close

Вход

Забыли?

вход по аккаунту

?

Book Review The World of Physical Chemistry. By K. J. Laidler

код для вставкиСкачать
BOOKS
storage, manipulation. and retrieval of
structural information in computerized
systems. The Cheniicul Abstructs database
alone comprises more than ten million
such structures. The widespread and continuing use of the two-dimensional formula is, of course, a legacy of the past-it was
bequeathed to us by pioneers such as
Kekule and Crum Brown who developed
these formulas in the 1860s and then went
on to show how they could be applied in
the rationalization of chemical phenomena. Although this representation has
served us well. the question now being
raised is whether it has outlived its usefulness. Two-dimensional formulas are really
quite unsuitable for computerized storage
systems as the formulas need to be redrawn in the same format and orientation
before structures can be compared. The
comparing of structures and assessment
of similarities has become very important
during the past decade, following on from
the realization that molecular similarity
studies can be profitably exploited in the
early stages of molecular design. The design of pharmaceutical drugs and agrochemicals in particular has benefited. In
addition, a host of other modern chemical
problems involve investigation of the stereochemistry or chirality of molecular
species. It is thus hardly surprising that
chemists are now beginning to take a serious look at the representation of chemical
species by three-dimensional formulas.
The book reviewed here may be regarded as an important and innovative step in
this direction. It comes from the information studies group at the University of
Sheffield, arguably the world’s leading
group in the development of new approaches to the management of three-dimensional structural data. The author has
chosen to focus on the techniques that
may be used for searching three-dimensional structural databases, with special
emphasis on similarity searching. After
pointing out the limitations of two-dimensional searching, the author analyzes the
role and effectiveness of four different
three-dimensional similarity methods,
namely the distance distribution method,
the use of individual distances, atom mapping, and the maximal common substructure method. It is concluded that in overall terms the best of these is the atom
mapping method, an approach based on a
localized description of the three-dimensional environment of each atom in a molecule. When two molecules are to be compared, atoms with similar local environments are mapped on to each other. and
the similarities between atoms so mapped
are combined together to yield a global
measure of the similarity of the two mole360
(‘
cules. The rest of the book. including a
30-page appendix giving the results of
sample calculations, is devoted to a discussion of the atom mapping method.
Among other things, the author considers
how the method may be optimized and
made faster in practice, and describes a
variety of elaborations that broaden its
scope and applicability. In fact, with
appropriate modifications, the method is
applicable not only to relatively small
molecules but also to the largest of macromolecules.
In presenting all this material in one
volume the author has performed a very
useful service to many different kinds of
chemists. Structure-directed searching is
now the most common type of query
made to chemical structural databases
and the demand is likely to grow considerably in the future. This work not only addresses the increasingly pressing problem
of the storage and manipulation of threedimensional data but also shows how similarity notions may be successfully incorporated into the searching of such data.
Even though in its current form the
method cannot cope with very large databases, it is certainly able to handle medium-sized databases containing up to
50000 structures. Moreover. research at
present under way in several laboratories
around the world will undoubtedly push
up this limit substantially in the foreseeable future. The atom mapping method
has many exciting potential applications
and will feature in the design of molecular
species for a variety of applications. The
author is to be congratulated on bringing
out such a useful and succinct guide to this
rapidly evolving domain.
Dennis H . Rouvray
University of Georgia
Athens, G A (USA)
The World of Physical Chemistry. By
K . J. Laidler. Oxford University
Press, Oxford, 1993. 488 pp., hardcover E 55.00.-ISBN 0-19-855597-0
The title of this book should really have
been extended by adding the subtitle “A
Historical Discourse”. It contains a history of ideas in physical chemistry. from the
beginnings when this classification did not
yet exist, up to about the middle of the
present century. To make for lighter reading the author intersperses the account
with biographical notes about actors who
have played important roles on this stage,
although some of these have had little
recognition. Some additional short biographies are collected together in an ap-
VCH ~,rlf1g,\ge.\ellr~/7ufr
mhH, 0-694.71 Wiwhrim, lYY5
0.77O-U833;95;0303-03611B 10.00
pendix, and there are plenty of literature
references.
Three introductory chapters explain the
background to the development of physical chemistry within the overall framework of the sciences, and discuss the nature of the problems that it addresses and
the methods of working. The latter are
illustrated by taking as examples two
scientists with very different styles. H.
Eyring and R. Norrish, and by outlining
the development of the most important
centers of physical chemistry research in
England, Scotland, and North America.
One chapter is concerned with the sources
from which early physicochemical studies
originated, and describes the beginnings
of the journals that are now the leaders in
this field. The heart of the book consists of
the seven chapters outlining the development of the sub-disciplines of thermodynamics, the kinetic and statistical theory
