Výsledky vyhledávání - "Marina Rentzea"

Cyclization of diaza[6]helicenes to monoazacoronenes under electron impact

Autor: Michael Diehm, Marina Rentzea, Heinz A. Staab

Publikováno v: Tetrahedron Letters

Electron impact (EI)-induced cyclizations of 1,16-diaza[6]helicene (1), of 1,14-diaza[6]helicene (2) and of 3,14-diaza[6]helicene (3) to monoazacoronenes (abundant loss of HCN and H) were investigated through their source spectra supported by accurat

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::14b08f2bb8155136b574e528fa2e0f53
https://hdl.handle.net/11858/00-001M-0000-0019-A8AB-C11858/00-001M-0000-002D-AFAA-6

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Reactions within and between adjacent dimethylamino groups: Collision-induced dissociation tandem mass spectrometric study of the 1,9-bis(dimethylamino)phenalenium cation

Autor: Marina Rentzea, Jörg Hofmeister, Heinz A. Staab

Publikováno v: Organic Mass Spectrometry

The electron impact (EI) ionization-induced fragmentation pathways of the new 1,9-bis(dimethylamino) phenalenium cation [1]+ were investigated. The peri-dimethylamino substituents of [1]+ are incorporated in a trimethine cyanine substructure and show

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::13e26e0c63d2867d21013d5b66db028c
https://hdl.handle.net/11858/00-001M-0000-0019-AA74-911858/00-001M-0000-0019-AA76-5

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Behaviour of salts of very strong proton-sponge bases in the gas phase: Extended proximity effects and maintenance of the hydrogen bridge under soft ionization. An electron impact and liquid secondary ion mass spectrometric/collision-induced dissociation tandem mass spectrometric study

Autor: Marina Rentzea, Heinz A. Staab, Fredy Kühn

Publikováno v: Organic Mass Spectrometry

The liquid secondary ion mass spectrometry and electron impact ionization fragmentation pathways of 1,9-bis(dimethylamino)-2,8-dimethoxy-dibenzofuran (1), a new proton-sponge base with increased steric compression (buttressing) and much higher basici

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::69c23394194a052f863c6d76893e0521
https://hdl.handle.net/11858/00-001M-0000-0019-AA6B-011858/00-001M-0000-0019-AA6D-C

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7H-benz [kl]acridin-7-ylium closed-shell ion produced from 1,8-bis(phenylamino)naphthalenes under electron impact: Tandem mass spectrometric structure elucidation

Autor: Marina Rentzea, Franz A. Neugebauer, Gösta Rimmler

Publikováno v: Organic Mass Spectrometry

Not only strongly basic aromatic amines such as ‘proton sponges’ show characteristic [M – Me2NH – H]+ peaks corresponding to cyclization to stable heterocyclic ions under electron impact. The fragmentation of the title compounds, which are we

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fc0025bd4407077caccc068e7f55e625
https://hdl.handle.net/11858/00-001M-0000-0019-AA67-711858/00-001M-0000-0019-AA65-B

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Proximity effects in the mass spectra of crowded bis(dialkylamino)arenes. Part IV: A tandem mass spectrometry study of fluorenodiazonine and fluorenodiazecine derivatives

Autor: Marina Rentzea, Wolfgang Brox, Heinz A. Staab

Publikováno v: Organic Mass Spectrometry

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4eba1835518f45d8337ba7ea30c8db29
https://hdl.handle.net/21.11116/0000-0002-55D8-B11858/00-001M-0000-0019-AC1D-0

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Proximity effects in the mass spectra of bis(dimethylamino)arenes, III, intramolecular cyclization of 2,2′-bis(dimethylamino)biphenylsunder electron impact

Autor: Matthias Höne, Heinz A. Staab, Marina Rentzea

Publikováno v: Tetrahedron Letters

There are not only strongly crowded “proton sponges” that show characteristic [M-Me 2 NH-H] + peaks corresponding to cyclization to stable, even electron heterocyclic ions under EI. Fragmentation of title compounds which are moderately strong, no

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::81fddea6d56baac450b673c1f2d952a1
https://doi.org/10.1016/s0040-4039(00)80831-x

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Electron donor‐acceptor compounds, XXXVI. Quinones and quinhydrones of the [2.2]‐ and [3.3]metaparacyclophane series

Autor: Claus Krieger, Marina Rentzea, Manfred Jörns, Heinz A. Staab

Publikováno v: Chemische Berichte

The isomeric quinhydrones 1 and 2 as well as the bis(quinone) 6 of the [2.2]metaparacyclophane series were synthesized. Precursor of these products was the tetramethoxy[2.2]metaparacyclophane 3 which was prepared via 4 and 5. X-ray structure analyses

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f8bf01162d867f308074e20c0010b1e8
https://doi.org/10.1002/cber.19851180238

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Bis(tricarbonyliron) complexes of -quinodimethanes: fragmentation and isomerisation under electron impact

Autor: Marina Rentzea, Heinz A. Staab, Ali R. Koray

Publikováno v: Tetrahedron Letters

EI mass spectra of trans -η 4 ,η 4 -[3,6-bis(methylene)-1,4-cyclohexadiene]-bis=(tricarbonyliron) complexes 1a , b are reported. The fragmentation pathway is rationalized by assuming a rearrangement of the trans -bis(tricarbonyliron) complexes into

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::090565f643405af0ed530fbc642110c8
https://doi.org/10.1016/s0040-4039(00)98837-3

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α-ketol-umlagerung von myrsinol zum iso-myrsinol und mögliche biogenese des myrsinan-derüstes

Autor: E. Hecker, Marina Rentzea

Publikováno v: Tetrahedron Letters. 23:1785-1788

Myrsinol-3,5,7-triesters undergo a base catalyzed acyloin rearrangement to yield quantitatively derivatives of 1,2,3,4,4a,5,8,8a,9,9a,10,10a-dodecahydroanthracene. The structures and reactions of myrsinol, its rearrangement product iso-myrsinol and d

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::adcc630f145b74ba34a29c0aa8010259
https://doi.org/10.1016/s0040-4039(00)86741-6

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Neue Tetrazyklische, polyfunktionelle diterpenoide aus euphorbia myrsinites L. röntgenstrukturanalyse und stereochimie des 14-desoxo-14β-hydroxymyrsinols

Autor: Hermann Lotter, Marina Rentzea, E. Hecker

Publikováno v: Tetrahedron Letters. 23:1781-1784

Two groups of new polyfunctional diterpenes were isolated from E. myrsinites L.: the hitherto unknown irritant and cocarcinogenic esters M2 and M′2 of the tetracyclic, polyfunctional diterpene ingenol and six non-irritant mixtures of esters M1, M3

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::bd20140e6bb32f1a82d1a1d770dbe99c
https://doi.org/10.1016/s0040-4039(00)86740-4

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