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Biological Precursors and Genesis of Tyrian-Purple.

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CH,, C,H,, (CH,),CH, or (CH,),C, a sharp doublet, a
broad doublet, an unresolved broad signal, two poorly
resolved doublets, and a very sharp doublet are observed
at room temperature. This result can be simply explained
on the basis of the calculated relative energies of the possible
conformations of the molecule.
Introducing a methyl group at C-5 [compound ( I c ) ]
greatly alters the ratio of the conformers that differ in
arrangement around N-3. We call such an indirect conformational interaction a "gear" effect. In general, this
effect is found when the ratio of the conformers differing in
arrangement at atom 'a' is altered by the substituents on
atom 'c', the effect operating through and beyond atom
'b'. It may well contribute to an understanding of several
hitherto unsolved conformational problems.
Lecture at Hamburg (Germany) on June 11,1971 [VB 313 I€]
German version: Angew. Chem. 83,808 (1971)
Biological Precursors and Genesis
of Tyrian-Purple
By Herbert Fouquet and Hans-Joachim Bielig (Lecturer)[*'
It has been known for some time that indigo''] and 6,6'-dibromo indigo['' are major constituents of the ancient dye
Tyrian purple (red = purpura blatta, blue = purpura hyacinthina, and violet-red =purpura dibapha) from gastropod
mulluscs (Murex, Purpura, and other species). Living
gastropod mulluscs contain no indigoid dyes however.
They are formed, as previously assumed, by the action of
atmospheric oxygen and light on the autolyzed hypobranchial glands. An enzyme (purpurase) also plays an
important role in this transf~rmation[~"~.Letellier's
attempts at isolating chromogens from Purpura lapillus
Lam. (Atlantic)151yielded two photolabile components
(water-soluble leuco- and ether-soluble chlorolapillin),
which afford dyes at different rates, in addition to photostable alkali-soluble xantholapillin. The analog of leucolapillin obtained from the hypobranchial glands of Murex
brandaris or M . trunculus L. (Mediterranean) can be
separated into one or two prochromogens which on acid
hydrolysis afford sulfate, or sulfate and a thiol, as well as
indigoid and bromoindigoid dyes[61.
We[71have now been able to establish that four chromogens
are always present (average total 1.2 mg/gland, in the ratio
(1):(2):(3) :(4)~4.5:0.5:3:2) in methanol extracts of
Murex trunculus and usually only one of these (up to 0.6 mg
(4)/gland) in extracts of M . brandis, M . erinaceus, and
P . haemastoma. The colorless water-soluble crystallates of
the chromogens were isolated in pure form by combination
of gel chromatography and thin-layer chromatography.
0- so:
KO
mR
0- sop
Br
KO
H
H
(I), R
(2). R
['I
= H
f3), R = H
= SCH,
(4). R
= SOZCH3
( 5 ) . R = SCH,
Dr. H. Fouquet and Prof. Dr. H.-J. Bielig
Institut f i r Biochemie der Universitat
66 Saarbriicken 11
816
Their structures, ( I ) to ( 4 ) , were established by elemental
analysis, and UV, mass, and NMR spectroscopy. Compound ( 5 ) , which is missing in this series, was discovered
independently in Dicathais orbita (Pacific Ocean)[81.
On treatment with Raney nickel in ethanol, compounds
(2) and (4) are converted into ( I ) either directly or via (3).
Hydrolysis with hydrochloric acid affords sulfate [like (1)
and (311 and methanethiol (detected as Hg thiolate by
gas chromatography) corresponding to the cleavage observed with phalloidin and ~ a m a n i t i n [ Besides
~~.
indigo
and 6,6'-dibromoindigo, the analogous indirubins and
other known red 2,3'-coupled indigoid dyes are formed.
The chromogens (1) and (3) react anaerobically in the dark
at pH = 7.4 with the purpurase recognized as aryl sulfatase
to give indoxyl and 6-bromoindoxyl (as indolinones)
respectively, which afford aerobically in the dark only
indigo and 6,6'-dibromindigo taking up 1 mol O,/mol dye.
