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Collagen.

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erate increase in hydrogen pressure to 30 atms. shortened
the hydrogenation time considerably and reduced the catalyst requirement by 30 to 50%. The results obtained in
laboratory experiments were confirmed on a factory scale.
By using pure hydrogen, still further advances in the hydrogenation of commercial oils and fatty acids may be expected.
Owing to its high carotene content, palm oil requires more
intensive d e c o l o u r i s a t i o n than is necessary for other oils
and fats. The bleachability of the raw oil is chiefly influenced
by its free fatty acid content, preoxidation, and heavy metal
contamination. The above factors can be favourably influenced by suitable control over the harvesting, recovery, storage,
Reactions with Pyrylium Salts
C6HS
I
Soluble tropocollagen has been reported to be converted into
acid and alkali insoluble collagen via a procollagen step [I].
This process is thougt to involve a nonenzymatic curing process (aggregation, chemical crosslinking) which goes on
throughout life, at later stages assuming the form of ageing.
In an investigation of this process F. Verzar (Basel) and the
author studied the different forms of collagen and the products formed in the course of its thermal contraction [2]. As
experimental material, tail tendons from rats of different ages
were used. Results: 1. Tropocollagen from 3 months old rats
contains significantly more lipophilic amino acids and less of
the amino acids characteristic of collagen than either procollagen or collagen does M, 2 During thermal shrinkage (64 "C
in water), tendons from young (7 months) and old (30 months)
animals break down into water-soluble gelatin of high molecular weight and an elastic thread; the older the animal&,
the slower the rate of degradation. However, the proportiqn
of the products of decomposition remains roughly constant
(5- 10% insoluble product in the form of the elastic thread). 3. Surprisingly, the amino acid composition of the insoluble
material, whose hydrolysis products contain increasing
amounts of amino sugars as the age of the experimental
animals increases, is similar to that of tropocollagen, particularly of its a~ component [4].
Conclusion: Collagen is not merely cross-linked tropocollagen. In the course of its development, either a chemical
transformation of the tropocollagen peptide chain or a
linking of the tropocollagen onto a second independent
collagen intermediate (pro-collagen?) must occur. The results
show how essential it is to consider the solid state of collagen in chemical investigations of this material.
[GDCh-Ortsve-band Frankfurt1Main (Germany),
May 24th, 19621.
[VB 594139 IE]
V
Isomeric 2H- and 4H-heterocyclics were also isolated in the
thiopyran series. In contrast, pyridinium salts yield with
benzylmagnesium chloride only N-Alkyl-l,4-dihydropyridine
derivatives corresponding to the 4 H-compounds, as shown
unequivocally by comparison of their absorption spectra;
these cannot be rearranged into 1,Zdihydropyridine derivatives.
A report will be published elsewhere on reactions of pyrylium
salts with methylenetriphenyl-phosphorane,which, after
addition at C-2 (or C-6), produce benzene derivatives and
which yield 1,3,4,6,8-pentaphenyl-5-benzoylazulenein an
interesting sequence of changes [4].
[Chemische Gesellschaft Karlsruhe (Germany),
May 24th, 19621
[VB 597136 IE]
[l] K. Dimroth, Angew. Chem. 72, 331 (1960).
[2] K. Dimroth and K . H . Wolf, Angew. Chem. 72,778 (1 960).
[3] H. Kroke, Ph. D. Thesis, Marburg/Lahn 1962.
[4] K. H . Wolfand K . Dimruth, unlwblished results.
462
[VB 590137 IE]
M. Brenner, Basel (Switzerland)
Pyrylium salts are oxonium-carbonium salts which are
stabilised by mesomerism as aromatic 6x cations and which
add on nucleophilic reagents at C-2, '2-6, or C-4 [I]. The site
at which primary addition occurs appears to depend on the
type of reaction involved. Detailed examination of the reaction of 2,4,6 substituted pyrylium salts with benzylmagnesium chloride showed that, in this case, primary addition
takes place at (2-4.
2,4,6-Triphenylpyrylium perchlorate (I) yields the 4H-pyran
derivative 11, which, on treatment with perchloric acid, is converted with loss of acetophenone into 1,3 diphenylnaphthalene (111) in 90 % yield [2]. Under the influence of bases, such
as CaO or preferably disodium oxydiethoxide, I1 undergoes
an ally1 rearrangement to give the 2H-pyran derivative (IV),
which under the reaction conditions is converted immediately
into 1,2,3,5-tetraphenylbenzene(V). It is possible to isolate
IV on irradiating I1 with ultraviolet light [3]. Although IV is
converted into the benzene derivative V by bases, it does not
form a naphthalene derivative 111under the influence of perchloric acid. Thus the reverse rearrangement of IV inlo 11 by
acids does not occur.
IV
Treatment of 3-pentachlorphenoxy-l,2-epoxypropanewith
adipic acid produces 3-pentachlorphenoxy-2-hydroxypropyl
mono-adipate, which possesses antibacterial and antimycotic activity and hence may be used as an additive for
dressings and bacteria- and fungus-resistant coatings.
Collagen
K. Dirnroth. MarburgILahn (Germany)
C6Hs
I
and transport of the raw oil. These investigations have
already found practical application in the Congo, where socalled 'SPB Palm Oil' is now produced, which is characterised
by first-class bleachability and, as a result, reasonably good
stability of the finished product.
[l] See, for example, E. Budecke, Angew. Chem. 72, 663 (1960).
[2] A. Meyer, Ph. D. Thesis, Universitiit Basel 1962.
[3] Compare: D.S. Jackson et al., Biochim. biophysica Acta 27,
418 (1958).
[4] K. A. Piez et al., Biochem. Biophys. Acta 53, 596 (1961).
Anisotropy of Electronic and Physical
Properties of Graphite and its Crystal Compounds
A . R . Ubbelohde, London (England)
Large single crystals of graphite for investigations of anisotropy were obtained from metallic melts, but were never quite
pure. A more suitable product was obtained by pyrolysis of
CH4 or C3Hs at 1600-2300 OC; this graphite was deposited in
the form of plates about 1 mm thick having the carbon layers
orientated parallel to the supporting surface of polycrystalline
graphite, i.e. the c-axes lie perpendicular to the support, LatAngew. Chem. internat. Edit. / Vol. I (1962) I No.8
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