2990 ERICH MOSETTIG AND ALFRED BURGER VOl. 52 scarcely affected. In parallel experiments with veratric aldehyde, only traces of alkali-soluble material were obtained; in the case of tetrahydroberberine, the two methoxyl groups remained intact. The ester group in piperonylic acid methyl ester was hydrolyzed only to a small extent. The method is not applicable to those substances which are extremely sensitive toward aluminum bromide ...
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