Chemie und Pharmazie - Open Access LMU - Teil 01/02

Dihydropyridine-sensitive voltage-dependent L-type calcium channels are critical to excitation-secretion and excitation-contraction coupling. The channel molecule is a complex of the main, pore-forming subunit alpha 1 and four additional subunits: alpha 2, delta, beta, and gamma (alpha 2 and delta are encoded by a single messenger RNA). The alpha 1 subunit messenger RNA alone directs expression of functional calcium channels in Xenopus oocytes, and coexpression of the alpha 2/delta and beta subunits enhances the amplitude of the current. The alpha 2, delta, and gamma subunits also have pronounced effects on its macroscopic characteristics, such as kinetics, voltage dependence of activation and inactivation, and enhancement by a dihydropyridine agonist. In some cases, specific modulatory functions can be assigned to individual subunits, whereas in other cases the different subunits appear to act in concert to modulate the properties of the channel.

The cloning of the cDNA for the α1 subunit of L-type calcium channels revealed that at least two genes (CaCh1 and CaCh2) exist which give rise to several splice variants. The expression of mRNA for these α1 subunits and the skeletal muscle α2/δ, β and γ subunits was studied in rabbit tissues and BC3H1 cells. Nucleic-acid-hybridization studies showed that the mRNA of all subunits are expressed in skeletal muscle, brain, heart and aorta. However, the α1-, β- and γ-specific transcripts had different sizes in these tissues. Smooth muscle and heart contain different splice variants of the CaCh2 gene. The α1, β and γ mRNA are expressed together in differentiated but not in proliferating BC3H1 cells. A probe specific for the skeletal muscle α2/δ subunit did not hybridize to poly(A)-rich RNA from BC3H1 cells. These results suggest that different splice variants of the genes for the α1, β and γ subunits exist in tissues containing L-type calcium channels, and that their expression is regulated in a coordinate manner.

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3692/ http://epub.ub.uni-muenchen.de/3692/1/3692.pdf Kaiser, Harald; Lindner, Jörg; Langhals, Heinz Kaiser, Harald; Lindner, Jörg und Langhals, Heinz (1991): Synthese von nichtsymmetrisch substituierten Perylen-Fluoreszenzfarbstoffen. In: Chemische Berichte, Vol. 124, Nr. 3: pp. 529-535. Chemie und Pharm

The lowest electronic transition of the fluorescent perylene dye bis-(3,5-di-tertbutylphenyl)-perylene-3, 4:9,10-biscarboximide has been investigated b

The solid state fluorescence of diketopyrrolopyrrole dyes and perylene-3,4:9,10- tetracarboxylic bisimides with alkyl substituents are investigated and compared with noncovalent interactions. The latter are estimated by crystal structure analysis, heats and entropies of fusion and solubilities in organic solvents. Applications of the dyes are discussed.

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3876/ http://epub.ub.uni-muenchen.de/3876/1/105.pdf Hagen, Gisela; Mayr, Herbert Hagen, Gisela und Mayr, Herbert (1991): Kinetics of the reactions of allylsilanes, allylgermanes, and allylstannanes with carbenium ions. In: Journal of the American Chemical Society, Vol. 113, Nr. 13: pp. 4954-4961.

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3877/ http://epub.ub.uni-muenchen.de/3877/1/107.pdf Bartl, Joerg; Steenken, Steen; Mayr, Herbert Bartl, Joerg; Steenken, Steen und Mayr, Herbert (1991): Kinetics of the reactions of laser-flash photolytically generated carbenium ions with alkyl and silyl enol ethers. Comparison with the reactivity toward alkenes, allylsilanes and alcohols. In: Journal of the Amer

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3905/ http://epub.ub.uni-muenchen.de/3905/1/3905.pdf Mayr, Herbert; Heilmann, Werner; Bäuml, Englbert; Vorbrüggen, Helmut Mayr, Herbert; Heilmann, Werner; Bäuml, Englbert und Vorbrüggen, Helmut (1991): Synthesis of 2,2,5,5-Tetramethylcyclopentanecarboxylic Acid. A Building Block of an Amino Acid Based Sweetener. In: Chemische Berichte, Vol. 124, Nr. 1: pp. 203-206.

