Regioselective synthesis of indolyldihydropyridines. A remarkable solvent effect

Article abstract of DOI:10.1055/s-1991-26587

The synthesis of 1,2-dihydro-2-(3-indolyl)-1-methylpyridines and 1,4-dihydro-4-(3-indolyl)-1-methylpyridines through the addition of indoles to pyridinium salts in various solvents is described. Selective preparation of 1,2-dihydropyridines is possible performing the reaction in methanol as the solvent, whereas the 1,4-isomers are preferentially formed in dimethyl sulfoxide.