B.—CHEMISTRY 49 
crystalline anthocyans prepared by the reduction of natural flavones or 
plant extracts containing them are nothing but the said flavones with 
a small proportion of adsorbed colouring matter of anthocyanidin type. 
It seems much more probable that the flavones and anthocyanins are 
independently synthesised, although perhaps from a common starting 
point. The existence of genetic factors which control the occurrence of 
anthoxanthins independent of that of anthocyanins is strong evidence in 
favour of this view. 
The anthocyanidins which have been isolated are the following : 
pelargonidin (XI), cyanidin (XII), peonidin (XIII), delphinidin (XIV), 
petunidin (XV), malvidin (XVI) and hirsutidin (XVII), represented as 
chlorides. All have been synthesised by unambiguous methods and the 
synthetic specimens have been carefully compared and identified with the 
Cl Cl OH 
a ——s 
OH NEO 
HO 
HO 
(XI) (XID) 
ice OMe Saran OH 
HO tt apa OH HO On < ou 
OH OH OH 
HO HO 
(XIII) (XIV) 
om OMe oF, OMe 
HO O a Nou HO? 20 —< You 
OH | ‘OMe 
OH \ 40H 
HO HO 
(XV) (XVI) 
OMe 3 
/OH OMe ae: 5 
HO 5 
(XVII) Numbering Scheme. 
_ hatural products. It will be observed that pelargonidin, cyanidin and 
_ delphinidin are the fundamental types, peonidin being a methyl ether of 
_ cyanidin and petunidin, malvidin and hirsutidin being, respectively, the 
_ mono-, di-, and trimethyl ethers of delphinidin. 
