Abstract
3, 4-Diethoxydiphenyl ether-6, 4′-dicarboxylic acid (XVIII), m.p. 245-247°, and its dimethyl ester (XIX), m.p. 106-108°, were synthesized in order to compare with substances corresponding to the diethoxydiphenyl ether-dicarboxylic acid, m.p. 265-267°, obtained by the oxidation of magnolamine tetraethyl ether, and its dimethyl ester, m.p. 112-113°. The melting points of the synthetic products were found to be similar to but lower than those of the products obtained by the oxidation of the natural substance. In order to obtain the corresponding diethoxy compound (XVIII) from 3, 4-dimethoxydiphenyl ether-6, 4′-dicarboxylic acid (II) by the demethylation of the latter with hydrobromic acid followed by ethylation, an attempt was made on the demethylation with hydrobromic acid and acetic acid by which 3, 4-dihydroxydiphenyl ether-4′-carboxylic acid (VI), in which the carboxyl group in the 6-position of (II) had liberated as carbon dioxide, was obtained, instead of the objective 3, 4-dihydroxydiphenyl ether-6, 4′-dicarboxylic acid (III).
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
