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Ring-Transformationen bei der Umsetzung von 3-(Dimethylamino)-2,2-dimethyl-2H-azirin mit 1-substituierten Imidazolidin-2,4,5-trionen


Schläpfer-Dähler, Marlise; Heimgartner, Heinz (1993). Ring-Transformationen bei der Umsetzung von 3-(Dimethylamino)-2,2-dimethyl-2H-azirin mit 1-substituierten Imidazolidin-2,4,5-trionen. Helvetica Chimica Acta, 76:2321-2328.

Abstract

Ring-Transformations in the Reaction of 3-(Dimethylamino)-2,2-dimethyl-2H-azirines with 1-Substituted Imidazolidine-2,4,5-triones. Reaction of 1-substituted imidazolidine-2,4,5-triones (= N-substituted parabanic acids; 2) and 3-(dimethylamino)-2,2-dimethyl-2H-azirine (1) in iPrOH or MeCN at room temperature yields 5,6,7,7a-tetrahydro-3H-imidazo[3,4-a]imidazole-5,7-diones 3 (Scheme 1). By 15N-NMR studies, using (3-15N)-2a, it has been shown that only N(1) in (15N)-3a is labelled and, hence, N(4) stems from 1, e.g. the azirine reacts via cleavage of the N(1)=C(3) bond. In MeCN at room temperature, the azacyclols 3 rearrange slowly to give monocyclic 2H,5H-imidazol-2-ones 4 (Scheme 3); the 15N-label in (15N)-4a is in position 1. Both reactions proceed via deep-seated skeletal rearrangements, most probably via ring-expansion/ring-contraction processes.

Ring-Transformations in the Reaction of 3-(Dimethylamino)-2,2-dimethyl-2H-azirines with 1-Substituted Imidazolidine-2,4,5-triones. Reaction of 1-substituted imidazolidine-2,4,5-triones (= N-substituted parabanic acids; 2) and 3-(dimethylamino)-2,2-dimethyl-2H-azirine (1) in iPrOH or MeCN at room temperature yields 5,6,7,7a-tetrahydro-3H-imidazo[3,4-a]imidazole-5,7-diones 3 (Scheme 1). By 15N-NMR studies, using (3-15N)-2a, it has been shown that only N(1) in (15N)-3a is labelled and, hence, N(4) stems from 1, e.g. the azirine reacts via cleavage of the N(1)=C(3) bond. In MeCN at room temperature, the azacyclols 3 rearrange slowly to give monocyclic 2H,5H-imidazol-2-ones 4 (Scheme 3); the 15N-label in (15N)-4a is in position 1. Both reactions proceed via deep-seated skeletal rearrangements, most probably via ring-expansion/ring-contraction processes.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Language:German
Date:1993
Deposited On:26 Dec 2013 09:46
Last Modified:05 Apr 2016 17:19
Publisher:Wiley-Blackwell
ISSN:0018-019X
Funders:Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung, F. Hoffmann-La Roche AG, Basel
Permanent URL: https://doi.org/10.5167/uzh-87454

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