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Organic Compounds in Fossil Plants (Voltzia brongniati Coniferales).

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[2] R. Appel and G. Eisenhauer, Z . anorg. allg. Chem. 310, 90
(1961).
[3] M . Lustig. C. L. Bumgardner, F. A. Johnson, and J. K . Ruff,
Inorg. Chem. 3, 1165 (1964).
[41 0. Glemser, H. W. Roesky, and P . R. Heinze, Angew. Chem.
79, 153 (1967); Angew. Chem. internat. Edit. 6, 179 (1967).
[5] H . W. Roesky and R. Mews, Angew. Chem. 80, 235 (1968);
Angew. Chern. internat. Edit. 7 , 217 (1968).
[6] E. Degener, H . Holtschmidt, and K . Swincicki, German Pat.
1167848 (1964), Farbenfabriken Bayer.
Organic Compounds in Fossil Plants
( Voltziu brongniurti, Coniferales)111
By H . Knoche, P . Albrecht, and G. Ourisson [*I
We recently reported our work on a fossil horsetail recovered
from a clay inclusion in the variagated sandstone of the
Northern Vosges (Trias, 2 x 108 years old) [31. The fossil plants
Voltria brongniarti (Coniferales) are also found in this same
sandstone[3]. Pieces of this fossil plant. about 1-5 cm long,
were collected in Hangviller (Moselle), care being taken
during collection to obtain as pure specimens as possible
and the working up being controlled by blank experiments.
Inorganic analysis gave a content of 6 0 % goethite,
FeZO3-H20 [41.
The dry fossil (2.6 kg) was ground and extracted with a 3 : l
benzene-methanol mixture (3 1) under the action of ultrasound. After centrifugation, decantation, and removal of the
solvent by distillation, there remained 42 mg (16 ppm) of
residue. The hydrocarbon fraction (3 mg, 1 . 2 ppm) was
isolated by column chromatography on silica gel; it was
crystalline and was shown by its gas chromatogram[5J to
consist almost wholly of one component. This substance was
identified as n-CZ8H58 by gas chromatography o n filled and
capillary columns [61,by inclusion in molecular sieves (Linde
5 A), and by the mass spectrum. n-Octacosane has not
previously, to our knowledge, been found as chief component
of the cuticular wax of a plant. As is well known, it is mainly
the odd-numbered hydrocarbons that occur in such waxes,
and furthermore as mixtures of homologs; in conifers nonacosane, C29H60. occurs most frequently, alongside hydroxy
esters and alcohols 17981.
We regard it as extremely unlikely that Voltzia, alone among
the conifers, contained an almost homogeneous even-numbered hydrocarbon, and we conclude that we are dealing with
a transformation product. It is not possible to study directly
what its precursor in Voltziu was, since this plant is extinct.
Of extant conifers the family Taxodiaceae is the most closely
related [91. We have therefore studied the wax of two members
of this family in the hope of identifying possible precursors
of the n-octacosane. In the wax of Cryptomeriajuponica Don.
only 10-nonacosanol was found -this is a widely distributed
constituent of many conifer waxes; it can hardly be considered as precursor of the octacosane. However, the wax of
Taxodium distichurn Rich. contains I-octacosanol as well'as
10-nonacosanol. The former alcohol was previously found
only in the wax of one other conifer, Gingko biloba L. [lo].
W e presume that n-C~sH58 was formed in the fossil by
reduction of the primary alcohol n-Cz7H55-CH20H; 10nonacosanol either was not present or was degraded in a n
unknown way. In this connection it is interesting that, according to Hoering, octadecanol is reduced to octadecane
simply by heating it with sedimentary rocks [111.
Received: June 4, 1968
[Z 806 IE]
German version: Angew. Chem. 80, 666 (1968)
[*] Prof. G. Ourisson, Dr. H. Knoche, and P. Albrecht
Universite de Strasbourg
Laboratoire attache au C.N.R.S.
1, rue Blaise Pascal, Strasbourg (France)
Angew. Chem. internat. Edit. J Vol. 7 (1968) / No. 8
[l] Part 11. - Part I: [2]. This work was carried out as part of the
research program D.G.R.S.T. No. 64-FR-058. - We thank
L. Grauvogel and J. C. Gall for help in collecting the fossils, and
Dr. P. Witz (Geigy, Basel) and G . Teller (Strasbourg) for measuring the mass spectra.
121 H . Knoche and G. Ourisson, Angew. Chem. 79, 1107 (1967);
Angew. Chem. internat. Edit. 6, 1085 (1967).
[3] W. P . Schimper and A. Mougeot: Monographie des plantes
fossiles du grks bigarre de la chaine des Vosges. Wilhelm Engelmann, Leipzig 1844.
[4] We thank S.N.P.A., Pau (France), for carrying out the
analysis.
[5] Conditions: Perkin-Elmer 226 gas chromatograph, 1.5 ?Ao
SE-30 on Aeropack 30, 80/100 mesh, 1.80 m long, diam, 3 mm,
program 6.25 "C/min, 100-290 "C, 30 ml He/min.
[6] Capillary column: 0.5 mm, SE-30, 240°C, 6.2 ml He/min.
Retention times: benzene 3.4 min; n-C~sH58,1 5 min.
[7] H . Ageta, J. pharmac. SOC.Japan (Yakugakuzasshi) 79, 47
(1959); Chem. Abstr. 53, 100310 (1959).
[ 8 ] K. Stransky, M . Streibl, and V. Herout, Collect. czechoslov.
chem. Commun. 32, 3213 (1967).
[9] J. C . Gall, personal communication.
[lo] H . Ageta, J. pharmac. SOC.Japan (Yakugakuzasshi) 79, 58
(1599); Chem. Abstr. 53, 10032c (1959).
1111 T. C. Hoering and R . M. M . Mitterer, Abstr. Annual. GSA
and Assoc. SOC.Joint Meeting, New Orleans 1967, p. 99.
Bis(tricarbonylcyclopentadienylchromium),
a Catalyst for Selective Hydrogenation
By A . Miyake and H . Kondo[*]
Tricarbonylcyclopentadienylhydridochromium ( I ) is converted by conjugated dienes at room temperature quantitatively into bis(tricarbonylcyclopentadieny1chromium) (2).
The conjugated dienes are hydrogenated in the process, e.g.
isoprene to 2-methyl-2-butene.
We also obtained (2). in ca. 80 % yield from bis(cyc1opentadienyl)chromium, by the following reaction, without the
need to isolate ( I ) :
I n contrast to dienes with conjugated double bonds, olefins
with isolated -C=C- bonds are totally unreactive towards
( I ) . Since (I) is regenerated from (2) by hydrogenrll, (2)
can with advantage be used as catalyst for selective hydrogenation. Some examples are given in Table 1. Characteristics for hydrogenation catalyzed by (2) are the following:
I. Isolated double bonds are not hydrogenated.
2. Double bonds d o not migrate.
3. Hydrogenation occurs smoothly above 7OoC and at Ha
pressures > 50 atm, but also slowly at room temperature or
atmospheric pressure.
4. Except for sterically hindered dienes, the hydrogen is
added preferentially at the ends of the conjugated system.
63 1
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