Anthocyanins and Anthocyanidins. 



161 



Observations concerning Related Pyrylium Compounds. 



In connection with other work, the present authors have prepared the 

 mother substance from which all anthocyans are derived (1), and also the 

 related compound (2) : — 



ci Ci ' 



o 



(1) I \ < (2) I 1~0" • 



c c 



I I 



H H 

 The compound (1) has been prepared as the oxonium chloride, as a double 

 salt with ferric chloride, and as the free base, whilst compound (2) has been 

 isolated as oxonium chloride, and as a double salt with ferric chloride. 



Observations 07i the Colour of Buds and Young Flotvers. 



A considerable number of plants, including auricula, apple, azalea, 

 polyanthus (red), primrose (red), violas, etc., were selected whose flowers 

 had well-marked anthocyan coloured petals when fully developed. Buds 

 were taken in each case from the same plant at intervals and examined, 

 until the fully developed flower had been reached. In some cases the 

 anthocyan did not develop until light fell on the petals, in others the 

 anthocyan (even quite deep shades) developed freely before the bud was 

 unfolded. Despite this, in nearly every case it was evident that, before the 

 anthocyan colour appeared, there was a stage in which the petals were 

 yellow or colourless, and contained dissolved substances which turned 

 yellow on exposure to ammonia. In the cases of some very deep coloured 

 flowers, e.g., black violas, the buds were highly coloured, even when 

 extremely small. , 



A number of flowers which when fully developed contain only flavonols 

 were likewise examined, including primrose (pale yellow), roses (various), 

 chrysanthemum, etc., but in no case could any intermediate anthocyan 

 formation be observed. 



Attempts to Extract Flavonols from Buds {before Anthocyans are present) and 

 Prodnce Anthocyan Colorations from them. 



Whilst the above observations showed that it was probable that flavonols 

 were formed before anthocyans, the authors desired to obtain further 

 proof of the presence of the flavonols. To this end they chose buds of a red 

 rose, and of a medium coloured mauve viola (Maggie Mott), as being 



VOL. XCII. — B. O 



