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First Identification of a Steroid Carboxylic Acid in Petroleum.

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band shifts. The apparent lack of coupling between H,H,
and H,H, is surprising, but another example of this is
known['1. The tabulated data are inconsistent with the
It is estimated that any
presence of form B: cf.
contribution from form B greater than 2% would have
been detected. Analysis of the NMR spectrum of the
corresponding 1,2-dicarboxylic acid (2) leads to a similar
conclusion (see Table).
Table. NMR spectra of compounds ( I ) , (21, and (6) (interpreted as
in refs. 12. 3, 6, 71). The spectra are independent of temperature.
Signals (T)
2.94 (2 Hid), J = 3.0 Hz
4.02 ( 2 Hid), J = 3.0 Hz
4.09 (2H) [a]
6.33 (6H/s)
H-3, H-8, form A
H-4, H-7, form A
H-5, H-6, form A
methyl ester protons
2.88 (2 Hid)
3.5 (2 H/br. s)
2.85 ('1
2.79 (s) [b]
3.75-4.40 ( 5 Him)
6.58 (3H/s)
H-3, H-8, form A
H-4-H-7, form A
carboxylic acid protons
Received: June 14, 1971 [Z 474b IE]
German version: Angew. Chem. 83,804 (1971)
First Identification of a Steroid Carboxylic Acid in
By Woygang K . Seqert, Emilio J . Gallegos, and
Richard M . Teeter"'
may result more from steric than from electronic factors
since the NMR spectrum (Table) of ( 6 ) [ 9 1shows that it also
occurs only in form A.
(la), R = COOH
( l b ) >R = CH,
aromatic protons
+ H-3, form A
methyl ester protons
That none of form B is in fact present is also suggested by
the reported inability of the dicarboxylic acid (2) to form
a cyclic anhydride under normal conditions[*]. In contrast,
benzocyclooctatetraene-7,8-dicarboxylicacid, which must
exist solely in form (3), readily forms a stable cyclic anhydride"!
We now report that the acid (2) can be induced to form a
cyclic anhydride in low yields when treated with ethereal
dicyclohexylcarbodiimide. In contrast with the anhydride
from acid ( 3 ) , this new anhydride is highly unstable and
polymerizes rapidly. Yet fresh samples, obtained with
difficulty, showed a parent peak in the mass spectrum and
had IR and NMR spectra consistent with the presence of
vinyl protons only (z 3.7-4.45 in C,D,/(CD,),CO). Since
the properties appear to exclude the obvious structure ( 4 ) ,
we are obliged to consider the apparently more strained
structure ( 5 ) as the only one consistent with the experimental observations. The apparent failure to stabilize by isomerization to form ( 4 ) is remarkable. The strong, apparently exclusive, preference for form A in the present examples
[l] G. Schroder, J . F . M . Oth, and R. Merinyi, Angew. Chem. 77,174
(1965); Angew. Chem. inlerna~.Edit. 4, 752 (1965); G. SchrGder and J .
F . M . Oth, Tetrahedron Lett. 1966,4083; J . F . M . 0 t h and J . M . Gdles,
ibid. 1968, 6259; S . M . Johnson, I . C . Paul, and G . S. D. King, J. Chem.
SOC.B 1970,643.
[2] F. A . L. Anet and L. A. Bock, J. Amer. Cheni. SOC.PO, 7130 (1968).
[3] F . A . L. Anet, A . J . R. Bourn, and Y. S t i n , J. Amer. Chem. Sac. 86,
3576 (1964).
[4] J . F. M . Oth, R. Merinyi, Th. Martini, and G . Schroder, Tetrahedron
Lett. 1966, 3087.
[5] D. E. Gwynn, G . M . Whitesides, and J . D. Roberts, J. Amer. Chem.
SOC.87, 2862 (1965).
[6] E. Grotenstein Jr., T C. Campbeli, and T Shibata, J. Org. Chem. 34,
2418 (1969).
[7] J . A . E l k M . Y Sargent, and F . Sondheimer, J. Amer. Chem. SOC.
92,973 (1970).
[S] D. Bryce-Smith and J . E. Lodge, Proc. Chem. SOC.1961, 332; J.
Chem. Soc. 1963,695.
