Biology Reference
In-Depth Information
HO
OH
HO
OH
HO
OH
HO
OH
HO
OH
O
OH
O
O
O
O
Hexahydroxydiphenoyl
(HHDP) group
Dehydrodigalloyl group
HO
HO
O
Macaranoyl group
HO
O
HO
OH
OH
HO
OH
O
O
HO
OH
HO
OH
HO
OH
HO
OH
HO
O
OH
HO
OH
O
HO
HO
O
O
O
O
HO
OH
O
O
Valoneoyl group
D
Tergalloyl group
HO
OH
HO
OH
HO
OH
HO
OH
HO
OH
HO
m
"
m
HO
O
O
OH
O
O
O
O
O
O
HO
OH
HO
HO
OH
p
m
O
OH
HO
m,m"
-D(OG)
2
O
O
O
m,p
-D(OG)
2
The HHDP group produced in the primary class of ellagitannins can
then be oxidized to dehydrohexahydroxydiphenoyl (DHHDP) group
(Fig. 1.1). The compounds that bear this DHHDP group are referred to as
“dehydroellagitannins” and exemplified by
inter alia
geraniin, terchebin
and furosinin. Among the special chemical reactivity features of the
DHHDP group, a cyclohexenetrione linked to a pyrogallol, are (1) the
aforementioned facile condensation with other compounds such as
ascorbic acid and
ortho
-phenylenediamine (
vide supra
) that furnish
ascorgeraniin and phenazine derivatives (Fig. 1.2) and (2) the
equilibrium in aqueous or alcoholic solutions between five- and six-
