186 Proceedings of the Royal Irish Academy. 



The second modification, j3-dianisylidene-diacetoresorcinol, was obtained 

 by the long-continued action of dilute aqueous sodium hydroxide on a mixture 

 of diacetoresorcinol and anisaldehyde. It consists of yellow diamond-shaped 

 crystals, which melt at 195-196° C, and since it, like the a-niodification, gives 

 a brownish-red coloration with alcoholic ferric chloride, it must contain at 

 least one hydroxyl radical in the ortho position to a keto group. Moreover, 

 the two compounds must contain unsaturated ketone groupings, since they 

 give red colorations with concentrated sulphuric acid. They are probably 

 stereoisomeric forms of dihydroxy-dimethoxy-dichalkone (I). The manner 

 in which we prepared the j3-derivative led us at first to assign it the chalkone- 

 flavanone formula (II), but the latter formula became untenable when we 



CH 



HO . C //\ C . OH 



CH 3 . H 4 C 6 . HC : CH . CO . C 'v^ J C . CO . CH : CH . C 6 H 4 . OCH 3 



CH 





 HO . /^/N CH . C 6 Hi . OCH3 

 CH3O . C 6 H 4 . CH : CH . CO . \)\ ) CH 2 



found that the two isomerides formed dihydroxydichalkone-diacetate tetra- 

 bromides which reacted with alcoholic potash to give the same crystalline 

 derivative. The product of this treatment must be regarded as a derivative 

 of dicoumaranone (III) rather than of diflavone, since its solution in 

 concentrated sulphuric acid has a deep purple-red colour. 



CH3O . CcH, . CH : c/ I in I \c : CH . C 6 H 4 . OCH 3 

 Co CO 



We also found that diacetoresorcinol condenses with anisaldehyde in 

 the presence of alcoholic hydrochloric acid to form anisylidene-2-p. 

 methoxy-cinnamoyl-3-hydroxy-4'-methoxy-tlavanone and dianisylidene-4'.4'- 

 dimethoxy-dinavanone. 



It has been commonly assumed that aldehydes condense to unsaturated 

 ketones, with the methyl radical of compounds having the general formula 

 GH 3 CO . X only in the presence of alkali, and that in the presence of an acid, 

 such as hydrochloric, this condensation does not take place. In the forma- 

 tion of diflavone derivatives, like dianisylidene-diflavanone and dibenzylidene- 

 dittavanone(Ryan and O'Neill, loc. cit.), it is evident that in the first stage of 

 the reaction, which is carried out by means of alcoholic hydrochloric acid, the 

 aldehyde must condense with the aceto radicals to form a diclialkone deriva- 