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3906/ http://epub.ub.uni-muenchen.de/3906/1/3906.pdf Ohm, Stefan; Bäuml, Englbert; Mayr, Herbert Ohm, Stefan; Bäuml, Englbert und Mayr, Herbert (1991): A Versatile Synthesis of 1,4-Dienes. Use of Vinyl Ethers as Vinyl Cation Equivalents. In: Chemische Berichte, Vol. 124, Nr. 12: pp. 2785-2790. Chemie

Kinetics for the addition of the p-methoxybenzhydryl cation (AnPhCH+, 10) towards nonconjugated dienes 11 [H2C=C(CH3)-(CH2)n-C(CH3)=CH2] have been determined in CH2Cl2 at −30° to −70°C. Reactivity increases with increasing number of methylene groups separating the two double bonds. For N = 4, reactivity reaches the value for saturated alkyl substituents, and nucleophilic assistance of the second double bond is never observed.

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3939/ http://epub.ub.uni-muenchen.de/3939/1/3939.pdf Mayr, Herbert; Baran, Janusz; Heigl, Ulrich W. Mayr, Herbert; Baran, Janusz und Heigl, Ulrich W. (1991): 3,3,4,4,5,5-Hexamethyl-1,2-bis(methylene)cyclopentane. A Novel Probe for the Study of Cycloaddition Mechanisms. In: Gazzetta chimica italiana, Vol. 121, Nr. 8: pp. 373-381. Chemie und Pharmazie

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4009/ http://epub.ub.uni-muenchen.de/4009/1/015.pdf Vögtle, Fritz; Berscheid, Ralf; Schnick, Wolfgang Vögtle, Fritz; Berscheid, Ralf und Schnick, Wolfgang (1991): Inclusion of Acetonitrile in a Macrobicyclic Host Molecule. In: Journal of the Chemical Society, Chemical Communications: pp. 414-416. Chemie und Pharmazie

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4031/ http://epub.ub.uni-muenchen.de/4031/1/011.pdf Wagner, Ernst; Cotten, Matt; Foisner, Roland; Birnstiel, Max L. Wagner, Ernst; Cotten, Matt; Foisner, Roland und Birnstiel, Max L. (1991): Transferrin-polycation-DNA complexes. The effect of polycations on the structure of the complex and DNA delivery to cells. In: Proceedings of the National Academy of Science of the U S A, Vol. 88, Nr. 10: pp. 4255-4259.

Tue, 1 Jan 1991 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4032/ http://epub.ub.uni-muenchen.de/4032/1/012.pdf Curiel, David T.; Agarwal, Santosh; Wagner, Ernst; Cotten, Matt Curiel, David T.; Agarwal, Santosh; Wagner, Ernst und Cotten, Matt (1991): Adenovirus enhancement of transferrin-polylysine-mediated gene delivery. In: Proceedings of the National Academy of Science of the U S A, Vol. 88, Nr. 19: pp. 8850-8854. Chemie und Pharmazi

There are at least two different mechanisms for the transport of secretory proteins into the mammalian endoplasmic reticulum. Both mechanisms depend on the presence of a signal peptide on the respective precursor protein and involve a signal peptide receptor on the cis-side and signal peptidase on the trans-side of the membrane. Furthermore, both mechanisms involve a membrane component with a cytoplasmically exposed sulfhydryl. The decisive feature of the precursor protein with respect to which of the two mechanisms is used is the chain length of the polypeptide. The critical size seems to be around 70 amino acid residues (including the signal peptide). The one mechanism is used by precursor proteins larger than about 70 amino acid residues and involves two cytosolic ribonucleoparticles and their receptors on the microsomal surface. The other one is used by small precursor proteins and relies on the mature part within the precursor molecule and a cytosolic ATPase.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3618/ http://epub.ub.uni-muenchen.de/3618/1/003.pdf Rüffer, Martina; Zumstein, G.; Zenk, Meinhart H. Rüffer, Martina; Zumstein, G. und Zenk, Meinhart H. (1990): Partial purification and properties of S-Adenosylmethionine. (S)-tetrahydroprotoberberine-cis-N-methyltransferse from suspension cultured cells of Eschscholtzia and Corydalis. In: Phytochemistry, Vol. 29, Nr. 12: pp. 3727-3733. Chemie und Pharmazie

Complementary DNAs for the γ subunit of the calcium channel of rabbit skeletal muscle were isolated on the basis of peptide sequences derived from the purified protein. The deduced primary structure is without homology to other known protein sequences and is consistent with the γ subunit being an integral membrane protein.

