Ryan and O'Nkill — Studies in the Diflavone Group. 53 



with benzaldehyde. On recrystallisation from benzene the substance 

 melted at 196-198°, and was identical in every respect with that prepared 

 by the action of aluminium chloride on dihydroxy-dichalkone-dimethylether. 

 As the amount of dihydroxy-dichalkone at our disposal was small, we 

 prepared the tetrabromide of the dimethylether in the hope that the inter- 

 action of it with aluminium chloride might enable us to form the diflavone 

 more conveniently. 



Tetrabromide of Dihydroxy-dichalkone-dimethyl ether, 

 C 6 H 2 (0 CH 3 ) 2 (CO . CHBr . CHBr . C 6 H 5 ) 2 . 



One gram of dihydroxy-dichalkone-dimethylether was dissolved in 

 10 c.c. of dry chloroform, and 0'85 gram of bromine was added to the 

 solution. The colour of the bromine disappeared rapidly without evolu- 

 tion of hydrobromic acid. After standing a short time alcohol was added, 

 and the crystalline solid which separated was filtered. It was recrystallised 

 from toluene, filtered when cold, washed with alcohol, and dried at 100° C. 

 for analysis. 



A determination of bromine in it by Stepanow's method gave the 

 following results : — 



0T800 substance on treatment with sodium and alcohol gave an 



N 

 amount of sodium bromide which required 10 - 1 c.c. — AgN0 3 for 



complete precipitation 



corresponding to Br 44'8, 



C 26 H 22 Br 4 4 requires Br 44 - 6. 



The tetrabromide crystallises from toluene in nearly colourless prisms, 

 which melt with decomposition at 185-186° O, and are only sparingly 

 soluble in alcohol, ether, ligroin, or chloroform. "When suspended in boiling 

 alcohol it gives no coloration with ferric chloride. 



On heating a solution of the substance in boiling xylene with anhydrous 

 aluminium chloride a dark green oily substance was formed, and from it we 

 were unable to isolate any crystalline compound. 



Having failed to obtain diflavone from the tetrabromide of the dimethyl 

 ether, we then prepared the tetrabromide of dihydroxy-dichalkone-diacetate, 

 in the expectation that the latter compound would react with alcoholic 

 potash to form diflavone. 



Tetrabromide of Dihydroxy-dichalkone-diacetate, 

 C 6 H 2 (OOCCH 3 ) 2 (CO . CHBr . CHBr . C 6 H 5 ) 2 . 

 A mixture of 1 gram of dihydroxy-dichalkone, 1 gram of anhydrous 



