilized surfactants on reaction rate and selectivity appeared to be dependent on the mobility of the hydrophobic chains.     

Optode membrane for continuous measurement of silver ions

An optical sensor (optode) membrane for continuous monitoring of silver ion is presented. It is composed of plasticized poly(vinyl chloride) (PVC), a silver-sensitive chromo-ionophore, and a lipophilic borate salt acting as an anionic site. The membrane selectively responds to silver ion in the concentration range from 50 M to 10 mM, giving a reversible colour change from blue to pink, with response times of the order of 2 min. The acridinium dye acts as both the recognition element and the chromo—ionophore. Its long-wave absorption band is at around 680 nm, which makes it compatible with existing LED light sources and diode lasers. A lipophilic octadecyl side chain renders it highly lipophilic and this prevents its leakage out of the PVC membrane. Hence, the operational lifetime exceeds 1 week, without any changes in the work function.     

Studies on the Synthesis of Trisaccharide Analogues of the Antibiotic Moenomycin A

A new approach for the synthesis of moenomycin trisaccharide analogues is reported in which three monosaccharide building blocks are used and allows the introduction of different substituents at the 6‐position of unit E (Scheme 2). Furthermore, a new procedure for the introduction and manipulation of unit F is described (Scheme 3).     

An unequivocal1H NMR structural assignment of TOX8 and TOX9, the two most abundant toxaphene congeners in marine mammals

The structure of the two most abundant toxaphene congeners has unequivocally been established by 500 MHz¹H NMR spectroscopy as 2-endo,3-exo,5-endo, 6-exo,8,8,9,10,10-nonachlorobornane (TOX9) and as 2-endo,3-exo,5-endo,6-exo,8,8,10,10-octachlorobornane (TOX8). Semiempirical calculations (AM1 and PM3-MNDO) were carried out for both structures. The distance information found by nuclear Overhauser enhancement (NOE) for the protons is in agreement with the energy minimized AM1 and PM3-MNDO structures. For these definitively established NMR data for TOX8 and TOX9, together with literature data for other toxaphene isolates, a set of rules has been derived for¹H chemical shifts in polychlorinated bornane structures. A set of rules is also proposed for assigning systematical nomenclature to NMR-derived polychloro bornane structures.     

Determination of polychlorinated dibenzofuran (PCDF) and dibenzo-p-dioxin (PCDD) levels and isomer patterns in fish, crustacea, mussel and sediment samples from a fjord region polluted by Mg-production

Summary Isomer-specific determination of polychlorinated dibenzofurans (PCDF) and dibenzo-p-dioxins (PCDD) was carried out in 37 samples of different fish species, crustaea and mussel from a fjord area contaminated by waste water from a Mg-factory. In addition 6 sediment samples were analysed. The tetra- and pentachlorodibenzofuran isomer pattern of the Mg-process is very characteristic and dominated by isomers with chlorine in the positions 1,2,3,7 and/or 8. Very similar patterns were found in sediment, crustacea and mussel samples up to 15 km from the factory. Nearly all isomers were present in crab, shrimp and mussel while fish samples contained mainly 2,3,7,8-substituted congeners. The isomer distributions and concentration levels for different species and tissues with high and low fat content are presented. The applied analysis techniques and the quality assurance procedure as well as practical problems are described in detail. The found levels varied between low ppt- and high ppb-levels for single isomers.

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Bestimmung von polychlorierten Dibenzofuranen (PCDF) und Dibenzo-p-dioxinen (PCDD) und deren Isomerenverteilung in Fisch, Crustaceen, Muscheln und Sedimenten einer durch Mg-Produktion verunreinigten Fjordregion

     

Gas chromatographic separation of atropisomeric polychlorinated biphenyls and methylsulfonylated derivatives with partially ethylated γ-cyclodextrin

Summary A capillary containing partially ethylated octakis(2,3,6-tri-O-ethyl)-γ-cyclodextrin diluted in PS 086 separated the atropisomeric polychlorinated biphenyls (PCBs) 45, 84, 131, 136, 171, 176 and 197. In addition, PCBs methylsulfonylated in position 3 such as 3-MeSO₂-PCB 95, 3-MeSO₂-PCB 132, 3-MeSO₂-PCB 149 and 3-MeSO₂-PCB 174 could also be split into their atropisomers. The corresponding 4-MeSO₂-PCB atropisomers could not be separated.     