The complete amino acid sequence of the receptor for organic calcium channel blockers (CaCB) from rabbit lung has been deduced by cloning and sequence analysis of the cDNA. Synthetic RNA derived from this cDNA induces the formation of a functional CaCB-sensitive high voltage activated calcium channel in Xenopus oocytes.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3689/ http://epub.ub.uni-muenchen.de/3689/1/3689.pdf Langhals, Heinz; Hadizamani, Katja Langhals, Heinz und Hadizamani, Katja (1990): Sextettumlagerungen als Solvens-Polaritätssonde. In: Chemische Berichte, Vol. 123, Nr. 2: pp. 407-409. Chemie und Pharmazie

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3690/ http://epub.ub.uni-muenchen.de/3690/1/3690.pdf Sachweh, Volker; Langhals, Heinz Sachweh, Volker und Langhals, Heinz (1990): Synthese von Reinst-Rubicen und Rubicen-Derivaten. In: Chemische Berichte, Vol. 123, Nr. 10: pp. 1981-1987. Chemie und Pharmazie

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3691/ http://epub.ub.uni-muenchen.de/3691/1/3691.pdf Naumann, Christoph; Langhals, Heinz Naumann, Christoph und Langhals, Heinz (1990): Synthese von 1,7-Diazaperylen. In: Chemische Berichte, Vol. 123, Nr. 9: pp. 1881-1884. Chemie und Pharmazie

A mixture of solid KOH in dimethyl sulfoxide has a strong basicity, but only a low nucleophilicity and is used for methylation of ketones. With this simple and inexpensive reagent complete methylation with yields up to 90% can be achieved.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3731/ http://epub.ub.uni-muenchen.de/3731/1/063.pdf Naumann, Christoph; Langhals, Heinz Naumann, Christoph und Langhals, Heinz (1990): A Simple Synthesis of Dihydroxybipyridyls. In: Synthesis, Vol. 123: pp. 407-409. Chemie und Pharmazie

The two coupling agents SPDP (N-succinimidyl-3-(2-pyridyldithio)propionate) and SATA (N-succinimidyl-S-acetylthioacetate) were compared in their efficiency and feasibility to couple monoclonal antibodies (Abs) via thioether linkage to liposomes functionalized by various lipophilic maleimide compounds like Full-size image methyl ester (MP-PL), N-(3-maleimidopropionyl)phosphatidylethanolamide (MP-PE), Full-size image methyl ester (EMC-PL), and N-(6-maleimidocaproyl)phosphatidylethanolamine (EMC-PE). The composition of the liposomes was soy phosphatidylcholine (SPC), cholesterol, maleimide compounds and -tocopherol (1:0.2:0.02:0.01, mol parts), plus N4-oleylcytosine arabinoside (NOAC) as cytostatic prodrug (0.2 mol parts) and a new, lipophilic and highly fluorescent dye N,N′-bis(1-hexylheptyl)-3,4:9,10-perylenebis(dicarboximide) (BHPD, 0.006 mol parts). From the maleimide derivatives MP-PL was the most effective in terms of preservation of the coupling activity in dependence of liposome storage. The coupling of the monoclonal A B8-24.3 (mouse IgG2b, MHC class I, anti H-2kb) and IB16-6 (rat IgG2a, anti B16 mouse melanoma) to the drug carrying liposomes was more effective and easier to accomplish with SATA as compared to SPDP. Coupling rates of 60–65% were obtained with SATA at molar ratios of 12 SATA:1 Ab:40 maleimide spacer groups on the surface of one liposome. The highest coupling rates with SPDP were obtained at the ratio of 24 SPDP:1 Ab:40 liposomal maleimide groups, with an Ab binding efficiency of only 20–25%. The optimal in vitro binding conditions to specific target cells (EL4 for B8-24.3-liposomes and B16-F10 for IB16-6-liposomes) were determined by cytofluorometric measurement of the liposomal BHPD fluorescence with SATA linked Abs. Optimal immunoliposome binding to specific epitopes on the target cells was achieved with 1–2 Ab molecules coupled to one liposome, with immunoliposome concentrations of 20–130 nM and with a small incubation volume of 0.3–0.4 ml. The specificity of the binding of B8-24.3-liposomes to EL4 target cells was visualized by scanning electron microscopy. Antibody mediated endocytic uptake of immunoliposomes could be demonstrated by transmission electron microscopy.

