C. Triterpenoids
29
74
ho
0
Ί
Ö
f Τ
Γ H-oH
J r°
IIIIHOH
• Λ
iiintOH
• J^^^^^^^
72
a: R = Η
b: R = Ac
A number of closely related aglycones have since been isolated from
several species of holothurians. Roller et al. (1969) reported three new genins
from the sea cucumber Bohadschia koellikeri—seychellogenin
(73a), koellikerigenin (73b), and ternaygenin (73c). The three compounds could be
\
llllllH
Η
73
a: R = Η
b: R = OH
c: R = OMe
readily interconverted, b -> a and b
c. The great ease of methylation of
koellikerigenin (73b) to ternaygenin (73c) suggested to the authors (Roller
et ai, 1969) that ternaygenin might be an artifact because the conditions under
which the C-25 hydroxy group is methylated are identical with those under
which the natural glycosides are hydrolyzed.
A fourth holothurinogenin, praslinogenin (74), was isolated by Tursch
et al. (1970) from the same animal, Bohadschia koellikeri. A comparison of
0\ /O^ <
/
ip^"
HIMOH
HO^^V^^^ Α Η
29
74
ho
0
Ί
Ö
f Τ
Γ H-oH
J r°
IIIIHOH
• Λ
iiintOH
• J^^^^^^^
72
a: R = Η
b: R = Ac
A number of closely related aglycones have since been isolated from
several species of holothurians. Roller et al. (1969) reported three new genins
from the sea cucumber Bohadschia koellikeri—seychellogenin
(73a), koellikerigenin (73b), and ternaygenin (73c). The three compounds could be
\
llllllH
Η
73
a: R = Η
b: R = OH
c: R = OMe
readily interconverted, b -> a and b
c. The great ease of methylation of
koellikerigenin (73b) to ternaygenin (73c) suggested to the authors (Roller
et ai, 1969) that ternaygenin might be an artifact because the conditions under
which the C-25 hydroxy group is methylated are identical with those under
which the natural glycosides are hydrolyzed.
A fourth holothurinogenin, praslinogenin (74), was isolated by Tursch
et al. (1970) from the same animal, Bohadschia koellikeri. A comparison of
0\ /O^ <
/
ip^"
HIMOH
HO^^V^^^ Α Η