16
/. Isoprenoids
perform some synthetic steps toward the aplysins. A direct experiment to
examine this point would be of interest because of its implications with
respect to terpene modification and to mollusk metabolism. In addition to
the five previously characterized compounds, L. okamurai yielded a compound
with the unexpected composition Ci4H 2 o0 5 Br2, mp 148.5°-149°, which—
mirabile dictu—proved to be identical with johnstonol of QsHaiC^B^Cl
composition (Sims et al, 1972).
In a recent paper on Laurencia constituents Irie's group (Suzuki et al, 1970)
isolated from L. glandulifera, which had previously (Irie et al., 1965b) yielded
laurene (29), the first example of an unrearranged farnesyl skeleton—however,
one with a different cyclization pattern leading to structural type 25b. The
compound was named spirolaurenone, colorless oil, [a] D —70.6°, and its
structure was shown to be 45 on the basis of spectral—largely nmr—analysis
and by chemical degradation.
Another spiro compound possessing the skeletal type 25c has been isolated
by Sims and co-workers (1971) from a Californian Laurencia, L. pacifica.
This skeletal type, although new among marine sesquiterpenoids, has a
45
46
Me
Br
)f
Br
><1 /Me S><^ ir
Me
Τα
Mcoh
1
C1
Br
Br
47
terrestrial representative in the sesquiterpene chamigrene (46), which Itô et al
(1967) had isolated from the essential oil of the leaves of a Formosan cypress
tree, Chamaecyparis taiwanensis, and which was synthesized by Tanaka et al.
(1967). The new algal sesquiterpenoid, pacifenol (47), differs from the known
constituents of the Japanese Laurencia species not only by its skeleton, but
by the fact that it contains covalent chlorine in addition to bromine. In fact,
pacifenol (47) appears to be the first authentic chlorine containing organic
compound to have been isolated from a marine source. This is indeed remarkable in view of the fact that the concentration of chlorine in seawater is
nearly 300 times as great as that of bromine. The structure of pacifenol was
secured by single-crystal X-ray techniques. The known compound laurinterol
(31a), previously isolated by Irie et al. (1966, 1970) from L. intermedia, was
also identified by Sims et al. (1971) as a minor constituent of L. pacifica.
16
1. Isoprenoids
perform some synthetic steps toward the aplysins. A direct experiment to
examine this point would be of interest because of its implications with
respect to terpene modification and to mollusk metabolism. In addition to
the five previously characterized compounds, L. okamurai yielded a compound
with the unexpected composition C14H2005Br2, mp 148.5°-149°, whichmirabile dictu-proved to be identical with johnstonol of C15H2103Br2CI
composition (Sims et al., 1972).
In a recent paper on Laurencia constituents Irie's group (Suzuki et al., 1970)
isolated from L. glandulifera, which had previously (Irie et al., 1965b) yielded
laurene (29), the first example of an unrearranged farnesyl skeleton-however,
one with a different cyclization pattern leading to structural type 25b. Th~
compound was named spirolaurenone, colorless oil, [aln -70.6°, and its
structure was shown to be 45 on the basis of spectral-largely nmr-analysis
and by chemical degradation.
Another spiro compound possessing the skeletal type 25c has been isolated
by Sims and co-workers (1971) from a Californian Laurencia, L. pacifica.
This skeletal type, although new among marine sesquiterpenoids, has a
Br
45
o
46
Br
Cl
Br
Me
47
terrestrial representative in the sesquiterpene chamigrene (46), which Ito et ale
(1967) had isolated from the essential oil of the leaves of a Formosan cypress
tree, Chamaecyparis taiwanensis, and which was synthesized by Tanaka et ale
(1967). The new algal sesquiterpenoid, pacifenol (47), differs from the known
constituents of the Japanese Laurencia species not only by its skeleton, but
by the fact that it contains covalent chlorine in addition to bromine. In fact,
pacifenol (47) appears to be the first authentic chlorine containing organic
compound to have been isolated from a marine source. This is indeed remarkable in view of the fact that the concentration of chlorine in seawater is
nearly 300 times as great as that of bromine. The structure of pacifenol was
secured by single-crystal X-ray techniques. The known compound laurinterol
(31a), previously isolated by Irie et ale (1966, 1970) from L. intermedia, was
also identified by Sims et ale (1971) as a minor constituent of L. pacifica.
