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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 382 (1996), S. 525-528 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] An autocatalytic process in which the reaction product serves as the specific catalyst for its own synthesis by recognizing and promoting coupling of reactant(s) is the most basic form of molecular self-replication (Fig. 1). A few examples of non-enzymatic template-directed autocatalytic systems ...
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillan Magazines Ltd.
    Nature 389 (1997), S. 706-709 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The preparation of synthetic molecules showing the remarkable efficiencies characteristic of natural biopolymer catalysts remains a formidable challenge for chemical biology. Although significant advances have been made in the understanding of protein structure and function, the de novo ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillan Magazines Ltd.
    Nature 390 (1997), S. 591-594 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Symbiosis is an association between different organisms that leads to a reciprocal enhancement of their ability to survive. Similar mutually beneficial relationships can operate at the molecular level in the form of a hypercycle, a collective of two or more self-replicating species interlinked ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 1017-1024 
    ISSN: 0947-6539
    Keywords: autocatalysis ; coiled coil ; kinetics ; peptides ; self-replication ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A 32-residue α-helical peptide with a sequence similiar to that of the GCN4 leucine zipper region is shown to catalyze its own formation by accelerating the amide bond formation of a 17-residue peptide, preactivated as a thiobenzyl ester, and a 15-residue peptide with a N-terminal cysteine. The self-replication process displays parabolic growth characteristics as revealed by a detailed kinetic analysis. Control reactions with single-mutant peptides strongly support a mechanism in which a ternary and/or quaternary complex of the product with both peptide fragments act(s) as the catalytically active intermediate(s). Furthermore, these experiments reveal a remarkable sequence selectivity, as evidenced by the loss of autocatalytic activity as a result of a single replacement of leucine or valine residues with an alanine at the recognition interface.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 729-731 
    ISSN: 1434-1948
    Keywords: Catalysis ; Oligomerization ; Organometallics ; Oligopeptides ; Ruthenium complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Consecutive addition of one-equivalent portions of glycine ethyl ester to [(p-cymene)Ru(GGGOMe-H+)Cl] leads to considerable amounts of (tetra- to nonapeptide)ruthenium complexes in a one-pot reaction, in which the (p-cymene)RuCl fragment acts as a catalyst. The analogous reaction with alanine methyl ester affords AGGG and AAGGG complexes as the main products. The course of these metal-catalyzed peptide oligomerizations has been followed by mass spectrometry. The synthesis and characterization of the pentapeptide complex [(C6Me6)Ru(GGGGGOMe-H+)] is reported.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1187-1192 
    ISSN: 1434-1948
    Keywords: Iridium ; Rhodium ; Chloro-bridged complexes ; Heterobimetallic complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and characterization of heterobimetallic and mixed-valence complexes in which orthometalated [(ppy)2MCl] (M = Rh, Ir; ppy = 2-phenylpyridine anion) and [(bzq)2RhCl] (bzq = benzo[h]quinoline anion) fragments are linked via chloro-bridges with rhodium(I), iridium(I), palladium(II), and platinum(II) fragments is reported. These complexes are formed in nearly quantitative yields by metathesis reactions from the respective homodimeric compounds. The structures of [(ppy)2Rh(μ-Cl)2Rh(cod)] (cod = η4-1,5-cyclooctadiene) and [(ppy)2Rh(μ-Cl)2Pt(PBu3)-Cl] were determined by X-ray structure analyses.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1973 (1973), S. 380-386 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reaction of Quaternary Salts of 2-Chloro Heterocycles with Amines and PhenolN-Alkyl-2-chloro-substituted benzimidazolium-, 3H-indolium-, benzthiazolium- and quinolinium tetrafluoroborates 1 are attacked by the heteroatom of nucleophiles such as phenols, thiophenols, or N-alkylanilines. N,N-Dimethylaniline does not react with the benzimidazolium salt, but attacks the salts of the other three bases to yield 4 with a carbon-carbon bond between C-2 of the heterocycle and C-4 of the N,N-dimethylaniline. Rearrangements of the C—X to give a C—C bond in analogy to the chemistry of aromatic diazo compounds were not observed; however, exchange of an O- for an N-substituent proved to be possible. With pyrocatechol the spiro compound 5 could be prepared. Surprisingly the salts obtained yield good mass spectra with mostly high parent peaks. Valuable information about stabilities, particularly in the phenol series, can be deduced from the fragmentation products.