A procedure for the UV/VIS-spectroscopic determination of water by the use of a solvatochromic pyridiniumphenolate betaine is given. The water content of organic solvents is calculated by a two parameter equation from λmax of the dye. A typical, detection limit is of the order of 1 mg in 1 ml solvent for routine spectrometers. The parameters for the determination of water are given for a number of commonly used solvents.

The 2-chloro-3-(2′-chloroalkyl)cyclopropenones 4, readily obtained by hydrolysis of the adducts of the trichlorocyclopropenylium ion onto alkenes, thermally rearrange to propiolic acid chlorides 6. Treatment of 4 with TosOH·H2O in CH2Cl2 yields the (E)-3-chloro-2-(2′-chloroalkyl)acrylic acids 9, which have been converted in two simple steps to -methylene-γ-butyrolactones 11 with good overall yields.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3873/ http://epub.ub.uni-muenchen.de/3873/1/095.pdf Mayr, Herbert; Schneider, Reinhard; Schade, Christian; Bartl, Joerg; Bederke, Rainer Mayr, Herbert; Schneider, Reinhard; Schade, Christian; Bartl, Joerg und Bederke, Rainer (1990): Addition reactions of diarylcarbenium ions to 2-methyl-1-pentene. kinetic method and reaction mechanism. In: Journal of the American Chemical Society, Vol. 112, Nr. 11: pp. 4446-4454.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3874/ http://epub.ub.uni-muenchen.de/3874/1/096.pdf Mayr, Herbert; Schneider, Reinhard; Irrgang, Bernhard; Schade, Christian Mayr, Herbert; Schneider, Reinhard; Irrgang, Bernhard und Schade, Christian (1990): Kinetics of the reactions of the p-methoxy-substituted benzhydryl cation with various alkenes and 1,3-dienes. In: Journal of the American Chemical Society, Vol. 112, Nr. 11: pp. 4454-4459.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3875/ http://epub.ub.uni-muenchen.de/3875/1/101.pdf Bartl, Joerg; Steenken, S.; Mayr, Herbert; McClelland, R. A. Bartl, Joerg; Steenken, S.; Mayr, Herbert und McClelland, R. A. (1990): Photo-heterolysis and -homolysis of substituted diphenylmethyl halides, acetates, and phenyl ethers in acetonitrile: characterization of diphenylmethyl cations and radicals generated by 248-nm laser flash photoly

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3904/ http://epub.ub.uni-muenchen.de/3904/1/3904.pdf Mayr, Herbert; Cambanis, Anton; Bäuml, Englbert Mayr, Herbert; Cambanis, Anton und Bäuml, Englbert (1990): Notizen/Notes Synthesis of -Oxo Esters from Silyl Enol Ethers and Dichlorobis(phenoxy)methane. In: Chemische Berichte, Vol. 123, Nr. 7: pp. 1571-1573.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3938/ http://epub.ub.uni-muenchen.de/3938/1/097.pdf Mayr, Herbert; Schneider, Reinhard; Grabis, Ute Mayr, Herbert; Schneider, Reinhard und Grabis, Ute (1990): Linear free energy and reactivity-selectivity relationships in reactions of diarylcarbenium ions with .pi.-nucleophiles. In: Journal of the American Chemical Society, Vol. 112, Nr. 11: pp. 4460-4467.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4010/ http://epub.ub.uni-muenchen.de/4010/1/017.pdf Schnick, Wolfgang; Lücke, Jan Schnick, Wolfgang und Lücke, Jan (1990): Lithium ion conductivity of LiPN2 and Li7PN4. In: Solid State Ionics, Vol. 38, Nr. 3-4: pp. 271-273. Chemie und Pharmazie

