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Book Review Protective Groups in Organic Synthesis. 2nd Edition. Edited by T. W. Greene and P. G. M. Wuts

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written, readable, up-to-date (covering the literature up to
1989), and contains few errors. Above all it identifies features of regulatory mechanisms that are common to widely
different fields of molecular biology. This is a useful text for
readers with a broad area of interest, written by a competent
author with a good overview of the subject; it offers an ideal
basis for a course or seminar on regulatory mechanisms.
Ferdinand ffucho
Institut fur Biochemie
Freie Universitat Berlin (FRG)
Iron Oxides in the Laboratory. Preparation and Characterization. By U . Schwertmann and R. M . Cornell. VCH Verlagsgesellschaft, Weinheim/VCH Publishers, New York, 1991.
XIV, 137 pp., hardcover DM 118.00.-ISBN 3-52726991-6/0-89573-858-9
Even on first thumbing through this little book, which has
a substantial binding and is pleasing to handle, one is impressed by the clear arrangement of its contents. Anyone
who has at some time struggled with the study of iron aquoxides will, after reading it for a short time, join this reviewer
in exclaiming “If only this had been available then!”.
Schwertmann and Cornell save the beginner from having to
do a lot of tedious literature searching, and they give much
valuable advice regarding the “perversity” of the chemistry
that can help to prevent failures.
The first few chapters explain the structural relationships
between the oxides and hydroxides of iron, and describe the
preparative techniques, methods of investigation, and special synthetic methods. These are followed by nine chapters
on the various compounds; five of these deal with iron hydroxides, three with iron oxides, and one with basic iron
salts, including also doped variants of these in some cases.
Very detailed methods are given for unambiguously
preparing each of nine important iron compounds, analyzing them, and storing them for use as reference materials;
these are goethite, lepidocrocite, feroxyhyte, ferrihydrite,
akaganeite, hematite, magnetite, maghemite, and iron(II1)oxyhydroxy sulfate. In future this will be the standard work
always referred to in connection with iron oxides and hydroxides.
According to an old saying, even the most excellent of
carpets must have its small defects, so as not to incur the
wrath of Allah. Here they include the missing literature citations on pages 29 to 33, and the absence of a cross-reference
to the oxalate extraction test for characterizing goethite
(page 46). In describing hydrolysis reactions (e.g., on
page 57) it would have been desirable to give the formula of
the hydrated starting species, and to mention the oligomeric
intermediate products. In describing the preparation of
goethite a consistent procedure should have been given: on
page 64 the caustic solution is added to the solution of the
metal salt, whereas a little later (p. 72) the metal salt solution
is added to the caustic solution. This fails to take account of
the fact that the isoelectric point of the primary precipitate
suspension is approached from the acidic side in one case
and from the basic side in the other. The nature of the impurities that become incorporated into the primary precipitate,
and can affect the properties of the end-product, is quite
different in the two cases.
To this reviewer the title of the monograph is a small
source of annoyance, which cannot be blamed on the authors. A more suitable title would contain the generic term
“iron aquoxides” introduced by Glemser (Angew. Chem.
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1961, 73, 785), although this has, unfortunately, not been
generally adopted. Perhaps this different way of looking at
things might stimulate an increased interest in the catalytic,
magnetic, electronic, electrochemical, and photovoltaic
properties of iron aquoxides (including the “iron oxides”
extracted from aqueous systems), which are very sensitive to
the presence of hydroxide groups, even in sub-trace concentrations.
The list of groups to whom the book is likely to be of
interest might well be extended to include the authors of
future monographs!
Dieter H . BuJ
Institut fur Anorganische Chemie
der Universitat Gottingen (FRG)
Protective Groups in Organic Synthesis. 2nd Edition. Edited
by 7: W Greene and P. G. M . Wuts. Wiley, Chichester,
1991. XVI, 473 pp., hardcover E 47.50.-ISBN 0-47162301-6
Ten years after the publication of the first edition of this
very successful book, Theodora W. Green and Peter G. M.
