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IX. 



STUDIES IN THE DIFLAVONE GROUP. 



III. — Derivatives of Dicoumaranone and of Diflavanone. 



By HUGH RYAN, D.Sc, and JOSEPH ALGAR, M.Sc, 

 University College, Dublin. 



Rend December 13, 1915. Published Makch 28, 1916. 



It has been shown by Ryan and O'Neill (Proa Royal Irish Acad., xxxii 

 (1915), B, p. 48) that dibenzylidene-diacetoresorcinol, which was prepared 

 by the condensation of benzaldehyde with diacetoresorcinol, can be converted 

 into an oily diacetate, and that the latter by interaction with bromine forms 

 a crystalline tetrabromide of dibenzylidene-diacetoresorcinol-diacetate. They 

 found that alcoholic potash converted the tetrabromide into diflavone, and 

 that probably at the same time there was formed a small quantity of 

 dibenzylidene-dicoumaranone. The reaction is similar to that which takes 

 place in the conversion of the dibrornide of resacetophenone-monoethylether- 

 monacetate into 3-ethoxy-flavone. [St. v. Kostanecki, A. Rozycki, and 

 J. Tambor, Ber., xxxiii (1900), p. 3410.] 



Since diflavone, which is nearly colourless, contains no auxochromic 

 radicals, it cannot function as a mordant dye. It is, therefore, of importance, 

 especially with reference to the relation between the colours of this group and 

 those of the corresponding members of the monoflavone group, to obtain and 

 examine derivatives of diflavone which contain auxochromic radicals. 



By the action of potash on an alcoholic solution of diacetoresorcinol and 

 anisaldehyde, Eijkman, Bergema, and Henrad (Chemisch Weekblad I (1905), 

 p. 453), prepared dianisylidene-diacetoresorcinol. The compound consisted 

 of golden-yellow needles, which melted at 204° C. We obtained by a similar 

 method elongated, orange, hexagonal crystals, which melted at 205-206° O, 

 and which we term a-dianisylidene-diacetoresorcinol in order to distinguish 

 it from an isomeric compound which we prepared under other experimental 

 conditions. 



B.l.A. PHOC, VOL. XXXIII., sect, b, [ 2 E I 



