- Aqueous high-temperature chemistry of carbo- and heterocycles: Part 24 [1]. First demonstration of specific C-C bond scission of the pyridine ring. Reactions of piperidine, pyridine and some of their methyl derivatives in aqueous formic acid
-
In its reactions with the title compounds, formic acid variously acts as a formylating, methylating, and reducing agent. Both pyridine and piperidine are converted in significant amounts into 1-methyl-, 1-ethyl-, 1-propyl- and 1-pentyl-piperidines. Of the N-alkyl groups, isotopic labeling shows that only N-methyl derives from the formic acid, while the N-ethyl and N-propyl arise from heterocyclic ring C-C bond scission by retro-vinylogous-bis-aza-Aldol reactions. Detailed analysis of the products for pyridine, piperidine, and their 4-methyl derivatives, reacted separately and mixed, supports mechanisms in which a piperidine adds 1,2 to a pyridinium cation, or to a di- or tetra-hydropyridine, to initiate reaction sequences leading to the product slates found.
- Katritzky, Alan R.,Parris, Roslyn L.,Ignatchenko, Elena S.,Balasubramanian, Marudai,Barcock, Richard A.,Siskin, Michael
-
p. 220 - 230
(2007/10/03)
-