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Book Review Vitamin-Bestimmungen. Erprobte Methoden (Determination of Vitamins. Approved Methods). By R. Strohecker and H. M. Henning

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The properties of alkylstannosiloxanes, alkylsiloxanes and
alkylstannoxanes were compared by H. Schmidbaur and H .
Hussek. They prepared, for example, hexamethylstannosilyield acoxane (m.p. -59”C, b.p. 141 OC/720 mm) in 78
cording to the reaction
(CH&SiOLi
+ CISn(CHp)3 + LiCl + (CH&Si-O--Sn(CHa)s
The simplest distannosiloxane (b.p. 77 ‘C/l mm) is formed in
86 % yield according to the reaction
2 (CH3)aSnOLi iClzSi(CHs)2 + 2 LiCl
+ [(CH3)3Sn0]2Si(CH&
The analogous stannodisiloxane was also prepared.
The alkylstannosiloxanes are colorless, highly toxic compounds mostly with an unpleasant odour. They are thermally
not so stable as the alkylsiloxanes and -stannoxanes. The
majority of the compounds decompose above 150°C into
siloxanes and stannoxanes. The alkylstannosiloxanes exist
in monomeric form; they are very reactive towards electrophilic and nucleophilic agents. In this respect they resemble
the (even more reactive) alkylstannoxanes. The N M R spectra
show the gradual change of the bond properties in siloxanes,
stannosiloxanes and stannoxanes. / J. organometallic Chem.
I , 244 (1964) / -Kr.
[Rd 896/254 IE]
BOOK REVIEWS
Vitamin-Bestimmungen. Erprobte Methoden (Determination
of Vitamins. Approved Methods). By R . Strohecker and
H. M. Henning. Published for E. Merck AG., Darmstadt by
Verlag Chemie, GmbH., Weinheim/Bergstr. 1963. 1st
edit., 365 pp.. 42 illustr., 8 color plates, linen, D M 42.(about S 10.50) [*I.
This comprehensive, excellently produced and illustrated book
by two experienced analysts provides a collection of reliable
methods for estimating the 15 most important vitamins, applicable primarily to pharmaceuticals and concentrates, but
also to foods and animal feedstuffs. Almost all the currently
known chemical, physico-chemical, and microbiological
methods of liberation, extraction, separation, and assay are
used and described in a readily intelligible manner. The
relevant literature could not be completely reviewed, but on
the other hand, the reader is familiarized with valuable
analytical information as yet unpublished elsewhere, e.g. the
extensive use of thin-layer chromatographic procedures, which
also provide simple tests for the specificity of the reactions.
The authors very correctly emphasize that there are n o generally applicable analytical methods. The appropriate combination of procedures for extraction, purification, and determination must be selected critically and adapted to the specific
properties and composition of each individual sample, even
in the case of relatively simple pharmaceutical preparations.
In this regard, thorough study of the introductory chapter,
which provides a wealth of basic information and guidance,
is indispensible.
The proposed methods have proved their reliability in the
reviewer’s laboratory, where the details of the methods were
sometimes altered in a few points. For colorimetric measurements, we generally use a reagent blank rather than a n empty
cuvette. The vitamin D determination by direct spectrophotometry or colorimetric measurement gives correct values only
with pure crystalline vitamin D, and gives high results for all
other forms of the vitamin owing to interfering impurities.
It is also useful to dissolve materials for separation by thinlayer chromatography either in the mobile phase o r in one of
its components in order not to influence the separation by the
presence of a n extra solvent. Although it is stated that
relatively large errors are inherent in several methods, more
details would occasionally be desirable.
This valuable book is recommended to all engaged in the
analysis of vitamins.
B. Schmidli
[ N B 181/75 IE]
Kurzes Lehrbuch der Biochernie fur Mediziner und Naturwissenschaftler (Concise Textbook of Biochemistry for
Medical and Science Students). By P . Kurlson. Georg
Thieme Verlag, Stuttgart 1962. 3rd edit., XVI, 360 pp.,
63 illustrations, linen D M 31.- (about $ 8.00).
In recent years it has become clear that a modern introduction
to biochemistry is necessary, not only for medical students,
but for all scientists. Karlson’s book, now appearing in its
third edition, fulfils this need.
~-
[*I
An English edition will appear by the end of 1964.
Angew. Chem. internat. Edit.
Vol. 3 (1964) 1 No.7
The arrangement of the first edition is unchanged except for
a new chapter, twelve pages long, in which mineral metabolism, physico-chemical aspects of water as a solvent, osmosis
and active transport, are discussed.
It seems desirable, even in a book for beginners, to consider
basic physico-chemical concepts, such as equilibria, in an
introductory chapter. There should be also fuller discussion
about the fundamentals of macromolecular chemistry, so
that problems of molecular biology can be understood in the
further course of studies. The reviewer has observed again
and again that even those students, whose grasp of the subject is not very great, approach the physico-chemical fundamentals of biochemistry with enthusiasm.
The manner in which the author has mastered the wealth of
material, so that the most recent developments are discussed
without noticeable omission, fascinates the reader throughout
the book. Naturally, the reader’s knowledge of organic chemistry is assumed.
Mistakes or misprints have been almost eliminated in this edition.Atrivia1 mistake: diesterase cleaves theO-P bond(p. 121).
The book will keep its important place in biochemical teaching.
F. Cramer
[NB 180/78 IE]
Altamira und die Urgeschichte der chemischen Technologie.
(Altamira and the Prehistory of Chemical Technology). By
E. Pietsch. German Museum -Transactions and Reports Volume 31, No. 1. R. Oldenbourg Verlag, Munich, 1963.
1st Edit., 68 pp., 35 illustr., 12 color plates, 1 chronological
table, brochure D M 4.80 (about $ 1.25).
This brochure reports a veritable masterpiece accomplished
for the German Museum by the author and his assistants.
It consisted of a reproduction, faithful almost even to the
very materials used, of a section 9.5 m by 4.6 m from the
ceiling in the “Cave of Bulls” at altamira in Spain. This
portion shows a typical selection of the masterly animal
portraits created by our ancestors in the period from the
Aurignacian to the Magdalenian culture phases 30000 to
10000 years ago, in younger Palaeolithic times. Since the roof
of the cave, for obvious reasons, could not be touched, it had
to be photographed by stereophotography for mensuration.
The resulting plan served as basis for a plaster of Paris pattern
which was given a plasticine skin in order to reproduce the
fine structure in all details. From this pattern a mold was
made in silicone rubber which was itself supported in a bed
of plaster of Paris. The reproduction of the roof was finally
cast in this mold and, in order to reproduce the limestone in
the cave as faithfully as possible, a mixture of chalk from
Solnhofen and white cement (Dyckerhoff) was used. Only iron
oxide pigments and charcoal were used for painting, just as in
the original. The fixative for the paint had to be Mowilith [*I
instead of the natural calcium bicarbonate contained in the
moisture on the roof. Even the illumination in the exhibition
room has been arranged to approximate the tallow lamps of
the Palaeolithic period.
[*I Mowilith is the German trade name for synthetic drying oils
containing polymerized vinyl and acetylenic compounds.
523
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