[9] D. Bryce-Smith, A . Gilbert, and J . Grzonka, Chem. Commun. 1970,
No. 10
R = CH,D
= CH,-O-SO,-C~H,CH,
(If), R = COOCH,(CF,),H
( l g i . R = CH,CH,COOH
(14, R
(le), R
[a] Irregular singiet
[b] Shoulder.
Angew. Chem. internat. Edit. 1 Vol. 10 (1971)
In a recent publication['], we reported forty new classes
of carboxylic acids in a Californian petroleum of Pliocene
age (10 million years old). We now wish to report the
identification of 23,24-bisnor-5a-cholanic acid ( I a) in the
same oil.
A narrow fraction of carboxylic acids (fraction D-4"',
representing 1.6% of all acids and 0.04% of the petroleum)
was converted by parallel reductions to hydrocarbons and
deuterium-labeled hydrocarbons (in the position of the
original carboxylic acid group) via the alcohols and p toluenesulfonates using LiAIH, and LiAID, in the last
step[,]. The hydrocarbon and deuteriohydrocarbon samples were then further fractionated in parallel by silica gel
and gel permeation chromatography (GPC) using previously described techniques[4! Gas chromatography (GC)
of a selected G P C fraction (100-foot by 0.02-inch ID
capillary column, coated with OV 17) in combination with
mass spectrometry (AEI MS-9) led to the identification of
compounds (1b ) and ( I c), respectively, thus showing the
acid to have structure ( l a ) .
Proof of structure was obtained by: 1. Synthesis of 23,24bisnor-5 a-cholane (1 b) by Wolff-Kishner reduction of
3-oxopregn-4-ene-20 P-carbaldehyde and subsequent catalytic hydrogenation with PtO, in acetic acid. The resulting
mixture of ( I bj and the stereoisomeric 5 p-hydrocarbon
was separable by preparative GC(6 m by 6 mm O D column,
3% OV 17 on Gas-Chrom Q) and the products distinguishable by mass spectrometry; 2. Synthesis of (1 c) by
chromic acid oxidation of 3 P-hydroxy-23,24-bisnor-5
zcholanic acid to the corresponding ketone and subsequent
Wolff-Kishner reduction to give acid ( I a ) ; the latter was
converted[41 to deuterium-labeled hydrocarbon (1c) cia
alcohol ( I d ) and p-toluenesulfonate ( I e ) with LAID,.
Mass spectral fragmentation patterns and gas chromatographic retention times of synthetic labeled ( I c) and unlabeled ( I b) hydrocarbons were identical with those obtained from the naturally occurring acid ;3. The mass spectrum of synthetic ester (1f) was identical with that obtain[*] Dr. W. K. Seifert
Chevron Oil Field Research Company, P. 0. Box 1627
Richmond, California 94 802 (USA)
Dr. E. J. Gallegos and Dr. R. M. Teeter
Chevron Research Company
Richmond, California 94802 (USA)
ed on GC-MS of the original acid fluoroheptyl ester mixture['] at the retention time of ester (1f).
In addition, two stereoisomeric C,,-steroid carboxylic
acids were identified. Although structural proof is not
complete, present results suggest that they are 5a- (Ig)
and 5 B-cholanic acids.
The significance of this work is that these are the first polycyclic naphthenic carboxylic acids ever reported in petroleum as individual compounds; and on top of this they
possess biological precursor hydrocarbon skeletons and,
therefore, are geochemically significant. Animal bile acids
are considered to be the most likely precursors.
We consider it remarkable that an anion should be formed
B to the COOLi group, which leads to destabilization of
the ether linkage and thereby to a reversal of the Perkin
coumarin-benzofuran ring contraction. The reaction probably represents a route to hitherto inaccessible coumarins
and o-coumaric acid derivatives.
Elemental analyses, IR and NMR spectra were all compatible with the above formulations.
Received: May 13, 1971;
revised: July 16, 1971 [ Z 477 IE]
German version: Angew. Chem. 83, 755 (1971)
[I] B. Libis and E. Habicht, Belg. Pat. 733768 (1969), Geigy SA.
Received: July 26,1971 [ Z 475 IE]
German version: Angew. Chem 83, 805 (1971)
[l]Part ofthis work was presented at the Gordon Research Conference
of Organic Geochemistry, Holderness, New Hampshire, September
1970, and at the Pacific Conference of Chemistry and Spectroscopy,
San Francisco, California, October 1970.
