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  • Chromium  (2)
  • Paxillus atrotomentosus  (2)
  • Toadstools  (2)
  • 2-Hexenoic acid, 4,5-epoxy-  (1)
  • 1
    ISSN: 0009-2940
    Keywords: α-Bromoglycine derivatives ; Amino acids ; Iron ; Chromium ; Tungsten ; Transition-metal-labeled α-amino acids ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of protected α-bromoglycine esters R1(O)CNHCH(Br)CO2R2 (R1=Ph, OCMe3; R2 =Me, tBu) with organometallic anions of acetylferrocene, CpFe(CO)(PPh3)-C(O)CH3, (OC)5M=C(OMe)CH3 (M=Cr, W), (OC)3Cr(η6-diphenylmethane), (OC)3Cr[η6-fluorene), (OC)3Cr(η6-dihydroanthracene) and of (OC)3Cr(-η6aniline) and (OC)3Cr(η6-o-toluidine) provide a method for the introduction of organometallic fragments into the side chains of α-amino acids.The complexes may be useful as markers for α-amino acids in peptides.The compound (OC))3Cr(η-o-C6H4(CH3)NHC-(H)(CO2Me)NHC(O)Ph was characterized by X-ray diffraction.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-1948
    Keywords: 2-Phenyl-4-R-5(4H)-oxazolones ; Iridium ; Palladium ; Platinum ; Iron ; Chromium ; C-o,N-Bridging 2-phenyloxazolone ; Peptide labelling ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of 2-phenyl-4-R-5(4H)-oxazolones (R = Me, CH2Ph, CHMeEt) with [(η5-C5Me5)IrCl2]2 afforded the cyclometallated complexes (η5-C5Me5)(Cl)Ir(L) (1-3) [L = 2-phenyl-4-R-5(4H)-oxazolone(C-o,N)]. 2-Phenyl-5(4H)-oxazolone reacts with [(η5-C5Me5)IrCl2]2 and palladium(II) acetate to give complexes with a C-o,N-bridging oxazolone [(η5-C5Me5)(Cl)Ir]2(μ-Cl)(μ-L-H+) (4) and Pd3(μ-ac)5(μ-L-H+) (5). 2-Phenyloxazolone anions were added to the π ligands of [(η5-C6H7)Fe(CO)3]+ and [(η7-C7H7)Cr(CO)3]+ to give the adducts 6-11. Dipeptide derivatives 12-18 were obtained by reaction of 1, 2 and by reaction of the adduct 6 from [(η5-C6H7)Fe(CO)3]+; and the anion of 2-phenyloxazolone with α-amino acid esters. These reactions may be used for the labelling of peptides. Saponification of 15-18 yields the organometallic substituted peptide acids 19-22. Their dianions (deprotonation of COOH and peptide amide) were used as ligands towards (Ph3P)2PtCl2 to yield the bimetallic complexes 23-25. The structures of 4, 5, 9 and 10 were determined by X-ray diffraction.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-193X
    Keywords: Triterpenoids ; Sodagnitins ; Chromogens ; Toadstools ; Natural Products ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -Fruit-bodies of the toadstools Cortinarius sodagnitus,C. fulvoincarnatus, C. arcuatorum(Agaricales) show a remarkable ink-red colour reaction when treated with aqueous base. We isolated six chromogens, named the sodagnitins A-F, from the toadstools and elucidated their structures by spectroscopic techniques. The sodagnitins are triterpenoids of the malabaricane type with a highly modified side chain. A mechanism for the colour reaction is proposed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0947-3440
    Keywords: Toadstools ; Tricholoma ; Trichaurantin ; Terpenoids ; Neodolastane, 2,3-seco- ; Dolastanes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel Diterpenoids from the Toadstools Tricholoma aurantium and T. fracticum (Agaricales)Herrn Professor Dr. Heinz G. Floss zum 60. Geburtstag gewidmet.Two novel diterpenoids trichaurantin (1) and its 6-O-acetyl derivative 2 have been isolated from Tricholoma species. Their structures were established by spectroscopic methods and an X-ray crystal analysis, 1 and 2 appear to be biosynthetically related to the neodolabellane and dolastane group of diterpenes and can be designated as 2,3-seconeodolastane derivatives.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0170-2041
    Keywords: Terphenyl derivatives ; Leucomentins ; 2-Hexenoic acid, 4,5-epoxy- ; Paxillus atrotomentosus ; Atromentin, precursor of ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fungal Pigments, 60. - Leucomentins, Colourless Precursors of Atromentin from the Mushroom Paxillus atrotomentosusAtromentin (1) occurs in sporophores of Paxillus atrotomentosus mainly in form of the colourless leucomentins 3-5. These compounds constitute esters of leucoatromentin with (2Z,4S,5S)-4,5-epoxy-2-hexenoic acid. The absolute configuration of the latter has been determined by its conversion into (+)-O-acetylosmundalactone (6a). The mechanism of the acid-catalyzed cleavage of the acyl residues has been studied by means of 18O labeling.
    Notes: Atromentin (1) liegt in Fruchtkörpern des Samtfußkremplings hauptsächlich in Form der farblosen Leucomentine 3-5 vor. Die Leucomentine sind Ester des Leukoatromentins mit (2Z,4S,5S)-4,5-Epoxy-2-hexensäure, deren absolute Konfiguration durch Überführung in (+)-O-Acetylosmundalacton (6a) bestimmt werden konnte. Dabei wurde der Mechanismus der säurekatalysierten Abspaltung der Säurereste durch 18O-Markierung aufgeklärt.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0170-2041
    Keywords: Fungal pigments ; Terphenylquinones ; Flavomentins ; Spiromentins ; Paxillus atrotomentosus ; Paxillus panuoides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Fungal Pigments, 61. - Flavomentins and Spiromentins, Novel Terphenylquinone Derivatives from Paxillus atrotomentosus and P. panuoides (Boletales)The gilled toadstools Paxillus atrotomentosus and P. panuoides produce small amounts of orange-yellow flavomentins and violet spiromentins. The flavomentins 1-3 constitute mono- and diesters of atromentin (6) with (2Z,4E)-2,4-hexadienoic acid or (2Z,4S,5S)-4,5-epoxy-2-hexenoic acid. In addition, 3-O-acetylatromentin (4) has been isolated from P. atrotomentosu. The spiromentins 8,11,12, and 13 possess a unique spiro structure in which a 4,5-dihydroxy-1,2-benzoquinone is linked to a lactone acetal unit. The structures of the pigments were confirmed by the synthesis of model compounds and the biomimetic conversion of flavomentin B (2) into the spiromentins B (11) and C (12).
    Notes: Die Kremplinge Paxillus atrotomentosus und P. panuoides produzieren in geringen Mengen orangegelbe Flavomentine und violette Spiromentine. Bei den Flavomentinen 1-3 handelt es sich um Ester des Atromentins (6) mit (2Z,4E)-2,4-Hexadiensäure oder (2Z,4S,5S)-4,5-Epoxy-2-hexensäure, außerdem kommt als weitere Verbindung dieses Typs 3-O-Acetylatromentin (4) vor. Die Spiromentine 8, 11, 12 und 13 besitzen eine ungewöhnliche Spirostruktur, in der ein 4,5-Dihydroxy-1,2-benzochinon mit einem Lacton acetalartig verknüpft ist. Die spektroskopisch abgeleiteten Strukturen der Farbstoffe konnten durch die Synthese von Modellverbindungen und die biomimetische Überführung von Flavomentin B (2) in die Spiromentine B (11) und C (12) gesichert werden.
    Additional Material: 1 Tab.
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