Algak, FoGARxy, & Ryan — Dichromone and Dibensytdichromone. 321 



Dibeuzyl-dichroinone crystallises in yellowish-white prismatic needles, 

 aggregated into clusters, melting at 223°-224:° C. It is insoluble in ether or 

 petroleum ether, sparingly soluble in benzene, xylene, or cold alcohol, and 

 readily soluble in hot alcohol, chloroform, acetone, or carbon-tetrachloride. 

 It is also insoluble in water or cold alkali. With warm alkali it goes into 

 solution, but on further heating a precipitate is formed, indicating decom- 

 position. In alcoholic solution it gives no colouration with ferric chloride. 

 It dissolves in concentrated sulphuric acid to a faint yellow solution, showing 

 an intense violet-blue fluorescence. 



C. — Summary. 



I. Dimethyl oxalate, diethyl oxalate, and ethyl formate condensed in each 

 ease with diacetoresorcinol-dimethylether to form a diketone. Each of these 

 diketones was converted by hydi'obromic acid into dichromone. 



II. Dibenzyldichromone was obtained similarly from the diketone 

 produced by the condensation of pheuylacetic ester with diacetoresorcinol- 

 dimethylether. 



III. The properties of dichromone and dibenzyldichromone resemble 

 tliose of chromone, and, like the latter, these substances give a characteristic 

 fluorescence in sulphuric acid solution. 



