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Isolation and structure of a new Sceletium alkaloid containing a dihydropyridone ring
Tetrahedron Letters No. 2, PP 131 - 132. QPergamon Press Ltd. 1979. Printed in Great Britain.
ISOLATION
AND STRUCTURE
Paul M. Gross Chemical
Previous of alkaloids
on _. S namaquense
studies
constitutes
ALKALOID
CONTAINING
*Peter W. Jeffs and Thomas M. Capps Laboratory, Duke University, Durham,
based upon several
sole representative which
OF A NEW SCELETIUM
have led to the isolation
ring systems ' including
of this structural
North
Carolina
RING
27706
and characterization
the base Sceletium
This report describes
of this ring system. the second member
A DIHYDROPYRIDONE
of a variety
A4 (1)' which
the characterization
is the
of a new base
class.
PMe
2
1 Investigation alkaloids
of the polar column residue
of S. namaquense
tive layer chromatography base,
[Dlznl -10,500",
loids.
at 6 6.75-6.80
Other assignable
6 3.42, an E-methyl DzO.
absorptions
'H nmr spectrum
characteristic resonances
of the compound
spectrum
the mass spectral
fragmentation
pattern
amide.
The foregoing
of the alkaloid
131
which
two c-methyl disappeared
three proton
signals
alka-
at
upon addition
of the alkaloid
at 3470 cm-' (NH) and 1675 cm-' (amide CO), the latter to the NH signal of a secondary
active
by high resolution
group of the mesembrine
included
spectrum
prepara-
optically
C ZOH26N203
showed a typical
at 6 7.5 which
of the infrared
of the nonphenolic Successive
a non-crystalline formula
of the 3,4_dimethoxyphenyl
in the proton
with consideration
chromatography
of a new component.
and silica gel yielded
signal at 6 2.50, and a singlet
In conjunction
was assigned
over alumina
the presence
which was shown to have the molecular
The 100 MHz
mass spectrometry. multiplet
by glc revealed
from the alumina
which
of
showed
signal in the nmr spectrum evidence
included
in conjunction
prominent
with
ions at m/e 314
132
No. 2
(M-CO) and 299 (M-HNCO) racemic
product
Comparison the synthetic biogenetic
led to the consideration
of this structure of the spectral
product
prediction
Acknowledgments.
of structure 2 for the new base.
has been synthesized
by Stevens
that this compound We are indebted
would
their structural
occur as a natural
to Dr. R. V. Stevens
a
and coworkers.3
(nmr, ms and ir) and chromatographic
and the new base established
Fortunately
(gc and tic) properties identity
and vindicates
of the
product.
for the synthetic
sample of Compound
References 1.
R. R. Arndt and P. E. J. Kruger, -Tet. Lett. 3237 (1970): Jeffs and A. T. McPhail, -J. Chem. Sot. (Perkin 11 ) 1098
2.
P. W. Jeffs, T. M. Capps, D. B. Johnson, J. M. Karle, N. H. Martin, and B. S. Rauckman, Ir_.a. -., 39, 2703 (1974): P. W. Jeffs, P. A. Luhan, A. T. McPhail, and N. H. Martin, Chem. Commun., 1466 (1971): F. D. Snyckers, F. Strelow, and A. Wiechers, Chem. Commun.,1467 (1971).
3.
R. V. Stevens,
(Received
P. M. Lesko, and R. Lapalme,
in USA 20 October
1978)
L. 3.
T. M. Capps, K. D. Hargrave, (1977).
Chem. 40, 3495 (1975).
P. W.
2
ISOLATION
AND STRUCTURE
Paul M. Gross Chemical
Previous of alkaloids
on _. S namaquense
studies
constitutes
ALKALOID
CONTAINING
*Peter W. Jeffs and Thomas M. Capps Laboratory, Duke University, Durham,
based upon several
sole representative which
OF A NEW SCELETIUM
have led to the isolation
ring systems ' including
of this structural
North
Carolina
RING
27706
and characterization
the base Sceletium
This report describes
of this ring system. the second member
A DIHYDROPYRIDONE
of a variety
A4 (1)' which
the characterization
is the
of a new base
class.
PMe
2
1 Investigation alkaloids
of the polar column residue
of S. namaquense
tive layer chromatography base,
[Dlznl -10,500",
loids.
at 6 6.75-6.80
Other assignable
6 3.42, an E-methyl DzO.
absorptions
'H nmr spectrum
characteristic resonances
of the compound
spectrum
the mass spectral
fragmentation
pattern
amide.
The foregoing
of the alkaloid
131
which
two c-methyl disappeared
three proton
signals
alka-
at
upon addition
of the alkaloid
at 3470 cm-' (NH) and 1675 cm-' (amide CO), the latter to the NH signal of a secondary
active
by high resolution
group of the mesembrine
included
spectrum
prepara-
optically
C ZOH26N203
showed a typical
at 6 7.5 which
of the infrared
of the nonphenolic Successive
a non-crystalline formula
of the 3,4_dimethoxyphenyl
in the proton
with consideration
chromatography
of a new component.
and silica gel yielded
signal at 6 2.50, and a singlet
In conjunction
was assigned
over alumina
the presence
which was shown to have the molecular
The 100 MHz
mass spectrometry. multiplet
by glc revealed
from the alumina
which
of
showed
signal in the nmr spectrum evidence
included
in conjunction
prominent
with
ions at m/e 314
132
No. 2
(M-CO) and 299 (M-HNCO) racemic
product
Comparison the synthetic biogenetic
led to the consideration
of this structure of the spectral
product
prediction
Acknowledgments.
of structure 2 for the new base.
has been synthesized
by Stevens
that this compound We are indebted
would
their structural
occur as a natural
to Dr. R. V. Stevens
a
and coworkers.3
(nmr, ms and ir) and chromatographic
and the new base established
Fortunately
(gc and tic) properties identity
and vindicates
of the
product.
for the synthetic
sample of Compound
References 1.
R. R. Arndt and P. E. J. Kruger, -Tet. Lett. 3237 (1970): Jeffs and A. T. McPhail, -J. Chem. Sot. (Perkin 11 ) 1098
2.
P. W. Jeffs, T. M. Capps, D. B. Johnson, J. M. Karle, N. H. Martin, and B. S. Rauckman, Ir_.a. -., 39, 2703 (1974): P. W. Jeffs, P. A. Luhan, A. T. McPhail, and N. H. Martin, Chem. Commun., 1466 (1971): F. D. Snyckers, F. Strelow, and A. Wiechers, Chem. Commun.,1467 (1971).
3.
R. V. Stevens,
(Received
P. M. Lesko, and R. Lapalme,
in USA 20 October
1978)
L. 3.
T. M. Capps, K. D. Hargrave, (1977).
Chem. 40, 3495 (1975).
P. W.
2