[The effect of acids on dianisyl-pyridyl- and dipyridyl-anisyl-methanoles (author's transl)].

Different dianisyl-pyridyl- and dipyridyl-anisyl-methanoles react with sulfuric acid, hydrogen iodide or formic acid. Depending on the position of the methoxy groups, pyridine nucleus and acid demethylation or reduction occurs and 10-aryl-pyridol[1,2-alpha]-indole or 9-pyridyl-xanthenole-9, respectively, are formed as main or byproduct. UV-, IR- and 1H-NMR-spectra of the pyridonindoles are discussed.