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4013/ http://epub.ub.uni-muenchen.de/4013/1/019.pdf Schnick, Wolfgang; Lücke, Jan Schnick, Wolfgang und Lücke, Jan (1990): Synthesis and crystal structure of lithium phosphorus nitride Li7PN4. The first compound containing isolated PN4-tetrahedra. In: Journal of Solid State Chemistry, Vol. 87, Nr. 1: pp. 101-106.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4026/ http://epub.ub.uni-muenchen.de/4026/1/005.pdf Wagner, Ernst; Xiang, Yi-Bin; Baumann, Karl; Gück, Jürgen; Eschenmoser, Albert Wagner, Ernst; Xiang, Yi-Bin; Baumann, Karl; Gück, Jürgen und Eschenmoser, Albert (1990): Chemie von alpha-Aminonitrilen. Aziridin-2-carbonitril, ein Vorläufer von rca-O3-Phosphoserinnitril und Glycolaldehyd-phosphat. In: Helvetica Chimica Acta, Vol. 73, Nr. 5: pp. 1391-1409.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4027/ http://epub.ub.uni-muenchen.de/4027/1/006.pdf Müller, Daniel; Pitsch, Stefan; Kittaka, Atsushi; Wagner, Ernst; Wintner, Claude E.; Eschenmoser, Albert Müller, Daniel; Pitsch, Stefan; Kittaka, Atsushi; Wagner, Ernst; Wintner, Claude E. und Eschenmoser, Albert (1990): Chemie von a-Aminonitrilen. Aldomerisierung von Glycolaldehyd-phosphat zu racemischen Hexose-2,4,6-triphosphaten und (in Gegenwart von Formaldehyd) racemischen Pentose-2,4-diphosphaten: rac-Al

We have developed a high-efficiency nucleic acid delivery system that uses receptor-mediated endocytosis to carry DNA macromolecules into cells. We accomplished this by conjugating the iron-transport protein transferrin to polycations that bind nucleic acids. Human transferrin, as well as the chicken homologue conalbumin, has been covalently linked to the small DNA-binding protein protamine or to polylysines of various sizes through a disulfide linkage. These modified transferrin molecules maintain their ability to bind their cognate receptor and to mediate efficient iron transport into the cell. The transferrin-polycation molecules form electrophoretically stable complexes with double-stranded DNA, single-stranded DNA, and modified RNA molecules independent of nucleic acid size (from short oligonucleotides to DNA of 21 kilobase pairs). When complexes of transferrin-polycation and a bacterial plasmid DNA containing the gene for Photinus pyralis luciferase are supplied to eukaryotic cells, high-level expression of the luciferase gene occurs, demonstrating transferrin receptor-mediated endocytosis and expression of the imported DNA. We refer to this delivery system as "transferrinfection."

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4029/ http://epub.ub.uni-muenchen.de/4029/1/008.pdf Zenke, Martin; Steinlein, Peter; Wagner, Ernst; Cotten, Matt; Beug, Hartmut; Birnstiel, Max L. Zenke, Martin; Steinlein, Peter; Wagner, Ernst; Cotten, Matt; Beug, Hartmut und Birnstiel, Max L. (1990): Receptor-mediated endocytosis of transferrin-polycation conjugates. An efficient way to introduce DNA into hematopoietic cells. In: Proceedings of the National Academy of Science of the U S A, Vol. 87, Nr. 10: pp. 3655-3659.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4030/ http://epub.ub.uni-muenchen.de/4030/1/009.pdf Cotten, Matt; Längle-Rouault, Francoise; Kirlappos, Helen; Wagner, Ernst; Mechtler, Karl; Zenke, Martin; Beug, Hartmut; Birnstiel, Max L. Cotten, Matt; Längle-Rouault, Francoise; Kirlappos, Helen; Wagner, Ernst; Mechtler, Karl; Zenke, Martin; Beug, Hartmut und Birnstiel, Max L. (1990): Transferrin-polycation-mediated introduction of DNA into human leukemic cells. Stimulation by agents that affect the survival of transfected DNA or modulate transferrin receptor levels. In: Proceedings of the National Academy of S

