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Chemical Synthesis of Polypeptides and the Hydrodynamic Properties of Their Solutions.

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I Lb-band upon the IL,-band. The splitting of the acridine
band in the 9-substituted derivatives is to be explained by a
bathochromic shift of the ILb-band.
The preband, occurring at about 360 m p with the diacridanyls is markedly influenced by temperature and disappears
almost completely at -183 "C. This implies the existence of
two different conformations of diacridanyl, the conformer
richer in energy absorbing at the longer wave length (at 360
mp). I n the frozen state, the diacridanyls undergo a n interesting photolysis involving sp!itting of the 9,9'-bond and
electron detachment, acridinium cations being formed. On
melting the solution, diacridanyl is reformed.
Studies of the Tetrahydrate o f Hydrogen
Bromide H904 Br"
@
H . Zimmerrnnnn, d . Rudolph, and G . Henning,
Munchen (Germany)
At low temperatures, hydrogen bromide forms a crystalline
tetrahydrate, m.p. --56 "C [7]. Its infrared spectrum was
examined at - - 170 "C.In contrast to that of the corresponding
acid solutions at room tempcrature, it exhibits a fine structure
[8]. In particular, the long-wave infrared spectrum shows
groups of sharply defined bands, for which it was possible t o
set up a term series for the vibrational states. This term system
indicates that the substance IS present in the form H904+Rr .
The H 9 0 4 +complex consists of a pyramid-shaped H30+ ion
that is linkec! to three further water molecules by exceptionally strong hydrogen bonds. This complex has therefore ii
structure similar to that of the H904' ion, which is present
in aqueous solutions of acids, according to Wicke, Ei.yc,n.
and Ackernitrnn [9].
From the infrared spectra of the tetrahydrate of hydrogen
bromide, it appears probable that the proton in the hydrogen
bonds under discussion moves in an asymmetrical potential
field with two minima. At low temperatures, it is fixed i i i the
lower potential trough. Proton mobility therefore is very
low, and the conductivity at -180°C amounts to K < 10-9
mho. cm-1. The conductivity varies with temperature and
shows a sharp point of inflection at -90 ' C . A discontinuous
change in the properties of the substance at - 90 "C can be
similarly proved in the wide-band nuclear resonance spectrum, but not in the infrared spectrum.
[VB 780/136 IE]
German version: Angev. Chem. 76, 305 (1964)
[6] Cf., for example, V . Zanker and P . Sehntid/, 2. physik. Chem.
N F 17, I 1 (1958); A . Kellmann, J. Chim. physique 57, 1 (1960);
M . Giurgea, V . Topa, and S. Haragea, ibid. 58, 705 (1961).
171 S . U. Piekering, Phil. Mag. V, 35, 1 I 1 (1893).
3hemical Reactions with (n, y),
Tission Recoil Atoms
9-,and
F. Baumgartner, Munchen (Germany)
Recoil atoms resulting from nuclear reactions are capable of
forming new molecules. Nuclear reactions thus represent a
means for synthetizing molecules independently of preparative chemical methods. Thus, by P-disintegration of the
parent substances, it was possible to prepare the hitherto
unknown compounds dicyclopentadienylrhodium ( I ) , dienzene technetium(1) (2), and cyclopentadienyltricarbonylxhnetium (3). These substances were purified by sublima3n. (2) is a stable Tc cation, which has also been synthetized
macroscopic amounts.
.~
-
[81 Cf. Th. Ackermann, Z . physik. Chem. N.F. 27, 269 (1961).
191 E. Wicke, M . Eigen, and Th. Ackerniann, Z . physik. Chem.
N.F. I , 340 (1954).
