A. E. Everest 363 



The present author's idea that the anthocyans were reduction 

 products of flavone derivatives was deepened by consideration of the 

 work of Keeble, Armstrong and Jones {Roy. Soc. Pruc. 1918, B, 113). 



Working upon these ideas he carried out exjjeriinents that clearly 

 showed that by the careful reduction of flavone derivatives a series of 

 red pigments having the properties of anthocyanidins could readily be 

 obtained ; moreover, contrary to the almost generally accepted idea, he 

 showed that quite similarly glucosides of the flavone series yielded — 

 without intermediate hydrolysis — glucoside red pigments in every way 

 similar to anthocyanins. From these investigations the present author 

 put forward the scheme : 



OH 

 VOH HOY 



H " reauchon H O H +Tm5 



III. Flavone derivative. IV. Colourless or faintly V. Anthocyan pigment, 



coloured intermediate product. 



to represent the change from flavone derivative to anthocyan, and the 

 formula V as that of a typical pigment of the latter group (Everest, 

 Roy. Soc. Proc. 1914, B, 444). As further support for these conclusions 

 the work of Watson and Sen (J. Chem. Soc. 1914. 389) and Combes 

 {ComjJt. Rend. 1913, 157, 1003) were cited. 



Shortly after the appearance of the above mentioned paper by the 

 present author, Willstatter and his collaborators published a short but 

 important paper (Sitzher. k. Akad. Wiss., Berlin, 1914, xil. 402) describing 

 the continuation of the work on the isolation of pure anthocyans from 

 flowers and fruits. They had obtained in a chemically pure and crystal- 

 line condition the anthocyan pigments from no fewer than nine flowers 

 or fruits, all of which pigments proved to be glucosides, and by hydrolysis 

 of the glucosides obtained the colour components also chemically pure 

 and crystalline. They described the decomposition of the non-glucoside 

 pigments (anthocyanidins) by the action of warm alkalis, and the products 

 produced thereby. As the result of their work they put forward for the 

 anthocyan molecule a formula identical with that previously proposed 

 by the present author. They pointed out however that their results 

 did not allow them to finally decide between it (V) and VI. They 

 further concluded that the scheme previously put forward by the 

 present author (see above) should represent the passage of a flavonol 

 derivative to an anthocyan pigment, and additional support to this was 



