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  • Angiosperms  (2)
  • 2-Acetoxy-3-amino-dienes-(2,4)  (1)
  • 1990-1994
  • 1985-1989  (3)
  • 1988  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Cathodic synthesis of 2-amino-2-propene-1-ones electrolytical studies on vinylazides, VII (1988)
    Springer
    Monatshefte für Chemie 119 (1988), S. 223-232 
    Details
    ISSN: 1434-4475
    Keywords: Enazidoketones ; Enaminoketones ; 2-Acetoxy-3-amino-dienes-(2,4) ; Cathodic reduction mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Die kathodische Synthese von Enaminoketonen aus ungesättigten Azidoketonen wurde auf heteroaromatisch substituierte und auf rein aliphatische Derivate übertragen. Zum Reduktionsmechanismus wurde der Einfluß verschiedener Stellen der Protonierung (am N1 der N3-Gruppe bzw. an der Carbonylgruppe), abhängig von Potential und Säurestärke, untersucht. Aldehydische Gruppen als weitere funktionelle Gruppen im Enazid werden leichter als die Vinylazide reduziert. Die rein aliphatischen Enazidoketone ergeben bei reduktiver Acylierung konjugierte Diene.
    Notes: Abstract The cathodic preparation of enamino ketones from enazidoketones has been generalised to include heteroaromatic and aliphatic derivatives. Mechanistically the role of different sites of protonation, either on N1 of the N3-group or on carbonyl depending on electrolysis potential and acid strength, apparent by product distribution, is clarified. Aldehydic groups are preferentially reduced compared to the vinylazide part. Purely aliphatic azidoketones yield conjugated dienes under reductive acetylation, which might be useful for cycloaddition reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00809596
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  • 2
    Electronic Resource
    Electronic Resource
    Typology of latex starch grains of certainEuphorbiaceae and their possible significance in systematics (1988)
    Springer
    Plant systematics and evolution 160 (1988), S. 189-193 
    Details
    ISSN: 1615-6110
    Keywords: Angiosperms ; Euphorbiaceae ; Euphorbia ; Chamaesyce ; Latex starch grains ; phylogenetic and taxonomic implications
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Latex starch grains of certain Indian species ofEuphorbiaceae belonging toEuphorbia, Chamaesyce, Pedilanthus, Synadenium andMonadenium have been studied. They exhibit distinct shapes in different taxa, i.e., rod, spindle, osteoid, dumb-bell and discoid. This helps i.a. in the taxonomic circumscription ofChamaesyce fromEuphorbia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00936046
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  • 3
    Electronic Resource
    Electronic Resource
    Studies in the embryology of the diandrous orchidCypripedium cordigerum (Cypripedieae, Orchidaceae) (1988)
    Springer
    Plant systematics and evolution 160 (1988), S. 159-168 
    Details
    ISSN: 1615-6110
    Keywords: Angiosperms ; Orchidaceae ; Cypripedieae ; Cypripedium cordigerum ; Embryology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The anther wall layers ofCypripedium cordigerum are six to eight. The glandular tapetum is 2- or 3-layered and its cells are uninucleate. Simultaneous cytokinesis results in decussate, isobilateral and tetrahedral pollen tetrads. Ripe pollen grains are 2-celled. The mature ovules are anatropous, bitegmic and tenuinucellate. Both the integuments are dermal in origin and 2-layered. The inner integument alone forms the micropyle. The female gametophyte is 6-nucleate and bisporic. The reduction of nuclei is due to the “strike” phenomenon. Double fertilization occurs. The primary endosperm nucleus divides to form two free endosperm nuclei. The mature embryo is undifferentiated. The cells ca, m and n contribute to the embryo. The suspensor is single-celled. The seed coat is formed entirely by the outer layer of the outer integument. There are three sterile and three fertile valves in the ovary. In the prefertilization stages these valves consist of parenchymatous cells with starch and raphides. After fertilization, the sterile valves develop sclerotic cells whereas the fertile valves remain parenchymatous. The pericarp structure and embryological features support the retention of tribeCypripedieae within theOrchidaceae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00936043
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