C. C 28 Sterols
71
the same doubts as are other sterol isolations of that vintage. Without adequate checks on the homogeneity (glc, mass spectrum) of Bolker's crinosterol,
the authenticity of this substance should be left in abeyance.
5. 24f-METHYLCHOLESTA-7,22-DIEN-3ß-OL (5,6-DlHYDROERGOSTEROL,
α-DlHYDRO- Δ
7 '
22
-ERGOSTADIENOL)
The A
7 -analog of brassicasterol with known configuration (β) at C-24
is a well-recognized minor yeast sterol (Callow, 1931; Barton and Cox,
1948). Its only reported isolation from a marine source, however with indeterminate stereochemistry at C-24 (21), has been reported by Gupta and
Scheuer (1968) from the sea star Acanthaster planci and the sea cucumber
Holothuria atra.
6. 24-METHYLCHOLESTA-5,24(28)-DIEN-3J8-OL (24-METHYLENECHOLESTEROL,
CHALINASTEROL, OSTREASTEROL)
24-Methylenecholesterol (22) is widely distributed in marine organisms
and was known under a number of trivial names over the years. Idler and
Fagerlund (1955) recognized it as a major sterol in oysters (Ostrea gigas) and
clams (Saxidomus giganteus) and established its structure by unambiguous
synthesis from the 24-oxo compound via a Wittig reaction (Idler and Fagerlund, 1957). Bergmann and Dusza (1957) paralleled this work by isolating
24-methylenecholesterol (22) from the coelenterate Zoanthus proteus, by
partially synthesizing it from the 24-oxo compound; and by demonstrating
its identity with chalinasterol. Gupta and Scheuer (1969) showed it to be
esentially the sole sterol in a toxic coelenterate (Palythoa sp.) from Tahiti.
It is a minor constituent of the sterol mixture of some green and brown algae
(Ikekawa et al, 1968). It is the second most abundant sterol (20%) in the
brown algae (Laminaria digitata and L. faeroensis (Patterson, 1968). In red
algae (Gibbons et al, 1967; Idler et al, 1968) it seems to be rare.
It should be mentioned that 24-methylenecholesterol (22) is not exclusively
of marine origin. Knights (1967) in his definitive study of the sterol composition of oat seeds showed it to be present in the fourteen-component mixture.
21
22
71
the same doubts as are other sterol isolations of that vintage. Without adequate checks on the homogeneity (glc, mass spectrum) of Bolker's crinosterol,
the authenticity of this substance should be left in abeyance.
5. 24f-METHYLCHOLESTA-7,22-DIEN-3ß-OL (5,6-DlHYDROERGOSTEROL,
α-DlHYDRO- Δ
7 '
22
-ERGOSTADIENOL)
The A
7 -analog of brassicasterol with known configuration (β) at C-24
is a well-recognized minor yeast sterol (Callow, 1931; Barton and Cox,
1948). Its only reported isolation from a marine source, however with indeterminate stereochemistry at C-24 (21), has been reported by Gupta and
Scheuer (1968) from the sea star Acanthaster planci and the sea cucumber
Holothuria atra.
6. 24-METHYLCHOLESTA-5,24(28)-DIEN-3J8-OL (24-METHYLENECHOLESTEROL,
CHALINASTEROL, OSTREASTEROL)
24-Methylenecholesterol (22) is widely distributed in marine organisms
and was known under a number of trivial names over the years. Idler and
Fagerlund (1955) recognized it as a major sterol in oysters (Ostrea gigas) and
clams (Saxidomus giganteus) and established its structure by unambiguous
synthesis from the 24-oxo compound via a Wittig reaction (Idler and Fagerlund, 1957). Bergmann and Dusza (1957) paralleled this work by isolating
24-methylenecholesterol (22) from the coelenterate Zoanthus proteus, by
partially synthesizing it from the 24-oxo compound; and by demonstrating
its identity with chalinasterol. Gupta and Scheuer (1969) showed it to be
esentially the sole sterol in a toxic coelenterate (Palythoa sp.) from Tahiti.
It is a minor constituent of the sterol mixture of some green and brown algae
(Ikekawa et al, 1968). It is the second most abundant sterol (20%) in the
brown algae (Laminaria digitata and L. faeroensis (Patterson, 1968). In red
algae (Gibbons et al, 1967; Idler et al, 1968) it seems to be rare.
It should be mentioned that 24-methylenecholesterol (22) is not exclusively
of marine origin. Knights (1967) in his definitive study of the sterol composition of oat seeds showed it to be present in the fourteen-component mixture.
21
22