vj 



CONSTITUTION OF ANTHOCYANINS 



79 



Formula II was discarded because, if such a formula were correct, 

 it should be possible to obtain a substituted benzophenone, for example, 

 maclurin 1 , as a product from cyanidin, and this was not found to be 

 the case. 



Willstatter then suggests that the anthocyanidins and flavones are 

 related in the following way : 



Flavones Anthocyanidins 



Luteolin, karnpherol and fisetin C 15 H 10 6 -* pelargonidin C 15 H 10 5 

 Quercetin C 15 H 10 7 -* cyanidin C 15 H 10 6 



Myricetin C 15 H 10 8 -* delphinidin C 15 H 10 7 



that is, that each anthocyanin is derived from a flavone by reduction. 

 The formulae eventually suggested for the chlorides of cyanidin, 

 pelargonidin and delphinidin are as follows: 



OC1 



OH 



OC1 



OC1 



HO 



\ 



HO C 

 H 



Cyanidin chloride 



HQ 



Pelargonidin chloride 



Delphinidin chloride 



whereas myr-tillidin, oenidin and malvidin are represented as methyl 

 derivatives of delphinidin : 



OCl 



OCl 



OH 



OCl 



HO/V 



CHO 



OH 



HO 

 Myrtillidin chloride 



HO 



Oenidin chloride 



HO 

 Malvidin chloride 



Willstatter also brings forward, as additional evidence in favour 

 of these constitutional formulae, the preparation, artificially, of cyanidin 

 from quercetin (see p. 124). 



1 Maclurin is a pentaoxybenzophenone occurring in Morus tinctoria; 

 is represented as : 



HO OH 



>OH 



constitution 



HO CO 



