Laboratory Methods of Organic Chemistry - Sciencemadness Dot Org

268 OXONIUM SALTS
probable formula for the pyroxonium salts :
Cl
O
I
N
/ \
C C-CHa
HC CH
A
H3C-C
C
HC
C-CH3 H3C-C
+2NH3
CH -H2O
C-CH3
+NHJ
COH
Pyroxonium
Chloride
COCH3
Methiodide
H V C H
COCH,
2 : 6-Dimethyl-4-methoxypyridine
Tertiary oxonium salts derived from oenzopyranole (chromanole)
occur in the anthocyanin series, the red and blue pigments of many
flowers and fruits (E. Willstatter, P. Karrer, R. Robinson).
HCl + H,0
H OH
Benzopyranole Benzopyrylium chloride
The anthocyanins are glucosides of polyhydric phenols and phenol
ethers having OH and phenyl as substituents in the pyran ring. These
glucosides can be regarded as derived from three types of sugar-free
anthocyanidins.
Cl
C H
6H
Pelargonidin chloride Cyanidin chloride
Delphinidin chloride has a further OH group in the position indicated.
The important relations between cyanidin, quercitin, catechin, and
luteolin should be studied from the point of view of plant physiology.