Chemistry. — "The liiscoiunaric Acids". By A. W. K. de Jong. 

 (Communicated at the meeting of May 27, 1922). 



Some time ago ^) I communicated tlint the product of illumination 

 of coumarin is not identical with hjdrodicoumarin of Fittig and 

 Dyson, as Clamkjian and vSilber had thought, but that it must have 

 another structure, because when treated with alkalis it does not 

 give a mono-basic, but a di-baslc acid. 



It is natural to su[){)Ose that the pi-oduct of illumijiation of coumarin 

 is formed from coumarin in the same way as n- and j5-truxillic 

 acid are foi'med from the forms of normal cinnamic acid by the 

 combination with formation of a tetramethylene ling between the 

 doubly bound C-atoms of the two molecules. 



As two molecules of normal cinnamic acid can combine in four 

 diiferent ways to a truxillic acid *) also the combinatioii of two 

 molecules of coumarin will give four different biscoumarins, which 

 will, as the truxillic acids, belong to two series according to the 

 arrangement of the C-atoms with unequal (1) or equal (II) atom- 

 groups next to each other in the tetramethylene ring. 



Of both structural formulae two different biscoumarins can exist 

 according to the situation of the coumarinrings on different sides or 

 on the same side of the tetramethylene ring. 



1) These proceedings Vol. XX, 875. 



2) These proceedings Vol. XX, 590. 



