The Catalytic Potential of 4-Guanidinylpyridines in Acylation Reactions

Autor:	Hendrik Zipse, Evgeny Larionov, Ingmar Held, Christian Bozler, Felicia Wagner
Rok vydání:	2009
Předmět:	Organic Chemistry Alkylation Medicinal chemistry Catalysis Acylation chemistry.chemical_compound chemistry Catalytic cycle Computational chemistry Pyridine Lewis acids and bases Solvent effects Triethylamine
Zdroj:	Synthesis. 2009:2267-2277
ISSN:	1437-210X 0039-7881
DOI:	10.1055/s-0029-1216830
Popis:	A series of 3-alkyl-4-guanidinylpyridines with variable alkylation pattern have been synthesized and characterized with respect to their catalytic potential in acylation reactions of alcohols. The ability of the substitution pattern to stabilize acylpyridinium cations, which act as critical intermediates in the catalytic cycle of pyridine-catalyzed acylation reactions, has been assessed at the MP2(FC)/6-31+G(2d,p)//B98/6-31G(d) level of theory and inclusion of solvent effects in chloroform using the PCM continuum solvation model. The most active 4-guanidinylpyridines are among those having the most electron-rich pyridine ring. The influence of the type and concentration of the auxiliary base on the catalytic activity has also been studied. While the change from triethylamine to N,N-diisopropylethylamine as the auxiliary base does not lead to a systematic increase or decrease in the catalytic rates, the complete absence of auxiliary base leads to a 27-fold reduction in reaction rate.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::e92feb567d7b54d4d6e7d4125ba097cc https://doi.org/10.1055/s-0029-1216830 Zobrazit plný text záznamu