Wuts have now prepared a second edition taking into account the latest state of knowledge on the use of protective
groups. The division of subject matter is the same as in the
first edition. The book starts by describing the functions that
protective groups are intended to achieve. The protective
groups used for different compound types or groups are then
dealt with in turn: those for hydroxy groups, including 1,2and 1,3-diols, in Chapter 2, for phenols and catechols in
Chapter 3, for carbonyl compounds in Chapter 4,for carboxy groups in Chapter 5, for thiol groups in Chapter 6, and
for amino groups in Chapter 7. Lastly, Chapter 8 compares
the labilities and stabilities of commonly used protective
groups under different conditions (basic, acidic, oxidative,
etc.), summarizing these in “reactivity charts”; the charts are
identical to those in the first edition.
The material in the new edition is impressively up-to-date.
The literature has been comprehensively covered up to 1988,
with partial coverage up to 1990 for work published in
American journals and in Tetrahedron Letters. For each
protective group described, methods for its introduction and
subsequent detachment are indicated, though often only by
giving the reagents together with a literature reference. Generalized reaction equations are given in a few instances, but
more usually only the equation for a special case. In this way
the authors have achieved a high density of information. The
form of presentation adopted inevitably means that the special properties of protective groups, even of some very important ones, are treated too briefly, or sometimes even not
at all. This applies, for example, to the stereospecific neighbor group effects of acetates in the synthesis of glycosides.
Also there is no mention of the Koenigs-Knorr and related
syntheses. However, this was no doubt deliberate on the part
of the authors, since it is unmistakably evident that their
main area of interest and experience is in the synthesis of the
many natural products containing hydroxy and carbonyl
groups, which is also reflected in the relative emphasis given
to the various protective groups discussed. Consequently, it
is essential that the reader interested in using a particular
protective group in experimental work should consult the
original literature that is cited. A further reason for this is
that the authors have deliberately prefered to cite more recent examples of applications, and on grounds of economy
they have made the proviso that the citations do not neces-
0570-0833/92/0505-0658$ 3.SO+ .2S/O
Angew,. Chem. Int. Ed. Engl. 31 (1992) No. 5
sarily include the original publication in which the use of a
particular protective group was first proposed.
Despite these reservations, the book can be recommended
as an excellent and very useful source of information for all
chemists concerned with the synthesis of polyfunctional
compounds. Its coverage has been extended from that of the
first edition to include N-protecting groups for five-membered heterocycles and amides, but the latest developments
in the use of protective groups that can be removed enzymically were, of course, too recent to be included (H. Waldmann, Kontakte (Merck) 1991 (3), 33). The second edition
of “Protective Groups in Organic Synthesis” should be
available at all times in every organic preparative laboratory.
Hovst Kunz
Institut fur Organische Chemie
der Universitat Mainz (FRG)
Elementary Introduction to Spatial and Temporal Fractals.
(Series: Lecture Notes in Chemistry, Vol. 55.) By L. T
Fan, D. Neogi and M . Yashima. Springer, Berlin, 1991. IX,
168 pp., paperback DM 44.00.--ISBN 3-540-54212-4
The importance of fractals for describing complex structures and complicated phenomena is now generally recognized, and in the last few years quite a number of books
explaining the basic concepts of fractals in an easily understandable way have appeared. The book reviewed here is
such a one; it gives an introduction to spatial and temporal
fractals, and is intended particularly for students and research scientists working in the area of chemistry. The main
emphasis is on definitions, methods and applications; detailed mathematical derivations are kept to a minimum. It is
roughly 150 pages in length, and is clearly divided into four
parts followed by a detailed appendix.
In the first part the concepts and definitions of fractals are
explained. Topological and Hausdorff-Besicovitch fractals
and Euclidean dimensions are compared. Line, surface, and
volume fractals are also explained.