The chromogens (2)and ( 4 ) , on the other hand, react aerobically with aryl sulfatase in the dark to give the green
ether-soluble quinhydrones (corresponding to Letellier's
chlorolapillin) of 2-methylthioindole and 2-methanesulfonyl-6-bromo-indoxyl and their oxidation products (indoleninones). The last-named can be precipitated as the epoxidetype compounds ( 5 ) by treatment with diazomethane. In
daylight, the green intermediates undergo photolytic
cleavage of the S-components (to dimethyl sulfide or
secondary methanethiols) to give exclusively the same dyes
as ( I ) and (3). A total of only 0.5 mol O,/mol dye is
consumed in this combined dark- and light-reaction. If
conversion of the chromogens is carried out in the presence
of isatin or 6-bromoisatin [(7), Latellier's xantholapillin] also found in purpura glands, formation of
the corresponding indirubins additionally takes place.
When the chromogen (4) is irradiated in the solid phase
with 254-nm light it undergoes quantitative photooxidation to compound (7), whereas the chromogen (2) is not
affected.
&R
(Br)
(6). R = SCH,, SO,CH,
0
It can be concluded from the above findings that the ancient
dye purpura blatta originates predominantly from the
chromogen ( 4 ) , i. e. from purpura gastropod molluscs of
[l] A . de Negri and G . de Negri, Gazz. Chim. Ital. 1875,473.
[2] P . Friedliinder, Angew. Chem. 22,992,2494 (1909).
[3] Summary in 0.u. Fiirth: Vergleichende chemische Physiologie der
niederen Tiere. G . Fischer-Verlag, Jena 1903, p. 373f.
[4] V. Ersparner, Pubbl. Staz. Zool. Napoli 20.91 (1941)
[5] A . Letellier, Arch. Zool. Exper. 8, 361 (1890).
[6] S. Bouchilloux and J . Roche, Bull. Inst. Octanogr. [Monaco] Nr.
1054 (1955).
[7] H. Fouquet, Dissertation, Universitat Saarbriicken 1970; cf. also
J . Malaszkiewicz, Dissertation, Universitat Saarbriicken 1967.
[8] ' J . 7: Baker and M . D.Sutherland, Tetrahedron Lett. 1968,43.
[9] H. Faulstich and T h . Wieland, Liebigs Ann. Chem. 713, 186 (1968);
T h . Wieland and U . Gebert, ibid. 700, 157 (1966).
Angew. Chem. internat. Edit. 1 Vol. 10 (1971) / No. I 1
the Brandaris type. Purpura hyacinthina preferentially
arises from ( I ) and ( 3 ) , i. e. from the Trunculus type, and
purpura dibapha from the chromogens of both types by
double dyeing. The varied fastness to light was determined
by the amount of indirubins produced.
Lecture at Tubingen on July 2, 1971 [VB 315 IE]
German version: Angew. Chem. 83,856 (1971)
Modes of Action of Antibiotics
By Josef Schmidt - T horn$']
In the lecture five important groups of antibiotics, classed
according to mode of action, were discussed :
1. Antibiotics which inhibit synthesis of the cell wall. The
first and foremost of this group are the penicillins and
cephalosporins, which specifically hinder the synthesis of
the murein of the cell wall by inhibition of a D-alanyl transpeptidase. Other antibiotics, such as cycloserin, bacitracin,
novobiocin, vancomycin, and ristocetin also interfere with
the murein synthesis, but in a different manner.
2. Antibiotics which influence the permeability of the cell
membrane and thus increase the exit and entry of ions and
important cell components. For example, the tyrocidins,
polymyxins, polyene antibiotics, alkali metal ionophores
such as valinomycin, and the nonactins etc. belong to this
group.
3. Antibiotics that inhibit the synthesis of important cell
components in the interior of the cell, e. g. azaserin and diazooxonorleucin, which interfere with purine biosynthesis ;
also belonging to this group are a series of purine antibiotics such as psicofuranin, angustmycin and cordycepin.
4. Antibiotics which inhibit the synthesis of DNA and RNA.
Rifamycins, streptovaricins, and tolypomycin specifically
inhibit the DNA-dependent RNA polymerases. A large
number of antibiotics react with the DNA template and
thus interfere with or inhibit activity of the RNA or DNA
polymerases, e. g. actinomycins, chromomycins, anthracyclin antibiotics such as rhodomycin, cinerubins, pyrromycins, mitomycins, and porfiromycin etc.