Preparation and Synthetic Utility of 1-Trimethylsiloxyalkyl-bis(trimethylsilyl)silanes, (Me3Si)2SiH–C(OSiMe3)R1R2

1-Trimethylsiloxyalkyl-bis(trimethylsilyl)silanes ( 5 ), obtained by a base induced isomerization of easily accessable 1-hydroxyalkyl-tris(trimethylsilyl)silanes ( 1 ) were hydrolized to give 1-hydroxyalkyl-bis(trimethylsilyl)silanes ( 6 ), which in presence of sodium hydride underwent a further 1,3-Si,O-trimethylsilyl migration resulting in the formation of 1-trimethylsiloxyalkyl-disilanes Me₃SiSiH₂–C(OSiMe₃)R¹R² ( 7 ). Under acidic conditions, the alkoxysilanes 5 isomerized in a Me₃Si/OSiMe₃ exchange under formation of the 1-trimethylsilylalkyldisiloxanes 10 , which were hydrolyzed affording the silanols 11 . Chlorination of the H-silanes 5 with CCl₄ gave the chlorosilanes 12 , which underwent rapid thermal isomerizations to give via the 1-chloroalkyldisiloxanes 13 the 1-trimethylsilylalkyl-chlorodisiloxanes 15 . Hydrolysis of 12 or 15 , resp., finally afforded the 1-trimethylsilylalkyl-silanediols 18 . Possible mechanisms of the various isomerization processes are discussed. The structures of the products described were elucidated by full spectral analyses. For 18 a the results of an X-ray structural analysis are given.     

Copolymerization of 1,3-butadiene and styrene with a neodymium catalyst

Homo- and copolymerization of butadiene and styrene in the presence of the catalyst system Nd(octanoate)₃/CCl₄/Al(iBu)₃ (iBu: isobutyl) were investigated at 60°C in heptane as solvent. The initiating catalyst system is very effective in the polymerization of butadiene. However, the presented copolymerization of butadiene and styrene is only practicable when using a special addition order of the catalyst components and a prescribed ageing phase. Copolymers obtained from various monomer feed ratios were characterized by ¹H and ¹³C NMR spectroscopy and gel-permeation chromatography (GPC). The copolymer characteristics especially microstructure, molar mass and molar-mass distribution (MMD) are strongly dependent on the composition of the monomer mixture.     

LED-compatible copper(II)-selective optrode membrane based on lipophilized Zincon

An optical single shot test for copper(II) ion is presented. The membrane consists of a polyester support and an active layer composed of hydrogel, a hydroxylic plasticizer, and Zincon. The latter has been made lipophilic by ion-pairing with tetraoctyl-ammonium bromide. The membrane responds to copper ions in giving a color change from pink to blue. Because the layer irreversibly extracts copper from the solution, a kinetic approach has been used for quantitation, in that the membrane has been exposed to the sample for 2 min and the initial slope of the response curve has been determined. A linear calibration graph has been obtained for the 1 to 100 mol/l (63.5 g/kg to 6.35 mg/kg) copper concentration range. The complexed form of the dye exhibits an absorption maximum of 620 nm which matches the emission band of the orange light-emitting diode (LED). Measurements have been performed at pH 6, because no complexation of zinc occurs in this range. The long term stability of the membrane exceeds 6 months when stored dry and in the dark. The strong binding of copper ions along with the fairly high selectivity of the membrane also suggests its use as a preconcentration phase.Dedicated to Professor Dr. Dieter Klockow on the occasion of his 60th birthday