Paper
Electrophile Aminierung von C‐H‐aciden Verbindungen mit 1‐Oxa‐2‐azaspiro[2.5]octan
Published Mar 12, 1992 · S. Andreae, E. Schmitz, J. Wulf
European Journal of Organic Chemistry
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Abstract
Electrophilic Amination of C-H-Acidic Compounds with 1-Oxa-2-azaspiro[2.5]octane The reactions of 1-oxa-2-azaspiro[2.5]octane (1, 3,3-pentamethyleneoxaziridine) with malonic (e.g. 4, 35) and cyanoacetic acid derivatives (e.g. 11, 1320) and other C-H acids [e.g. barbituric acid (6), Meldrum's acid, (diphenylmethyleneamino)-acetonitrile (26) 1-benzyl-3-hydroxy-4-methyl-1 H-pyrazol-5(4H)-one, and phenylbutazone (33)] have been studied. After the introduction of a 1-hydroxycyclohexylamino group at the acidic position, five different stabilisation reactions of the intermediate 2 could be classified. The most important one is an intramolecular nucleophilic attack to a nitrile group giving disubstituted 1,4-diazaspiro[4.5]decanones 2a. Their ring transformations (e.g. 2a 3) or the introduction of a second amino group at the same carbon atom (2a 3a) are further new reactions. Geminal diamino acid derivatives 3a thus obtained can be stable or rearrange to 3 (R1 NH2) or eliminate cyclohexanone (formation of 42) and/or ammonia (formation of 41 or 43). Amination of N-cyanoacetyl-protected amino acid esters (20, NHR = amino acid unit) with 1 yields cyclic dipeptide derivatives 41.
Electrophilic amination of C-H-acidic compounds with 1-Oxa-2-azaspiro[2.5]octane can produce stable or rearranged geminal diamino acid derivatives, with potential applications in pharmaceuticals and nutraceuticals.
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