S. Andreae, E. Schmitz, J. Wulf
Mar 12, 1992
Citations
0
Influential Citations
9
Citations
Journal
European Journal of Organic Chemistry
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.