Corrosion inhibition by naturally occurringsubstances—I. The effect of Hibiscus subdariffa (karkade) extract on the dissolution of Al and Zn

Synthese und Konstitution des Skutellareins

Three highly oxygenated flavone glucuronides in leaves of Spinacia oleracea

Total synthesis of seco-lateriflorone

A new and convenient synthesis of the flavonols of the quercetagetin series is described. ω: 4∶6-Trimethoxy-phloro-acetophenone has been prepared by two independent methods. By persulphate oxidation it is converted into the 2∶5-dihydroxy compound. Allan-Robinson condensation employing this ketone yields products containing a hydroxyl group in the 6-position. Subsequent demethylation and methylation yields the flavonols and their fully methylated ethers. Besides quercetagetin and tangeretin which occur in nature, 6-hydroxy galangin and 6-hydroxy myricetin which have not yet been discovered in natural products, have also been synthesised.

Ryuzaburo Nodzu

Papers

XIV.—Anthoxanthins. Part X. The synthesis of gossypetin and of quercetagetin