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4163/ http://epub.ub.uni-muenchen.de/4163/1/043.pdf Moller, Karin; Bein, Thomas Moller, Karin und Bein, Thomas (1990): Reduction and cluster growth of palladium in zeolite Y containing transition metal ions. X-ray absorption studies. In: Journal of Physical Chemistry, Vol. 94, Nr. 2: pp. 845-853.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4180/ http://epub.ub.uni-muenchen.de/4180/1/037.pdf Ozkar, Saim; Ozin, Geoffrey A.; Moller, Karin; Bein, Thomas Ozkar, Saim; Ozin, Geoffrey A.; Moller, Karin und Bein, Thomas (1990): Intrazeolite metal carbonyl topotaxy. A comprehensive structural and spectroscopic study of intrazeolite Group VI metal hexacarbonyls and subcarbonyls. In: Journal of the American Chemical Society, Vol. 112, Nr.

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4186/ http://epub.ub.uni-muenchen.de/4186/1/041.pdf Borvornwattananont, Aticha; Moller, Karin; Bein, Thomas Borvornwattananont, Aticha; Moller, Karin und Bein, Thomas (1990): Intrazeolite attachment of a Ge–Mo heterobimetallic complex. In: Journal of the Chemical Society, Chemical Communications, Vol. 28: pp. 28-29. Chemie und Pharmazie

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4191/ http://epub.ub.uni-muenchen.de/4191/1/4191.pdf Enzel, Patricia; Bein, Thomas Enzel, Patricia und Bein, Thomas (1990): Encapsulation of conducting polymers within zeolites. In: NATO ASI Series, B: Physics, Vol. 248: pp. 421-426. Chemie und Pharmazie

Mon, 1 Jan 1990 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4194/ http://epub.ub.uni-muenchen.de/4194/1/4194.pdf Bein, Thomas; Enzel, Patricia; Beuneu, F.; Zuppiroli, L. Bein, Thomas; Enzel, Patricia; Beuneu, F. und Zuppiroli, L. (1990): Stabilization of conducting heteroaromatic polymers in large-pore zeolite channels. In: Advances in Chemistry Series: pp. 433-449. Chemie un

The relative contributions of external and intracrystalline acidic sites of small pore H-RHO zeolite for the selective synthesis of methylamines from methanol and ammonia have been studied. Nonselective surface reactions which produce predominantly trimethylamine can be eliminated by “capping” the external acidic sites with trimethylphosphite (TMP) and other reagents, thus improving the selectivity toward the formation of dimethylamine. For small pore zeolites, neither the zeolite pore size nor the internal acidic sites is significantly affected by this treatment. In situ infrared and MAS-NMR studies show that TMP reacts irreversibly with the zeolite acidic sites via a modified Arbusov rearrangement to form surface-bound dimethylmethylphosphonate.

Aniline has been polymerized in the three-dimensional channel system of zeolite Y. The monomer was diffused into zeolites with different levels of acidity from hexane solution. Subsequent admission of peroxydisulfate or iodate from aqueous solution yielded the intrazeolite polymers, as demonstrated by FT-IR, electronic absorption data and recovery of the included polymer. With S2O82-, the intrazeolite products are a function of the proton content of the zeolite. Polymer is only formed when a sufficient supply of protons is present in the zeolite host. When neutral iodate solution is used, no polymer is formed in NaY and acid zeolites, but at low pH aniline polymerizes in all zeolites. The open pore system of the zeolite host can be accessed by base such that the intrazeolite protonated polymer is transformed into the corresponding neutral polymer. The polymer chains encapsulated in zeolite hosts represent a new class of low- dimensional electronic materials.

