138
WERNER BERGMANN
dependently made the observation, then unexpected, that cholesterol is
not the only, or even the principal, sterol of bivalves. Bergmann recognized the sterol as a di-unsaturated compound which he named ostreasterol. He subsequently found it to be identical with chalinasterol for
which structure (III, R = H) had erroneously been proposed (17).
The Japanese investigators named their compound conchasterol. Other
names such as pectosterol, meretristerol, shakosterol, magakisterol, and
most recently pincsterol were proposed for similar or different sterols
isolated from Japanese mollusks (136). In a reinvestigation of bivalve
sterols, Idler and Fagerlund were the first to recognize the presence of
24-methylenecholesterol (II, R = D) and in doing so solved some of
the more puzzling aspect of bivalve sterol mixtures (37). Subsequently
the identity of ostreasterol (chalinasterol) with 24-methylenecholesterol
was demonstrated (38).
In Table V the physical properties of synthetic 24-methylenecholesterol are compared with those of other bivalve sterols. It appears
reasonable to assume that in addition to ostreasterol, pectosterol, pincsterol, conchasterol, and meretristerol consist essentially of 24-methylTABLE V
DI-UNSATURATED STEROLS OF BIVALVES
Name
24-Methylenecholesterol
(synthetic) (38, 39)
24-Methylenecholesterol
(natural) (37)
Ostreasterol (chalinasterol) (17)
Pectosterol (140)
Pincsterol (141)
Conchasterol (138)
Meretristerol (142)
Brassicasterol
Shakosterol (143)
Magakisterol (144)
Sterol
m.p., °C.
145
142
147
134-137
137
133-134
135
148
147
153
[
-35
-42
-35
-45
—
-44
-60
—
-47
Acetate
m.p., °C.
135
136
135
137
134
145
145
152
157
150
MD°
-47
-42
-46
—
-44
—
-50
-62
—
-52
Acetate
Br 4
(m.p.,
°C.)
156-158
—
154-156
—
—
—
—
209-216
—
—
Benzoate
(m.p.,
°C.)
151-152
148-153
151-152
—
141
—
—
163
—
—
enecholesterol. The last two sterol mixtures with high-melting acetates
probably contain significant quantities of brassicasterol (II, R = F).
The presence of this sterol in mollusks has clearly been demonstrated
(136). Brassicasterol also appears to be the principal component of the
bivalve sterols shakosterol and magakisterol. It is of interest to note
that two of the identified bivalve sterols are di-unsaturated isomers of
the order C 2 8H 46 0 and that the third is the mono-unsaturated choles-
WERNER BERGMANN
dependently made the observation, then unexpected, that cholesterol is
not the only, or even the principal, sterol of bivalves. Bergmann recognized the sterol as a di-unsaturated compound which he named ostreasterol. He subsequently found it to be identical with chalinasterol for
which structure (III, R = H) had erroneously been proposed (17).
The Japanese investigators named their compound conchasterol. Other
names such as pectosterol, meretristerol, shakosterol, magakisterol, and
most recently pincsterol were proposed for similar or different sterols
isolated from Japanese mollusks (136). In a reinvestigation of bivalve
sterols, Idler and Fagerlund were the first to recognize the presence of
24-methylenecholesterol (II, R = D) and in doing so solved some of
the more puzzling aspect of bivalve sterol mixtures (37). Subsequently
the identity of ostreasterol (chalinasterol) with 24-methylenecholesterol
was demonstrated (38).
In Table V the physical properties of synthetic 24-methylenecholesterol are compared with those of other bivalve sterols. It appears
reasonable to assume that in addition to ostreasterol, pectosterol, pincsterol, conchasterol, and meretristerol consist essentially of 24-methylTABLE V
DI-UNSATURATED STEROLS OF BIVALVES
Name
24-Methylenecholesterol
(synthetic) (38, 39)
24-Methylenecholesterol
(natural) (37)
Ostreasterol (chalinasterol) (17)
Pectosterol (140)
Pincsterol (141)
Conchasterol (138)
Meretristerol (142)
Brassicasterol
Shakosterol (143)
Magakisterol (144)
Sterol
m.p., °C.
145
142
147
134-137
137
133-134
135
148
147
153
[
-35
-42
-35
-45
—
-44
-60
—
-47
Acetate
m.p., °C.
135
136
135
137
134
145
145
152
157
150
MD°
-47
-42
-46
—
-44
—
-50
-62
—
-52
Acetate
Br 4
(m.p.,
°C.)
156-158
—
154-156
—
—
—
—
209-216
—
—
Benzoate
(m.p.,
°C.)
151-152
148-153
151-152
—
141
—
—
163
—
—
enecholesterol. The last two sterol mixtures with high-melting acetates
probably contain significant quantities of brassicasterol (II, R = F).
The presence of this sterol in mollusks has clearly been demonstrated
(136). Brassicasterol also appears to be the principal component of the
bivalve sterols shakosterol and magakisterol. It is of interest to note
that two of the identified bivalve sterols are di-unsaturated isomers of
the order C 2 8H 46 0 and that the third is the mono-unsaturated choles-