The second part contains examples that the reader can
easily understand using the knowledge gained from the first
part. The reader progresses via Cantor sets and Koch curves
to coastal perimeters. Particular attention is devoted to
methods for determining the fractal dimensions of irregular
surfaces. The concept of multifractals is also touched on
briefly, and it is shown that complex objects cannot always
be fully characterized by a single exponent; instead this may
require a distribution of exponents. The justification for this
procedure in terms of information theory is not gone into
here. Almost every book on fractals has to include a discussion of growth models; here the authors confine their attention to the best known of these, namely the Eden model and
the diffusion-generated aggregation model. Transport and
dynamic processes in fractal structures are not treated, and
accordingly only those characteristic exponents that are of
importance for structural analysis are discussed.
The third part of the book deals with temporal fractals.
These are also taken to include time series arising from measurements as a function of time, for example, data on the
prices of commodities as these vary with time. Such price
variations often do not show a normal (Gaussian) distribution. Fluctuations of this sort can be analyzed in terms of
stable distributions and fractional Brownian motions. Here
a distinction is also made between the properties of selfaffinity and self-similarity. The Hurst method for determining the characteristic exponents of discrete time series is deAngew. Chem. Inr. Ed. Engl. 3i (1992) No. S
0 VCH Verlagsgesellschaft mbH,
scribed. Only in the final section of this part do the authors
deal with “real” time fractals. These include stochastic processes in which the intervals between successive events have
a distribution characterized by a divergent average interval.
However, the fundamental importance of temporal fractals
for the interpretation of dispersive transport processes and
slow relaxation phenomena is scarcely mentioned.
The last part is devoted to chaos phenomena. The authors
clearly explain the role of the strange attractor in characterizing chaos in deterministic nonlinear systems, and that of
the Liapunov exponents in predicting trajectories. The relationship between fractals and chaos is made clear by a consideration of the fractal dimensions of the strange attractor.
The appendix should prove useful for readers interested in
practical applications. Here the fractal properties for three
particular cases are examined, by determining the fractal
dimensions for the perimeter of coal particles, for the surface
of rice hulls, and for the pressure fluctuations in multiphase
flow systems. Each case study begins with a theoretical introduction, which is followed by a description of the experimental arrangement, and finally a discussion of the results with
the help of figures and tables.
This book serves very well the needs of the reader who has
no previous knowledge of the subject, and wishes to acquire
the necessary background for an understanding of fractals,
especially for applications to chemistry, in a way that does
not make exacting demands. The price of DM 44.00 is appropriate for a book at this level.
Gerd Zumofen
Laboratorium fur Physikalische Chemie
der Eidgenossischen Technischen Hochschule,
Zurich (Switzerland)
Molecular Mechanism for Sensory Signals. By E. M . Kosower. Princeton University Press, Princeton NJ (USA),
1991. XVI, 438 pp., hardcover $79.50.-ISBN 0-69108553-6
The elucidation of the molecular mechanisms of sensory
perception, signal transduction, and the processing and storage of the information thus obtained is one of the most
fascinating research areas of modern biology and biochemistry. Many different approaches are being followed, involving a very wide variety of disciplines ranging from molecular
biology to neurobiology, and from molecular structure determination to the study of neuronal networks. E. M. Kosower has performed a valuable service in bringing together
in a single publication a survey of the current knowledge on
this complex subject.
At the beginning of the book the author defines a hierarchical classification of the world of living organisms, which
is made up of levels of organization of varying complexity.
A consideration of how these individual levels fit together
provides explanations for many apparently unconnected results. This approach from the viewpoint of systems and functions is becoming increasingly important in modern biology.
It is a concept to which E. M. Kosower frequently refers
back in this book, thereby making many of the relationships
easier to understand.
It is only very recently that detailed knowledge has been
gained about the mechanism of vision, the olfactory system,
the sense of taste, and the transduction of signals. From this
a number of common principles and levels of function have
been recognized; the receptors, which belong to the lowest
level, appear to have similar structures (containing seven
W-6940 Weinheim. 1992
0570-0833/92/0S05-0659$3.50+ .Dl0
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