28
Ζ. Isoprenoids
1" OH
AcO\^i\/^o
/%Η
68
The structure of the second constituent, 17-deoxy-22,25-holothurinogenin
(63b), was readily deduced (Chanley et al, 1966) by preparation of several
derivatives and by spectral comparisons.
A third holothurinogenin, griseogenin (69), was isolated in addition to the
known 22,25-oxido compound (63a) by Tursch et al (1967) from the Cuvier
OH
iiiinOH
ΗΟ'^ΧΞ^^
'% Η
69
OH
HO
ΗΟ
>ψ^ν Ν ^^\ < .
70
71
glands and the body wall of the sea cucumber Halodeima grisea. The key
degradation that led to structure 69 involved lithium aluminum hydride
reduction of the mono- or diacetate to a pentaol (70), which was cleaved by
periodic acid in aqueous methanol. The resulting volatile aldehyde was
identified as 4-methylpentanal (71). The nonvolatile ketoacetate 72a was
compared with authentic 72b upon acetylation. Its generation from 70
proceeds through the following plausible sequence.
Ζ. Isoprenoids
1" OH
AcO\^i\/^o
/%Η
68
The structure of the second constituent, 17-deoxy-22,25-holothurinogenin
(63b), was readily deduced (Chanley et al, 1966) by preparation of several
derivatives and by spectral comparisons.
A third holothurinogenin, griseogenin (69), was isolated in addition to the
known 22,25-oxido compound (63a) by Tursch et al (1967) from the Cuvier
OH
iiiinOH
ΗΟ'^ΧΞ^^
'% Η
69
OH
HO
ΗΟ
>ψ^ν Ν ^^\ < .
70
71
glands and the body wall of the sea cucumber Halodeima grisea. The key
degradation that led to structure 69 involved lithium aluminum hydride
reduction of the mono- or diacetate to a pentaol (70), which was cleaved by
periodic acid in aqueous methanol. The resulting volatile aldehyde was
identified as 4-methylpentanal (71). The nonvolatile ketoacetate 72a was
compared with authentic 72b upon acetylation. Its generation from 70
proceeds through the following plausible sequence.