    Notes: N-Alkyl-2-chlor-substituierte Benzimidazolium-, 3H-Indolium-, Benzthiazolium- und Chinolinium-tetrafluoroborate 1 werden stets durch das Heteroatom X von Nucleophilen wie Phenolen, Thiophenolen oder N-Alkylanilinen angegriffen, wobei die Salze 3 entstehen. N,N-Dialkylanilin reagiert nicht mit dem Benzimidazoliumsalz, wird jedoch von den Salzen der drei anderen Basen unter Bildung von 4 mit einer C—C-Bindung zwischen C-2 des Heterocyclus und C-4 des N,N-Dimethylanilins angegriffen. Eine “Umkupplung” der C—X-Bindung von 3 zu einer C—C-Bindung nach Type 4 in Analogie zur Chemie aromatischer Diazoverbindungen wird nicht beobachtet. Jedoch gelingt der Austausch eines O- durch einen N-Substituenten. Mit Brenzkatechin wurde das Spiran 5 erhalten. Die dargestellten Salze liefern überraschenderweise gute Massenspektren mit größtenteils hohen Molekülpeaks. Die Zerfallsprodukte geben insbesondere in der Phenolreihe interessante Aufschlüsse über ihre Stabilität.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0009-2940
    Keywords: 1,7-Dimethylocta-2,6-diene-1,8-diyl ; Ruthenium complexes ; α-Amino carboxylates ; α-Amino acid esters ; Peptide esters ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Complexes Containing Biologically Important Ligands, LXXXLXXIX. Mitteilung: Lit. .  -  (η3:η3-C10H16)Ru(IV) Complexes with α-Amino Carboxylates, α-Amino Acid Esters, and Peptide Esters as LigandsReactions of the chloro-bridged bis(allyl) complex [(η3:η3-C10H16)Ru(Cl)(μ-Cl)]2 with α-amino carboxylates and α-amino acid esters afford the complexes (η3:η3-C10H16)(Cl)RuNH2CHRCO2 (2) and (η3:η3-C10H16)(Cl)2-RuNH2CHRCO2R′ (3). Abstraction of chloride from 3 by Ag+ gives the N,O-chelates [(η3:η3-C10H16)(Cl)RuNH2CHRCO2R′]+BF4 (4). Cysteine methyl ester forms the N,S-chelate complex (η3:η3-C10H16)(Cl)RuNH2CH(CO2CH3)CH2S (5), and with histidine methyl ester a dinuclear complex 6 with N,N-histidine bridge is obtained. Compound 3d with L-PheOEt as ligand was characterized by X-ray diffraction.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1127-1130 
    ISSN: 0009-2940
    Keywords: Rhodium(I) ; α-Aminocarboxylate ; Crystal structure ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Complexes Containing Biologically Important Ligands, LXXXPart LXXX: Ref. .  -  Synthesis and Crystal Structure of Rhodium(I) Chelates with α-Amino Carboxylates Part LXXX: Ref.The α-amino carboxylate complexes were prepared from Rh(Cl)(CO)(PPh3)2 and H2NC(H)(R)CO2 in the presence of AgBF4 and characterized by X-ray diffraction. In the crystal the complexes form chains by hydrogen bridges between amino and carboxylate groups of adjacent molecules.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0009-2940
    Keywords: Ruthenium complexes ; Osmium complex ; Hydrido complexes ; α-Amino acids ; Oxidative Addition ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal Complexes of Biologically Important Ligands, LXX[1].- Synthesis, Stereochemistry and Reactions of Ruthenium(II) and Osmium(II) Complexes with α-Amino CarboxylatesHerrn Professor Helmut Werner zum 60. Geburtstag gewidmet.The reactions of MHCl(CO)(PPh3)3 with salts of α-amino acids give the hydrido-N,O-chelate complexes MH(CO)(NH2CHR-COO)(PPh3)2 (1a-g;) M = Ru, Os). Complexes 1a-c can alternatively be prepared by oxidative addition of the appropriate α-amino acid to Ru(CO)3(PPh3)2. The crystal structure of 1b has been determined by an X-ray structural analysis. The leucinato compound 1c is an effective catalyst for the decomposition of formic acid. In contrast, reactions of RuHCl-(CO)(PPh3)3 with α-amino acids afford the chloro-N,O-che-late complexes RuCl(CO)(NH2CHRCOO)(PPh3)2 2a-h. The decomposition reactions of 2c, 2g and2h have been investigated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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