5. Antibiotics which inhibit protein biosynthesis. The interaction of mRNA and tRNA with the ribosomes and the
enzymes taking part in protein biosynthesis can be disturbed and inhibited at various points by antibiotics. Several
antibiotics, some of which are currently being used in
therapy, interfere with these complicated processes, e. g.
tetracyclins, macrolides, chloramphenicol, and aminoglycosides such as streptomycin etc.
The lecture concluded with a report on some of the work
being carried out at Farbwerke Hoechst on the mode of
action of moenomycin and on the application of in uitro
systems of protein synthesis to specificity investigations of
tetracyclin derivatives and other antibiotics.-A knowledge of the effect of antibiotics on vitally important processes in the cell opens up new prospects for future cancer
and virus therapy.
Polarographic Trace Analysis of Inorganic
Substances in Non-Aqueous Solvents
(Example: Phosphorus and Silicon)
By Friedel Pottkamp and Fritz Umland (Lecturer)"]
Phosphorus and silicon can be selectively extracted as the
dodecamolybdato acids (abbreviated PMo and SiMo)
with butyl acetate"]. The acids are polarographically
active in the organic phase after addition of ethanolic LiCl
solution as supporting electrolyte. In the pprn range
(ca.
mol/l) two groups of three polarographic waves
are obtained which are best resolved by AC rapid polarography; position in volts versus the Ag/AgCl electrode in
1 N ethanolic Licl solution: 1. -0.14, 2. -0.46, 3. -0.65,
4. -1.29, 5. -1.50, 6. -1.85.
The AC peaks No. 1 and No. 2 correspond to the H + dependent waves also occurring in aqueous solution and
can be rendered by the following reduction process :
H,[PMo,,O,,]
+ n H e + nee
= H,[PMo,,O,,_,(OH)~]
where n = 2 and n = 4. The signals of the two isomeric forms
of dodecamolybdato-silicic acid appear at considerably
different positions: 1. a-SiMo: -0.13 V ; 2. P-SiMo:
- 0.30 V. The electrode process responsible for peak 3 is
not yet clear; however, it can be stated with certainty that
it is not due to reduction of an isopolymolybdic acid, which
accompanies the PMo signal in aqueous solution.
In the case of the more negative group of three peaks, a
diffusion controlled wave (peak No. 5 ) occurs at higher
LiCl concentrations (ca. 4 mol/l) which is flanked by two
adsorption controlled waves. These disappear with decreasing LiCl concentration and increasing H + concentration. With decreasing LiCl concentration, the wave No. 5
converts to a kinetically controlled limiting current. In the
case of PMo it is a matter of a catalytic H' reduction,
which permits an accurate determination of P in the ppb
range (3 o = 2 x 10- mol/l).
The catalytic H + discharge at a substantially more positive
potential than the discharge of stronger acids resembles the
H + discharge catalyzed by organic ammonium ions that
was reported by Nurnberg[21.
As distinguished from the ammonium depolarizers, however, the H f reduction catalyzed by PMo is dependent not
only on the K, value but also on other properties of the
acid. Thus, the catalytic wave is obtained with PMo acetic
acid but not with PMo + chloroacetic acid.
+
Consequently, a complex associate or solvate of (reduced)
PMo and acetic acid occurring as oxonium ion must be
assumed to act as depolarizer.
Lecture at Bonn on June 22, 1971 [VB 317 IE]
German version: Angew. Chem. 83,809 (1971)
Lecture at Tubingen on July 9, 1971 and at Karlsruhe on July 15, 1971
[VB 316 IE]
German version: Angew. Chem. 83,808 (1971)
I*] Dip1.-Chem. F. Pottkamp and Prof. Dr. F. Umland
[*I Prof. Dr. J. Schmidt-Thome
[I]F. U d ~ n and
d G. Wiinsch, Z. Anal. Chem. 225, 362 (1967).
[2] If. W Niirnberg and M. v. Starkelberg, J. Electroanat. Chem. 2,350
(1961); summary given therein.
Farbwerke Hoechst AG
623 FrankfurtiMain 80 (Germany)
Angew. Chem. internal. Edil. J Vol. 10 (1971) No. 11
Anorganisch-chemisches Instirut der Universitat
44 Munster, Gievenbecker Weg 9 (Germany)
817
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