177 



when they are on different sides, a new biscoumaric acid will be 

 obtained. 



The methylation of «-biscoumaric acid by diinethyisiilfate gives the 

 dimethylesler of the diniethylether crystallized into needles, melting 

 at 133° and sparingly soluble in ether. On boiling with alkalis 

 the dimethylether was obtained melting at 261° — 262°. Bkktram 

 and KüRSTEN ') found the melting point of this substance, obtained 

 by illumination of the methylether of coumaric acid, to be 

 260—262°. 



When the dimethylether is heated with the acetic acid anhydride 

 at 210°, the anhydride of the dimethylether of y-biscoumaric acid 

 was formed, which crystallized in pretty large bright yellow crystals 

 out of the anhydride of acetic acid, melting at 186° — 187°. The 

 dimethylether itself was obtained in fine needles melting at 234°. 



When the «-biscoumaric acid is heated with KOH the acid corre- 

 sponding to ^ cocaic acid was obtained, which separated in an 

 ether solution by addition of petrolether in rhomb-shaped crystals 

 melting 212°. As it whould be strange to give this acid a name 

 connected with coca, I propose to call it 5-biscoumaric acid. With 

 a similar treatment also the dimethylether of «-biscumaric acid gave 

 the same acid, which shows that the methylgroups are split off 

 through melting with KOH. 



These transformations of the «-biscoumaric acid, respectively the 

 dimethylether, are wholly analogous to these of «-truxillic acid. 



The dimethylester of the dimethylether of the biscoumaric acid 

 of the product of illumination of coumarin, for which I propose 

 the name of A-biscoumaric acid, melts at 112° — 113°; the dimethyl- 

 ether itself at 134°. 



By heating the dimethylether with acetic acid anhydride at 210° 

 and after evaporating the solvent in a glycerine bath at about 130° 

 a brown sirup was obtained, which did not crystallize. The acid 

 obtained by boiling the sirup with alkali crystallizes out of an ether- 

 petrolether solution in fine needles melting at 203°. On account of 

 its resemblance in structure with e truxillic acid I propose to call 

 this substance the dimethylether of s biscoumaric acid. This trans- 

 formation proves that the coumarin-rings of the illumination product 

 are situated on different sides of the tetramethylene ring and as 

 also «-biscoumarin possesses the same situation of the coumarin- 

 rings and the two substances are different, A-biscoumarin must have 

 the structure of fig. II and by the removing of a carboxylgroup 



1) Journ. f. pr. Ch. (2) 51, 323. 



