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Bortrifluorid-katalysierte Umsetzungen von 3-Amino-2H-azirinen rnit Aminosäure-estern und Aminen


Hugener, Martin; Heimgartner, Heinz (1995). Bortrifluorid-katalysierte Umsetzungen von 3-Amino-2H-azirinen rnit Aminosäure-estern und Aminen. Helvetica Chimica Acta, 78:1823-1836.

Abstract

Boron-Trifluoride-Catalyzed Reactions of 3-Amino-2H-azirines with Amino-acid Esters and Amines After activation by protonation or complexation with BF3, 3-amino-2H-azirines 1 react with the amino group of alpha-amino-acid esters 3 to give 3,6-dihydro-5-aminopyrazin-2(1H)-ones 4 by ring enlargement (Scheme 2, Table 1). The configuration of 3 is retained in the products 4. With unsymmetrically substituted 1 (R1 # R2), two diastereoisomers of 4 (cis and trans) are formed in a ratio of 1:1 to 2:1. With beta-amino-acid esters 5 and 7, only openchain alpha-amino-imidamides 6 and 8, respectively, are formed, but none of the seven-membered heterocycle (Scheme 3). Primary amines also react with BF3-complexed 1 to yield alpha-amino-imidamides of type 9 (Scheme 4, Table 2). Compound 9b is characterized chemically by its transformation into crystalline derivatives 10 and 12 with 4-nitrobenzoyl chloride and phenyl isothiocyanate, respectively (Scheme 5). The structure of 12 is established by X-ray crystallography. Mechanisms for the reaction of activated 1 with amino groups are proposed in Schemes 6 and 7.

Abstract

Boron-Trifluoride-Catalyzed Reactions of 3-Amino-2H-azirines with Amino-acid Esters and Amines After activation by protonation or complexation with BF3, 3-amino-2H-azirines 1 react with the amino group of alpha-amino-acid esters 3 to give 3,6-dihydro-5-aminopyrazin-2(1H)-ones 4 by ring enlargement (Scheme 2, Table 1). The configuration of 3 is retained in the products 4. With unsymmetrically substituted 1 (R1 # R2), two diastereoisomers of 4 (cis and trans) are formed in a ratio of 1:1 to 2:1. With beta-amino-acid esters 5 and 7, only openchain alpha-amino-imidamides 6 and 8, respectively, are formed, but none of the seven-membered heterocycle (Scheme 3). Primary amines also react with BF3-complexed 1 to yield alpha-amino-imidamides of type 9 (Scheme 4, Table 2). Compound 9b is characterized chemically by its transformation into crystalline derivatives 10 and 12 with 4-nitrobenzoyl chloride and phenyl isothiocyanate, respectively (Scheme 5). The structure of 12 is established by X-ray crystallography. Mechanisms for the reaction of activated 1 with amino groups are proposed in Schemes 6 and 7.

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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:1995
Deposited On:04 Dec 2013 14:07
Last Modified:05 Apr 2016 17:12
Publisher:Wiley-Blackwell
ISSN:0018-019X
Funders:Stipendienfonds der Basler Chemischen Industrie zur Unterstützung von Doktoranden auf dem Gebiete der Chemie, Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung, F. Hoffmann-La Roche AG, Basel

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