functional groups of several examples of 1-alkyl-4(3)-(1H-azolylmethyl) pyridiniumsalts1 and 2 exemplifies a concomitant application of the arenoanalogy principle and the captodative effect in organic synthesis. A remarkably driving force by the nature of non-classical acceptor and donor heteroaromatic rings is observed upon the chemical behavior of the title compounds 1 and 2, modulating the susceptibility
An Advantageous Synthesis of 2-Substituted Benzimidazoles Using Polyphosphoric Acid. 2-(Pyridyl)-1<i>H</i>-benzimidazoles, 1-Alkyl-(1<i>H</i>-benzimidazol-2-yl)pyridinium Salts, their Homologues and Vinylogues
The title 2-substituted benzimidazoles are prepared by a highly efficient one-pot procedure, cyclodehydration of the corresponding accessible carboxylic acids and 1,2-arylenediamines, using polyphosphoric acid as the catalyst and solvent in a condensation of the type found in the Phillips benzimidazole synthesis. The method has been adapted and proved to be extremely useful for 1-alkyl-(1H-benzimidazol-2-yl) pyridinium tetrafluoroborates with a methylene and vinylene interannular moiety.
Synthetic applications of 2-cyano-1,2,3,6-tetrahydropyridines. 2. Synthesis of isodasycarpidone and related systems, the ervitsine skeleton and its benzo analog