Chemical Synthesis of Polypeptides and the
Hydrodynamic Properties of Their Solutions
G. Spach, Strasbourg (France)
Condensation of the tripeptide L-alanylglycylglycine with
dicyclohexylcarbodiimide or ethyl metaphosphate yields
only products with a degree of polymerization < 6. In order
to obtain high molecular-weight copolypeptides with the
amino acids in a regular order, a new synthesis depending on
internal anhydride formation was considered. In a preliminary
investigation, the carbamyl chloride ( I ) was synthetized by
the action of phosgene on glycyl-L-proline. The substituted
diketopiperazine (3) containing a n intramolecular peptide
link was formed from ( I ) with the stoichiometric quantity of
triethylamine. The intermediate anhydride (2) was not isolated and is probably of low stability [l].
r
T o extend the range of syntheses with recoil atoms, i.e. in
order to be independent of specific parent substances, we
used two-phase mixtures of uranium oxide and the target
material. In the uranium phase, energy-rich recoil atoms were
produced by nuclear fission and some of these, e.g. 105Ru,
1311, 99M0, react with the target compound. The following
radioactive molecules have been prepared via uranium fission :
U (n.0
U (n,f)
+ Fe(CsH5)z
+ Fe(CsHs)2
u hf)
+ Cr(C0)6
u ( K f ) + Cr(GH6)z
u (n,f) + CI(C6Ha)z
u (n,f) f C6H5-X
1
H,
4
p
H,C'
I
'YH2
N--f
Ru(CSHS)Z
+ csH~FeCsH41
--f
OC',
H,C-NH
C H\
1-71
C
, 0
MO(C0)6
-+ Mo(CsH6)z
-+ TC(C&)z+
+c~H5-1
X =.CI, Br, or I
According to the last equation, organically bound halogen
may be substituted very selectively by fission iodine. Between
500 and 4 ° K the yields of these recoil syntheses are independent of the temperature.
[Chemische Gesellschaft Heidelberg (Germany),
January 14th, 19641
[VB 790/131 1El
German version: Angew. Chem. 76, 307 (1964)
Atr,ycw. Chem. internat. Edit. / Vol. 3 (1964) ,! No. 5
Examination of dilute solutions of the homopolypeptides
polybenzyl-L-glutamate and polycarbobenzoxy-L-lysine in
dimethylformamide showed that the molecules exist in the
form of a helix of type 3.010, with three monomers per turn,
while in the solid state they assume an a-helix configuration
with 3.6 monomers per turn [2].
Polybenzyl-DL-glutamate exists in both the A and B forms
depending on the polymerization solvent. The A form appears
[ I ] A . Braek, These 3e cycle Universite de Strasbourg, 1963.
[2] G. Spaeh, L . F r e u d , M . Dnune, and H. Benoit, J. molecular
Biol. 7, 468 (1963).
389
to be a flexible chain of rod-like units of about 100 i( length
each; it is probably a block-copolymer i n which sequences
of I) and L residues altcrnatc. The rigid molecules of the B
form can be considered in a first-stage model as a mixture of
polybenzyl-1.- and -u-glutaniate.
[GDCh-Ortsverband Marburg/Lahn (Gcrniany)
January 24th, 19641
[VB 797/137 IE]
The acyloxyphthalides (2) are hydrolysed under mild
conditions to the free hydroxyphthalides (3). More vigorous
attack opens the lactone ring, producing I-hydroxynaphthalene-3-carboxylic acids ( 4 ) and aldehydes R CHO [3].
V"
I,!
I<
I
German version: Angew. Chem. 76, 381 (1964)
A New Synthesis of Hydroxyphthalides
A . Sieglirz, Miinchen (Germany)
I-Oxotetralin-3-carboxylicacids ( I ) react with carboxylic
anhydrides to yield acyloxyphthalides (2).
f1)
(2)
The reaction was carried out with numerous derivatives of
( I ) , including 3-0x0- 1,2,3, 1Ob-tetrahydrofluoranthene-lcarboxylic acid [ I ] and 1-0~0-4,5-rnethylene-1,2,3,4-letrahydrophenanthrene-3-carboxylic acid [2], and gives positive
results with numerous anhydrides of aliphatic, aromatic,
al kylaromatic, and heterocyclic carboxylic acids.
[ I ] A . Sieglit;, H.TrOster, and P. Bdime, Chem. Ber. 95, 3013
(I962).
