The study of daidzein derivatives provides further support to the conclusions already arrived at regarding the special features of partial methylation and demethylation in the isoflavone series. Partial methylation of daidzein gives a good yield of the 7-monomethyl ether (isoformononetin) and the formation of the isomeric formononetin could not be detected. The same 7-methyl ether is obtained most conveniently by the demethylation of daidzein dimethyl ether with hydrobromic acid and hydriodic acid. 5:7-Dihydroxy and di-methoxy isoflavones have also been examined with a view to compare them with corresponding flavones. 7-Methoxy-5-hydroxy isoflavone is obtained most readily by partial demethylation of dimethoxy isoflavone with hydriodic acid whereas chrysin dimethyl ether yields mostly chrysin under these conditions.

Typical examples from lichen acids illustrating the applicability of the methods of para and ortho oxidation are studied. They follow the schemes of biogenesis given earlier and are found to proceed satisfactorily, thus providing convenient methods of synthesis. The common origin of CH₃, CH₂OH, CHO, and COOH and also of a hydroxyl group is emphasised.

In the presence of potassium carbonate or potash, acetone forms an addition product with 2∶6-dimethoxy quinone. Its properties and reactions are described. They give evidence for the presence of an aliphatic hydroxyl group and a ketone carbonyl. The combination is considered to involve addition of the acetone molecule at the C=O group in the 4-position of the quinone. Methyl ethyl ketone also forms a similar addition compound. Other simplep-benzoquinones do not give this type of compounds.