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STUDIES IN THE DIFLAVONE GEOUP. 



IV. — On Diveratrylidene-Dicoumaranone. 



By HUGH EYAN, D.Sc, and MICHAEL J. WALSH, M.Sc, 

 University College, Dublin. 



Read December 13, 1915. Published March 2S, 1916. 



It has been shown by Eyan and O'Neill (Proc. Eoyal Irish Academy, xxxii 

 (1915), B, p. 48) that dibenzylidene-diacetoresorcinol interacts with acetic 

 anhydride and sodium acetate to form a diacetate, which readily adds on 

 bromine ; and that when the tetrabromide of the dihydroxydichalkone 

 diacetate is heated with alcoholic potash it is converted into diflavone. 



As diflavone contains no hydroxyl radicals, it cannot act as a mordant 

 dye. It seemed, therefore, of interest to attempt the preparation of hydroxyl- 

 derivatives of diflavone, with a view to elucidating the effect of the double 

 chromophore on the tinctorial properties of the group. 



From the marked auxochromic character of two hydroxyl radicals in the 

 ortho position, as in quercetin, alizarin, and several other dyes, it was to be 

 expected that one of the most important dyes derived from diflavone would 

 be a tetrahydroxy-diflavone (I) of the formula : — 



HO o 0H 



H0 _/ \-E/\/\/\C_/ \_oh 



\_/ I! 1*1 II \_/ 



HC\/\/\/CH 



CO CO 



A synthesis of this tetrahydroxy-diflavone was attempted, but as the 

 course of the reaction proceeded in a different manner from that observed by 

 Eyan and O'Neill in the case of diflavone, the final product which 

 we obtained was a derivative not of diflavone, but of the unknown 

 dicoumaranone. 



Diacetoresorcinol, prepared by the method of Eijkman, Bergenia, and 

 Henrard (Chemisch Weekblad, i. p. 453), from resorcinol diacetate and zinc 

 chloride, interacted with veratric aldehyde in the presence of alcoholic sodium 

 hydroxide to form diveratrylidene-diacetoresorcinol, and from the latter 

 compound by acetylation a diacetate was obtained. 



The yellow crystalline solid, which is formed when the tetrabromide of 



E.I.A. PROC, VOL. XXXm., SECT. B. [2 -F] 