[2] .4. Sieglif; and M.: Scliidlu, Chem. Ber. 96, 1098 (1963).
(3)
Hydroxyphthalides with a free 4-position (3), R2-H,
couple with diazonium compounds in this position. Those
with a substituted 4-position ( R ~ = C H ~ , C ~ H
and
S ) hydroxyphthalides derived from 3-0x0- 1,2,3,1Ob-tetrahydrofluoranthene-1-carboxylic acid undergo coupling in the 2-position,
1-51
with simultaneous elimination of the aldehyde RCHO. The
azo dyes (5) thus obtained (also accessible from (4) when
the 4-position is substituted) are readily dehydrated to form
o-quinonoid indazolone dyes ( 6 ) .
[GDCh-Ortsverband Berlin (Germany),
February loth, 19641
[VB 796/135 I€-
German version: Angew. Chem. 76, 384 (1964)
[3] H . Schmid, Th. M . Meijer, and .A. Ebnotlier, Helv. chim.
Acta 33, 595 ( I 950).
SELECTED ABSTRACTS
The role of formylpyruvic acid in forming the dyestuff of the
Warren reaction has been clarified by R. Kuhn and R . Lutz.
The Warren reaction is used for colorimetric determination
of free sialic acids. Formylpyruvic acid was thought to occur
as an intermediate in this reaction, but neither it nor the
dyestuff were known in the free state.
Kuhn and Luiz synthetized ethyl ethoxymethylenepyruvate
(2), b.p. 135-138*C/11 mm, in 23 % yield from ethyl
pyruvate and triethyl orthoformate. Claisen saponification
of (2) gave red-brown flakes of the sodium salt of formylpyruvic acid; when an aqueous solution of this salt was
heated with 2-thiobarbituric acid, it became deep red.
Tiny blue crystals separated out of the red solution
(45 yield). This blue dyestuff ( I ) has the same absorption
spectrum as the dyestuff of the Warren reaction (Amax =
550 my, smax= 1 . 3 4 ~
105 in cyclohexanone). / Biochem. Z .
338, 554 (1964) / -De.
[Rd 838/219 I€]
important. cis-Isomers are generally more labile than the
rmns-isomers, and partial isomerizalion always occurs
However, even the geometrically isomeric nitro complexes
which are very poorly separable by fractional crystallizatio
owing to the close similarity of their physical and chemic
properties, can be satisfactorily separated by thin-la)
chromatography. The mobile phase suitable for this separa
tion is a n ammonium acetate buffer in a mixture of methanol
and ethanol. / Helv. chim. Acta 46, 2636 (1963) / -KO.
[Rd 848/233 IE]
Caprolactam hydroperoxide, the first representative of a new
type of peroxide, was prepared by A . Rieche and W. SchBn.
A caprolactam melt takes up oxygen at 75°C to give the
hydroperoxide ( I ) in very low yield. Pure, crystalline ( I )
melts at 139'C with vigorous frothing. Co(I1) and Fe(I1)
salts catalyse the conversion of ( I ) into adipimide (2) which
is also obtained on oxidation of caprolactam at 100°C. On
<:
Separation of the geometric isomers of cobalt complexes has
been achieved by H . Seiler, C. Biebricher., and H. Erlenmeyer
using thin-layer chromatography, For complexes of the type
[Co enzC121X (X = CI, NO3, or CNS; en = ethylene diamine),
a suitable mobile phase is a chloride-free, methanolic acetate
buffer. The fmns-complex always migrates further than the
cis-complex, independently of their solubilities; apparently
the polarity and water content of the mobile phase are very
390
/
(2)
l
131
hydrogenation, ( I ) forms w-formylpentanoamide ( 3 ) . Caprolactam hydroperoxide disturbs the polymerization of caprolactam in the same manner as air. / 2. Chem. 3, 451 (1963) /
-Kr.
[Rd 842/220 IE]
Angew. Chem. internat. Edit. J Vol. 3 (1964)
/ No. 5
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