104505-57-9Relevant academic research and scientific papers
Ring Opening of N-(Tetraalkylamidinio)pyridinium Salts by Anions of CH-Acidic Methylene Compounds
Feith, Bernhard,Weber, Hans-Martin,Maas, Gerhard
, p. 3276 - 3296 (2007/10/02)
N-Carbeniopyridinium salts 2, 4, 14, and 18 offer three sites to nucleophilic attack; depending on the reactants, all three modes have been realized.With anions of CH-acidic methylene compounds, α-attack at the pyridinium ring followed by ring opening leads to azahexamethine merocyanines (8, 15, 23).In some cases, kinetically controlled reactions yield 1,4-dihydropyridines which isomerize thermally to give 1,2-dihydropyridines which undergo ring opening spontaneously.Also, nucleophilic attack at the cationic substituent of the N-carbeniopyridinium salts is possible as is indicated by the formation of push-pull olefins 11, 16 and of enol ether 12.
Dication Ethers, 11. - Ambidoselective Reactions of β-Ketoenolates with Dication Ethers
Feith, Bernhard,Weber, Hans-Martin,Maas, Gerhard
, p. 2123 - 2141 (2007/10/02)
When the bis(N,N,N',N'-tetramethylformamidinio) ether salt 5a is treated with the β-ketoenolates 7a-h, j or β-ketonitrile anion 7i in acetonitrile, electrophilic transfer of a tetramethylformamidino group occurs exclusively at an oxygen atom of the ambident anions, thus yielding uronium salts 8a-j.From the acyclic β-ketoenolates 7a-f, β-acylenol ether salts (E)-8a-f are obtained diastereoselectively.Also, electrophilic attack by the diimidazolinio ether salt 5b and the dipyridino ether salt 5c,d occurs exclusively at an oxygen atom of the dimedone anion (8k, 15, 18).From 5c and the anion of Meldrum's acid, olefin 16 is formed by C/C bond connection. - An X-ray structure analysis of (E)-8f was performed.