/. Isoprenoids
perform some synthetic steps toward the aplysins. A direct experiment to
examine this point would be of interest because of its implications with
respect to terpene modification and to mollusk metabolism. In addition to
the five previously characterized compounds, L. okamurai yielded a compound
with the unexpected composition Ci4H 2 o0 5 Br2, mp 148.5°-149°, which—
mirabile dictu—proved to be identical with johnstonol of QsHaiC^B^Cl
composition (Sims et al, 1972).
In a recent paper on Laurencia constituents Irie's group (Suzuki et al, 1970)
isolated from L. glandulifera, which had previously (Irie et al., 1965b) yielded
laurene (29), the first example of an unrearranged farnesyl skeleton—however,
one with a different cyclization pattern leading to structural type 25b. The
compound was named spirolaurenone, colorless oil, [a] D —70.6°, and its
structure was shown to be 45 on the basis of spectral—largely nmr—analysis
and by chemical degradation.
Another spiro compound possessing the skeletal type 25c has been isolated
by Sims and co-workers (1971) from a Californian Laurencia, L. pacifica.
This skeletal type, although new among marine sesquiterpenoids, has a
45
46
Me
Br
)f
Br
><1 /Me S><^ ir
Me
Τα
Mcoh
1
C1
Br
Br
47
terrestrial representative in the sesquiterpene chamigrene (46), which Itô et al
(1967) had isolated from the essential oil of the leaves of a Formosan cypress
tree, Chamaecyparis taiwanensis, and which was synthesized by Tanaka et al.
(1967). The new algal sesquiterpenoid, pacifenol (47), differs from the known
constituents of the Japanese Laurencia species not only by its skeleton, but
by the fact that it contains covalent chlorine in addition to bromine. In fact,
pacifenol (47) appears to be the first authentic chlorine containing organic
compound to have been isolated from a marine source. This is indeed remarkable in view of the fact that the concentration of chlorine in seawater is
nearly 300 times as great as that of bromine. The structure of pacifenol was
secured by single-crystal X-ray techniques. The known compound laurinterol
(31a), previously isolated by Irie et al. (1966, 1970) from L. intermedia, was
also identified by Sims et al. (1971) as a minor constituent of L. pacifica.
16
1. Isoprenoids
perform some synthetic steps toward the aplysins. A direct experiment to
examine this point would be of interest because of its implications with
respect to terpene modification and to mollusk metabolism. In addition to
the five previously characterized compounds, L. okamurai yielded a compound
with the unexpected composition C14H2005Br2, mp 148.5°-149°, whichmirabile dictu-proved to be identical with johnstonol of C15H2103Br2CI
composition (Sims et al., 1972).
In a recent paper on Laurencia constituents Irie's group (Suzuki et al., 1970)
isolated from L. glandulifera, which had previously (Irie et al., 1965b) yielded
laurene (29), the first example of an unrearranged farnesyl skeleton-however,
one with a different cyclization pattern leading to structural type 25b. Th~
compound was named spirolaurenone, colorless oil, [aln -70.6°, and its
structure was shown to be 45 on the basis of spectral-largely nmr-analysis
and by chemical degradation.
Another spiro compound possessing the skeletal type 25c has been isolated
by Sims and co-workers (1971) from a Californian Laurencia, L. pacifica.
This skeletal type, although new among marine sesquiterpenoids, has a
Br
45
o
46
Br
Cl
Br
Me
47
terrestrial representative in the sesquiterpene chamigrene (46), which Ito et ale
(1967) had isolated from the essential oil of the leaves of a Formosan cypress
tree, Chamaecyparis taiwanensis, and which was synthesized by Tanaka et ale
(1967). The new algal sesquiterpenoid, pacifenol (47), differs from the known
constituents of the Japanese Laurencia species not only by its skeleton, but
by the fact that it contains covalent chlorine in addition to bromine. In fact,
pacifenol (47) appears to be the first authentic chlorine containing organic
compound to have been isolated from a marine source. This is indeed remarkable in view of the fact that the concentration of chlorine in seawater is
nearly 300 times as great as that of bromine. The structure of pacifenol was
secured by single-crystal X-ray techniques. The known compound laurinterol
(31a), previously isolated by Irie et ale (1966, 1970) from L. intermedia, was
also identified by Sims et ale (1971) as a minor constituent of L. pacifica.