56 Proceedings of the Royal Irish Academy. 



2. benzoylaeeto-3. methoxy-flavone and on prolonged heating (5 hours) into 

 diflavone. 



2. Benzoylaceto-3. metJioxy-flacone. 



C H -C C H CO 



Two grams of dibenzoylaceto-resorcinol-dimethylether were heated with 

 20 c.c. of hydriodic acid (sp. g. 1*7) to 135° C. under a reflux condenser 

 for an hour. The mixture was then well shaken with a solution of 

 sodium bisulphite, filtered and washed with water and alcohol. The 

 crystallised residue was dissolved in warm chloroform, filtered and mixed 

 with two volumes of alcohol. The solid was filtered, dried, and recrystallised 

 from boiling benzene. It melted at 238° C, and gave on analysis the 

 following results : — 



01539 substance gave 0-4259 CO, and 0-0629 H 2 0, 

 corresponding to C 7547, H 4 - 54. 

 C 2 ,H 1S 3 requires C 75-4, H 4-52. 



Eenzoylaceto-methoxy-flavone crystallises in faint yellow prisms which 

 are scarcely soluble in ether, alcohol, or petroleum ether, and readily soluble 

 in chloroform. It is sparingly soluble in cold benzene or boiling alcohol, 

 and the alcoholic solution gives a brownish-red coloration with ferric chloride. 



The crystals are coloured a faint yellow by concentrated sulphuric acid 

 in which they dissolve to a yellow solution which has a greenish fluorescence- 



Conversion of Dibenzoylaceto-resorcinol-dimetliylether into Diflaxone. 



Two grams of dibenzoylaceto-iesorcinol-dimethyether were heated to 

 135° C. for 5 hours with 20 c c. of hydriodic acid (sp. g. 1*7). The product 

 was freed from iodine by shaking with a solution of sodium bisulphite, 

 filtered, washed with water and alcohol. The solid was dissolved in warm 

 chloroform. The solution, after shaking with dilute potash, was filtered and 

 the chloroform was evaporated. The dry residue was recrystallised a couple 

 of times from boiling toluene. It softens at 275° C. and melts at 281-282° C. 

 to a brownish liquid. The pure diflavone obtained by this method differs 

 from that got from the dihydroxy-dichalkone only in the slightly higher 

 melting-point and in its behaviour towards sulphuric acid. 



The pure diflavoue dissolves in concentrated sulphuric acid to a faint 

 yellow solution which has a magnificent blue fluorescence, while that got 

 from the dichalkone containing some dibenzylidene-dicoumaranone gives 

 an orange solution in sulphuric acid, with a somewhat less intense blue 

 fluorescence. 