Semiconducting materials such as CdSe, CdS, PbS and GaP are included in crystalline zeolite Y and mordenite and structurally flexible ethylene-methacrylic acid copolymer solid matrices. EXAFS analysis reveals formation of species with dimensions of molecular size up to ca. 13 A in the crystalline hosts, while the polymer matrices allow agglomeration of larger semiconducting particles. Zeolite anchored structures are distinctively different to small particles with bulk crystal structure as usually found in colloidal systems.

Coordination Chemistry of rr-Bonded Cyclopentadienyl Chalcogeno Ethers, I. - Chelate Complexes of Pentakis(methylthio)cymantrene with Metal Carbonyls [C5(SMe)5]Mn(CO)3 (1) reacts with W(CO)5(THF), Mo(CO)4(C7H8), Cr(CO)3(NCMe)3, and Re(CO)4(-C3H5)/HBF4 to yield the monochelate complexes [[C5(SMe)5]Mn(C0)3][M(CO)4] (M = W: 2; M = Mo: 3) and the dichelate complexes [[C5(SMe)5]Mn(CO)3][M(C0)4]2 (M = W: 4; M = Cr: 5; M = Re BFF4 : 6). The reaction with Mo(CO)3(p-xylene) in THF leads via unstable intermediates, which contain coordinated THF, to a mixture of 3 and [[C5(SMe)5]Mn(CO)3][Mo(CO)4]2 (7). The structures of 3 and 4 in the crystal have been determined by X-ray diffraction methods.

Die Reaktion von (η5-C5H5)Co(CO)2 mit ClCCCl ergibt neben Hexachlorbenzol mindestens sechs verschiedene Produkte, von denen drei durch Röntgenstrukturanalyse charakterisiert werden konnten: Der erste π-Komplex von Hexachlortropon, (CpCo)(η4-C7Cl6O) weist η4-Koordination zweier nicht benachbarter Doppelbindungen auf, was bisher in anderen Komplexen mit Cycloheptatrienon-Liganden nicht beobachtet wurde. Ebenfalls zum erstenmal wird die Struktur eines 1,2-Dikobaltacycloheptadienons beschrieben. Schließlich konnte die Struktur eines bimetallischen Tetrahchlorocobaltacyclopentadienons kristallographisch bestätigt werden.

Fri, 1 Dec 1989 12:00:00 +0100 http://epub.ub.uni-muenchen.de/8581/ http://epub.ub.uni-muenchen.de/8581/1/Mueller_Guenter_8581.pdf Müller, Günter; Bandlow, Wolfhard Müller, Günter und Bandlow, Wolfhard (Dezember 1989): An amphitropic cAMP-binding protein in yeast mitochondria. 1. Synergistic control of the intramitochondrial location by calcium and phospholipid. In: Biochemistry, Vol. 28, Nr. 26: pp. 9957-9967. Chemie und Pharmazie

Fri, 1 Dec 1989 12:00:00 +0100 http://epub.ub.uni-muenchen.de/8588/ http://epub.ub.uni-muenchen.de/8588/1/Mueller_Guenter_8588.pdf Müller, Günter; Bandlow, Wolfhard Müller, Günter und Bandlow, Wolfhard (Dezember 1989): An amphitropic cAMP-binding protein in yeast mitochondria. 3. Membrane release requires both calcium-dependent phosphorylation of the cAMP-binding protein and a phospholipid-activated mitochondrial phospholipase. In: Biochemistry, Vol. 28, Nr. 26: pp. 9974-9981. Chemie und Pharmazie

Honeybee prepromelittin (70 amino acid residues), the precursor of an eukaryotic secretory protein, and a hybrid protein between prepromelittin and mouse dihydrofolate reductase (257 amino acid residues) were expressed in Escherichia coli and characterized with respect to their requirements for transport across the plasma membrane. Both precursor proteins are posttranslationally processed and exported into the periplasm, and they both depend on the membrane potential for this to occur. With respect to dependence on components of the export machinery, however, the two precursor proteins show striking differences: the small precursor protein prepromelittin does not require the function of proteins secA and secY; the large precursor protein prepromelittin-dihydrofolate reductase, on the other hand, depends on both components. The implications of these observations with respect to the mechanisms of protein export in E. coli and of protein import into the endoplasmic reticulum are discussed.