English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/36221
Title: Synthesis, structure (NMR and mass spectrometry) and conformational analysis of heterocyclic analogues of dibenzo[a,e]cycloocta-1,5-diene: 5,6,12,13-tetrahydrobispyrazolo [1,2-a:1',2'-e][1,2,5,6] tetraazocinediium dihalides
Authors: Cabildo, Pilar; Claramunt, Rosa M.; Cornago, Pilar; Lavandera, José Luís; Sanz, Dionísia; Jagerovic, Nadine; Jimeno, M. Luisa; Elguero, José; Gilles, Isabelle; Aubagnac, Jean-Louis
Issue Date: 1996
Publisher: Royal Society of Chemistry (Great Britain)
Citation: Journal Cover:J. Chem. Soc., Perkin Trans. 2, 1996, 701-711 Journal of the Chemical Society, Perkin Transactions 2 (4) : 701-711 (1996)
Abstract: Several 5,6,12,13-tetrahydrobispyrazolo[1,2-a:1′,2′-e][1,2,5,6] tetraazocinediium dihalides 4a–d and 8 are prepared from pyrazole, 3,5-dimethylpyrazole, 4-(1-adamantyl)pyrazole and campho[2,3-c]pyrazole by stepwise alkylation with 1,2-dibromoethane or 1,2-dichloroethane. Their structural characterization has been achieved by NMR and mass spectrometry. Dynamic NMR spectroscopy allowed the measurement of the barrier for the chair–chair interconversion in the case of the parent compound 4a and the 1,3,8,10-tetramethyl derivative 4b. These barriers as well as the preferred chair conformation are rationalized through semi-empirical and molecular mechanics calculations with regard to dibenzo[a,e]cycloocta-1,5-diene. The study of doubly charged bispyrazolium salts allows demonstration of their reduction by addition of a hydride ion [C+++ H–→(C + H)+] during FABMS experiments.
Publisher version (URL): http://dx.doi.org/10.1039/P29960000701
URI: http://hdl.handle.net/10261/36221
DOI: 10.1039/P29960000701
ISSN: 0300-9580
Appears in Collections:(CENQUIOR) Artículos
Files in This Item:
There are no files associated with this item.
Show full item record

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.