Articles written in Proceedings – Section A
Volume 33 Issue 3 March 1951 pp 142-147
Chromic acid oxidation of teloschistin triacetate yields 4:5-diacetyl-7-
Volume 44 Issue 1 July 1956 pp 42-45
Teloschistin has been prepared from physcion, the essential stage being the ω-bromo compound obtained by the use of N-bromo-succinimide. The higher m.p. of 244–46° is now recorded both for the synthetic and for the natural sample purified through the acetate. Complete methylation of teloschistin requires the use of methyl iodide and silver oxide at the final stage.
Volume 46 Issue 5 November 1957 pp 343-348
On the consideration that stillopsidin is 5-hydroxybutein, butein trimethyl ether has been subjected to nuclear oxidation and final methylation to yield stillopsidin tetramethyl ether. Stillopsidin has now been prepared in better yields by an improved method. The product obtained by the partial demethylation of 2: 4: 5-trimethoxyacetophenone is shown to be 2: 5-dihydroxy-4-methoxyacetophenone which has been prepared by an unequivocal method from pæonol. Similarly an authentic sample of 2: 5-dihydroxy-4-methoxy-benzophenone has been prepared and shown to be the same as that obtained by the partial demethylation of 2: 4: 5-trimethoxybenzophenone. A synthesis of 2:4-dihydroxy-5-methoxyacetophenone has also been carried out.
Volume 49 Issue 4 April 1959 pp 234-240
2-Methylanthraquinones with the 1∶4-dihydroxy system are conveniently prepared by the persulphate oxidation of the intermediate benzoylbenzoic acids and subsequent ring closure. 2-Methylquinizarin, islandicin and cynodontin have been prepared by this method as typical examples.
Volume 51 Issue 6 June 1960 pp 296-300
A convenient synthesis, following suggested path of biogenesis, of catenarin and erythroglaucin has been made. It involves nuclear oxidation of the corresponding benzoyl benzoic acid. This reaction and the following ring closure give very good yields of catenarin dimethyl ether. Complete demethylation yields catenarin and partial demethylation erythroglaucin which can also be formed by the partial methylation of catenarin.