T. R.
S. J . P ATANKAR a n d N.
1604
The minor constituent, m.p.
obtained in the chromatography had
spectral properties in very close agreement with the reported values for (-)
commonly referred to as
(II),’
mellein. This compound was first isolated3 from carrots which had developed a bitter
taste during storage. Subsequently this has been isolated from the cultures of the fungus
Sporormia
and Sporormia
Cacc., Bomm and
The identity of our compound was confirmed by direct
The absolute configuration at is
The racemic
form of (II) has been synthesized.
comparison with authentic
R since the circular dichroism (in
6-methoxymellein.
at 270 nm is negative, as in
The major constituent of the plant which has m.p.
named kigelin. Its molecular formula
[a],-79.91 is new and has been
was confirmed by the mass spectrum.
The presence of a phenolic hydroxyl group was shown by the purple
with
and
its
in aqueous alkali. Its
i.r. and NMR spectra showed obvious similarities
with those of
(II). The NMR spectrum* of kigelin showed the presence
of two methoxyls, one aromatic hydrogen, an
unit as in
0
mellein and a chelated hydroxyl. The carbonyl group in kigelin appeared in the i.r. at
This was shifted to 1710 in obtained by methylation,
indicating the presence of a chelated hydroxyl.
1665 cm-‘.
The facile demethylation of
with aluminium chloride in ether to give kigelin supports this conclusion.’ These data
indicated that kigelin is a
groups in the aromatic ring.
gave
having two methoxyl
with potassium
This leads to structure
Oxidation of
acid identified as its
for
and
for kigelin. The absolute configuration at
follows
from the negative CD at 271 nm.
The methylene hydrogens at
of kigelin appear in
essentially as two lines
at 2.87 and
is clearly shown in DMSO-d, in which they appear as the typical AB part of an ABX
system. The multiplet at also shows more fine structure in
The second new compound isolated from the plant has m.p.
molecular formula was shown by its mass spectrum. Its
as a multiplet at 8
The non-equivalence of the
hydrogens
Its
and NMR
spectra showed striking similarities to those of kigelin. Treatment of the compound with
diazomethane for a short duration gave kigelin whereas more prolonged treatment gave
This leads to structure
or
for the compound. Compound
was obtained by the demethylation of Q-methylkigelin with excess boron trichloride.
is known to cleave very readily aromatic methoxyls adjacent to a ketone
Boron
group. Of the methoxyls at
and
the latter possessing a more electron-rich ethereal
*
NMR sp ectr a w er e r ecor d ed in
TMS. Sign a ls d escr ibed a r e: s, sin glet; d , d ou blet; m , m u ltip let.
u n less oth er w ise n oted a n d
va lu es a r e given in p p m r ela tive to
W. J .
E.
R. AUE, R.
a n d L. A.
J. Am. Chem.
a n d H. P .
J. Org. Chem. 33, 1577 (1968).
5036 (1957).
Experientia 22, 575 (1966).
H. L. SLATES , S. WE BE R a n d N. L. WENDLER , Chimia 21,468 (1967).
H. AR AKAWA , Bull. Chem.
L. H. a n d R. H. L OCKE R , J. Chem.
Japan
(1968).
2379 (1950).
R. H. F . M ANSKE a n d H . L. H O L ME S , J. Am. Chem.
F . M. DEAN, J .
a n d N.
67, 98 (1945).
L. E. H O U G H T O N, J . A. MAR TIN , R. B. MO R T O N, B.
Tetrahedron Letters 4153 (1966).
A. W. P R ICE