Browsing by Subject "Cyanamide"

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    Ground-glass hepatocytes. ligth and electron microscopy. Characterization of the different types
    (Murcia : F. Hernández, 1990) Jaime Vázquez, J.
    Morphological observations of paraffinembedded histological sections stained with H&E led to the discovery of some cytoplasmic changes which occur in different conditions, although they look alike under the light microscope. These hepatocytic changes consisted basically of homogeneous areas which are weakly eosinophilic in H & E-stained sections. They are frequently referred to as «inclusion» bodies, even when they are not true inclusions. The hepatocytic changes obsewed in HBsAg carriers, in chronic alcoholic patients treated with cyanamide to discourage them from drinking alcohol, in Lafora's disease, and in glycogenosis type IV, look very similar in paraffin sections stained with H&E. Nevertheless, they can be differentiated using ancillary techniques. On electron microscopy they do not look alike. Of particular interest are the «inclusion» bodies induced by cyanamide, a predictable and reproductible lesion, which in man eventually leads to cirrhosis. Other types of hepatocytic changes also giving a rather vague eground-glass» appearance to the cytoplasm are those resulting from intracytoplasmic accumulation of proteins, particularly fibrinogen, and those observed in patients treated with different drugs.
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    Intramolecular cyclization of Azido-Isocyanides triggered by the Azide Anion: an experimental and computational study
    (American Chemical Society Publications, 2023-06-20) Alajarín Cerón, Mateo; Cutillas Font, Guillermo; López Leonardo, Carmen; Orenes, Raul-Angel; Marín Luna, Marta; Pastor Vivero, Aurelia; Química Orgánica
    This work describes the unprecedented intramolecular cyclization occurring in a set of alfa-azido-beta-isocyanides in the presence of catalytic amounts of sodium azide. These species yield the tricyclic cyanamides [1,2,3]triazolo[1,5-a]quinoxaline-5(4H)-carbonitriles, whereas in the presence of an excess of the same reagent, the azido-isocyanides convert into the respective C-substituted tetrazoles through a [3+2] cycloaddition between the cyano group of the intermediate cyanamides and the azide anion. The formation of tricyclic cyanamides has been examined by experimental and computational means. The computational study discloses the intermediacy of a long-lived N-cyanoamide anion, detected by NMR monitoring of the experiments, subsequently converting into the final cyanamide in the rate determining step. The chemical behavior of these azido-isocyanides endowed with an aryl-triazolyl linker, has been compared with that of a structurally identical azido-cyanide isomer, experiencing a conventional intramolecular [3+2] cycloaddition between its azido and cyanide functionalities. The synthetic procedures described herein constitute metal-free approaches to novel complex heterocyclic systems, such as [1,2,3]triazolo[1,5-a]quinoxalines and 9H-benzo[f]tetrazolo[1,5-d][1,2,3]triazolo[1,5-a][1,4]diazepines.