F. Sterol Biosynthesis
83
The biosynthetic steps of sterol side-chain modification are actively being
investigated. In a recent study, for example, Knapp and co-workers (1971)
showed that the phytoflagellate Ochromonas
malhamensis
converts 24ethylidene sterols, e.g., fucosterol (30) into poriferasterol (28), which possesses a 24-ethyl group. The intermediate detailed steps remain to be determined,
but Knapp et al. (1971) showed that the efficiency of the conversion depended
on the geometry of the ethylidene group.
TABLE 2.1
MARINE STEROLS
mp (in
Text no.
Name (composition)
degrees)
[«1D
Reference
1
22-/ra/i5-24-Norcholesta- 138-140
-52
Idler et al. (1970)
5,22-dien-3j3-ol
(C 2 e H 4 2 0)
2
Cholesterol
147-148
-40
Tsuda et al. (1957a,
(C 2 7 H 4 e O)
1958a)
3
A
7
-Cholestenol
122-122.5
+ 4.3
Toyama and Takagi
(C 2 7 H 4 6 0)
0
(1953); Kind and
Meigs (1955)
4
22-Dehydrocholesterol
134.5-135.5 -56.9
Tsuda et al. (1960);
(C 2 7 H 4 4 0)
Tamura et al. (1964)
5
24-Dehydrocholesterol
117
-38.7
Fagerlund and Idler
(C 2 7 H 4 4 0)
(1957)
6
A
7
'
22
-Cholestadien-3j3-ol
123-124
-13.3
Gupta and Scheuer
(C 2 7 H 4 4 0)
(1968); Sakai and
Tsuda (1963)
8
Crustecdysone
243
+ 61.8
Jizba et al. (1967)
(C 2 7 H 4 4 0 7 )
9
2-Deoxycrustecdysone
No data
No data
Galbraith et al. (1968)
(C 2 7 H 4 4 0 6 )
10a
Marthasterone (C 2 7 H 4 2 0 3 ) —
—
Turner et al. (1971)
10b
Dihydromarthasterone
167-169
—
Turner et al. (1971)
(C 2 7 H 4 4 C3)
15
Scymnol (dihydrate);
120-123;
+ 34 ± 2 Bridgwater et al.
3α,7α,12α,24£,26,27190
(1962)
Hexahydroxycoprostane
(C 2 7 H 4 8 0 6 -2H 2 0)
17
Campesterol (C 2 8 H 4 e O)
158-159
-37
Nishioka et al. (1965)
18
Dihydrobrassicasterol
152-153
-47
Gupta (1967);
(C 2 8 H 4 8 0)
148-149
-55
Martinez et al.
(1967)
{continued)
83
The biosynthetic steps of sterol side-chain modification are actively being
investigated. In a recent study, for example, Knapp and co-workers (1971)
showed that the phytoflagellate Ochromonas
malhamensis
converts 24ethylidene sterols, e.g., fucosterol (30) into poriferasterol (28), which possesses a 24-ethyl group. The intermediate detailed steps remain to be determined,
but Knapp et al. (1971) showed that the efficiency of the conversion depended
on the geometry of the ethylidene group.
TABLE 2.1
MARINE STEROLS
mp (in
Text no.
Name (composition)
degrees)
[«1D
Reference
1
22-/ra/i5-24-Norcholesta- 138-140
-52
Idler et al. (1970)
5,22-dien-3j3-ol
(C 2 e H 4 2 0)
2
Cholesterol
147-148
-40
Tsuda et al. (1957a,
(C 2 7 H 4 e O)
1958a)
3
A
7
-Cholestenol
122-122.5
+ 4.3
Toyama and Takagi
(C 2 7 H 4 6 0)
0
(1953); Kind and
Meigs (1955)
4
22-Dehydrocholesterol
134.5-135.5 -56.9
Tsuda et al. (1960);
(C 2 7 H 4 4 0)
Tamura et al. (1964)
5
24-Dehydrocholesterol
117
-38.7
Fagerlund and Idler
(C 2 7 H 4 4 0)
(1957)
6
A
7
'
22
-Cholestadien-3j3-ol
123-124
-13.3
Gupta and Scheuer
(C 2 7 H 4 4 0)
(1968); Sakai and
Tsuda (1963)
8
Crustecdysone
243
+ 61.8
Jizba et al. (1967)
(C 2 7 H 4 4 0 7 )
9
2-Deoxycrustecdysone
No data
No data
Galbraith et al. (1968)
(C 2 7 H 4 4 0 6 )
10a
Marthasterone (C 2 7 H 4 2 0 3 ) —
—
Turner et al. (1971)
10b
Dihydromarthasterone
167-169
—
Turner et al. (1971)
(C 2 7 H 4 4 C3)
15
Scymnol (dihydrate);
120-123;
+ 34 ± 2 Bridgwater et al.
3α,7α,12α,24£,26,27190
(1962)
Hexahydroxycoprostane
(C 2 7 H 4 8 0 6 -2H 2 0)
17
Campesterol (C 2 8 H 4 e O)
158-159
-37
Nishioka et al. (1965)
18
Dihydrobrassicasterol
152-153
-47
Gupta (1967);
(C 2 8 H 4 8 0)
148-149
-55
Martinez et al.
(1967)
{continued)