174 Proceedings of the Royal Irish Academy. 



On acetylation and bromination it forms the same diacetate-tetrabromide 

 as the j3-derivative. 



A mixture of 0-5 gramme of a-dibenzylidene-diacetoresorcinol, - 

 gramme of anhydrous sodium acetate, and 5 ccs. of acetic anhydride wa 

 heated for a few minutes to gentle boiling, cooled, mixed with water, and 

 extracted with chloroform. The chloroform solution was washed with dilute 

 sodium bicarbonate, and passed through a dry filter paper into a small dry 

 flask. After addition to it of a chloroform solution of 0'45 gramme of bromine 

 the colour of the latter rapidly became lighter without the evolution of 

 hydrobromic acid. After standing twelve hours the solvent was evaporated, 

 and the residue was recrystallized from boiling xylene. The yield was nearly 

 quantitative. The tetrabromide melted at 176-178° C, and a mixture of it 

 with the tetrabromide of the diacetate of /3-dibenzylidene-diacetoresorcinol 

 also melted at 176-178° C. The identity of this bromide with that previously 

 described by us (loc. cit.) was further confirmed by its conversion into 

 diflavone. 



On shaking 0"5 gramme of the tetrabromide with 7 - 8ccs. of semi-normal 

 alcoholic potash, the solid dissolved ; the colour of the solution changed from 

 yellow to red, and potassium bromide separated. When heated for a short 

 time on the water-bath, felted needles of diflavone wero obtained. The 

 crystals dissolved in concentrated sulphuric acid, giving a yellow-coloured 

 solution, which had the intense blue fluorescence characteristic of diflavone. 



3. Action of Hydrochloric Acid on a Solution of a- Dibenzylidene-diacetoresorcinol 



in glacial Acetic Acid. 



About 5 grammes of a-dibenzylidene-diacetoresorcinol were dissolved in 

 150 ccs. of boiling glacial acetic acid, and about 10 ccs. of concentrated 

 hydrochloric acid were added. The mixture was heated under a reflux 

 condenser to gentle boiling for several days, with occasional cooling and 

 saturation with gaseous hydrochloric acid. An equal volume of hot water 

 was added to the orange solution, which was cooled and filtered. The solid 

 was dried, and then recrystallized several times from chloroform and alcohol. 

 When dried at 110° O, it melted at 205° O, and gave on analysis the 

 following results : — 



01415 substance gave 0'4032 C0 2 and 0-0625 H 2 0, 

 corresponding to C 77'71, H 4-91, 

 C^H.A requires C 77'84, H 4-86. 

 S. Dibenzylidene-diatxtoresorcinol crystallizes in yellow diamond-shaped 

 crystals, which are sparingly soluble in boiling alcohol, and readily soluble in 

 warm chloroform. 