[2] W K . Seijerr and R. M . Teeter, Anal. Chem. 42,180, 750 (1970).
[3] W. K . Sefert and W G. Howeffs,Anal. Chem. 41, 560 (1969).
[4] W K . Seferf, R . M . Teeter, W G . Howells, and M . J . R. Cantow,
Anal. Chem. 41, 1638 (1969).
[5] W K . Seifert and R . M . Teeter, Anal. Chem. 41,786 (1969).
Ring Expansion in the Benzofuran Series
[2] P. E. Pfeff.. and L. S. Silbert, J. Org. Chem. 35, 262 (1970); P. L.
Creger, J. Amer. Chem. SOC.89,2500 (1967).
[3] ?: Nakabayashi and K . Yamasaki, J. Pharm. SOC.Japan 74, 590
[4] P. Chuit and F. Bolsing, Bull. SOC.Chim. France 35, 82.
Diethylborylation and Determination of Water
with Activated Triethylborane
By Rokand Koster, Klaus-Ludger Amen, Hans BeIEut, and
Wolfgang Fenzl"
Protolyses of trialkylboranes to yield alkane and 0- or N alkylboryl derivatives according to
+ H-X
By Bernard Libis and Ernst Habicht"
2,3-Dihydro-6-methylbenzofuran-2-carboxylicacid"] is
converted into 2,3-dihydro-2,6-dimethylbenzofuran-2-car-
R=C,H,, C3H,, CH(CH3)2,CH,CH(CH,),
X = 0-alkyl, 0-aryl, 0-acyl, 0-SO,-alkyl, -0-SO,-aryl,
alkyl,, 0-N=C-aryl,,
N-alkyl,, N-allyl,, NH-aryl
boxylic acid ( 1 ) (for procedure see Ref. [2]).
If compound ( I ) is treated with 2.2 mol. equiv. of lithium
diisopropylamide at 0°C under N,, the reaction mixture
turns orange and a benzyl anion is formed. The dihydrofuran ring is cleaved between atoms 1 and 2, and acidification gives the known13]coumarin (2) as the major product.
The acid (3),m. p. 200"C, whose stereochemistry precludes
ring closure, appears as a minor product.
+ RH
proceed at differing rates, depending upon R and X. In
general, trialkylboranes react with carboxylic acids['' at
about room temperature. In contrast, temperatures of
160-170°C are necessary for reaction of alcohols[21or
phenols['], 170-200°C for dialkylamines'21, and about
100"C for alkane- and benzenesulfonic acids[3J.At these
temperatures certain functional groups can be reduced by
transiently formed B-H
bonds (dehydroboronation)
during the reaction.
We have found that protolyses of triorganoboranes can be
considerably accelerated by catalytic amounts of pivalic
acid or various pivalic acid derivatives :
X=e.g. (C,H,),B-0
H3 c
2,3-Dihydro-6-methylbenzofuran-2-carboxylicacid gives
the dicarboxylic acid ( 4 ) when treated according to Ref.
[2] and on adding CO,. Reaction of ( 4 ) with 3.3mol.
equiv. of lithium diisopropylamide furnishes the known'41
coumarincarboxylic acid ( 5 ) .
[*] Dr. B Libis and Dr. E. Habicht
Departement Forschung der Division Pharma
Ciba-Geigy AG
CH-4002 Base1 (Switzerland)
Triethylborane to which 0.1 to 1mol-% of pivalic acid has
been added reacts rapidly and quantitatively with water
or alcohols at room temperature, one of its ethyl groups
being eliminated as ethane.
H,O '2 (C2H5),BOB(C,H,)z
Cat. =(C,H,),B-O-CO-C(CH3)3
+ 2C2H.5
This reaction can be utilized for a very simple determination
of the water content of numerous hydrates of metal salts
(see Table) with the aid of triethylborane/diethylboryl
pivalate (b. p. 54"C/8 torr). The salts nearly always remain
Doz. Dr. R. Koster, Dr. K.-L. Amen, Dr. H. Bellut, and
Dr. W. Fenzl
Max-Planck-Institut fur Kohlenforschung
433 Miilheim/Ruhr, Kaiser-Wilhelm-Platz 1
Angew. Chem. internat. Edit. J Vol. I0 (1971) J No. 10
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acid, steroid, first, carboxylic, identification, petroleum
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