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V. 



STUDIES IN THE DIFLAYOXE GEOUP. 



I. — DlFLAYONE. 



By HUGH RYAN, D.Sc, ane Miss PAULINE O'NEILL, B.Sc, 

 University College, Dublin. 



Read Jaxuakt 25. Published April 26, 1915. 



The best known and the most widely distributed of the plant dyes 

 are those which are derived from flavone, or from the closely related 

 substance, flavonol. 



These dyes are, however, of a light yellow, or a yellow colour; and in 

 no case is the colour of a flavone, or of a flavonol, of a deeper tint than 

 yellow. 



There are, however, several natural red dyes, the constitutions of which 

 have not yet been determined : and in this connexion it seemed to us of 

 interest and importance to prepare substances containing a condensed form 

 of two flavone rings with a view to determining the effect of such a 

 structure on the depth of the tint of the compound. 



Thus from tlavone, flavanone, flavonol, and their parent substance chromone 



CO 



Flavanone. 