of matter, chemical spectroscopy, electrochemistry, chemical kinetics, colloid and
interface chemistry, and quantum chemistry.
The author’s treatment is firmly linked
to the individual scientists and their contributions to the development of the subject. In the course of this he also mentions
some little known facts. For example, I
had not appreciated how wide-ranging
was the work of D. L. Chapman, who not
only contributed to the theory of the diffuse double layer by developing an early
forerunner of the Debye-Huckel theory of
electrolyte solutions, but also made important contributions to the understanding of reactions in the gas phase. Even
more surprising is the reappraisal of the
work of Agnes Pockel who, as a housewife
in Braunschweig, carried out studies in
her kitchen on the behavior of films of
organic substances, the results of which
were published thanks to the support of
Lord Rayleigh. In her experiments she
used an apparatus that already contained
the essential elements of the Langmuir
balance for measuring the surface tension
of a film.
The reader will find that many recent
developments are mentioned only very
briefly or are even completely absent.
However. to include all these would have
made a larger book than was intended.
The treatment is undoubtedly much colored by personal background, and an author from outside the English-speaking
world would have given a different emphasis in many respects. However, that in
itself adds to one’s interest in reading this
well-written book. In an age when the
principles of physical chemistry are nearly
always treated in a deductive way in textbooks. and the student is seldom told
+. 3 / 0
Angew. Chem. Int. Ed. Enyl. 1995, 34, N o . 3
BOOKS
about the historical development of the
subject. a book of this kind is especially
welcome. Without a knowledge of the historical background one’s understanding
of the nature and purposes of the discipline can only be superficial. Also the motivation for research gains an extra dimension when one is aware of the paths and
the false trails involved in arriving at the
present state of knowledge. The book
should be in the library of every physical
chemistry department, and is also highly
recommended for inclusion in scientists’
personal collections.
Heinz Gerischer
Fritz-Haber-Institut
der Max-Planck-Gesellschaft
Berlin (FRG)
Shikimic Acid. By E. Haslum.
Wiley, Chichester, 1993. 387 pp.,
hardcover,
E 75.00.-ISBN 0-47193999-4
Shikimic acid is the key to one of nature’s most astonishing and multifaceted pathways, namely the aromatic
metabolism developed in various organisms, mostly in
plants. but also in
microorganisms
and fungi. The fact
that the shikimate
pathway does not
exist (any longer) in
mammals is the reason for the worldwide intensive research, as it raises the possibility of
developing selective inhibitors for use as
herbicides, antifungalagents, o r antibacterial agents. One already successful example is the herbicide glyphosate, which
acts as an inhibitor of one of the enzymes
of the shikimate pathway (5-enoylpyruvylshikimate-3-phosphate synthase). The
above book by Haslam achieves considerably more than dealing with this important aspect of the application of biosynthetic studies and reviewing the progress
made in research on the shikimate biosynthetic pathway during the past twenty
years (since his first book. The Sliikinzate
Pat/iii.c/j..was published). The new results
of studies on the shikimate pathway offer
insights into intriguing questions of
molecular evolution, reveal a gold mine of
unusual enzymology. and include examples of important applications of the
latest advances in synthetic organic chemistry.
The book is divided into five chapters,
allowing the reader easy access to the different interesting facets of the shikimate
pathway. In Chapter 1 a short introduction and overview is given. This includes
interesting views on evolutionary aspects
(metabolic costs, multifunctional enzymes, possible reasons why the shikimate
pathway to aromatic compounds no
longer exists in mammals) and on the development of the methodologies (genetic
engineering, organic synthesis) used in
this research. Chapter 2 deals with the
chemistry (isolation, derivatization, and
synthesis) of the starting molecules and of
all intermediates of the common shikimate pathway, i.e. up to chorismic acid,
the major branch point. Several approaches to the synthesis of important intermediates such as the title compound
shikimic acid or chorismic acid are compared and evaluated. Chapter 3 provides
information about the unique enzymes
and the enzymology involved in the conimon shikimate pathway (up to chorismic
acid), reflecting the immense knowledge
gained in this field during the past twenty
years. A section within this chapter focuses on the above mentioned 5-enoylpyruvylshikimate-3-phosphate synthase and
its inhibitor glyphosate, the herbicidal
component of the commercially important weedkiller “Roundup”. The following two chapters are the longest and deal
with all aspects of the stages beyond chorismic acid, such as the various further
biosynthetic pathways, the products, the
enzymes involved, etc. Chapter 4 focuses
on generally occurring, so-called primary
metabolites and their enzymes, in particular the five key enzymes initiating the major metabolic branches from chorismic
acid (chorismate mutase, anthranilate
synthase. p-hydroxybenzoate synthase,
isochorismate synthase, and p-aminobenzoate synthase). The products thereby
formed (the “primary metabolites”) are
obviously essential for the producing organisms: the aromatic amino acids (e.g.
phenylalanine, tryptophan), the benzoand naphthoisoprene quinones (e.g.
ubiquinone. vitamin K), and the folate
coenzymes. Other enzymes that are involved, and the metabolism into and of
aromatic products, such as the lignin
metabolism in plants and the aromatic
amino acid metabolism in mammals, are
also discussed. Chapter 5 deals with the
so-called secondary metabolites, the more
or less individually produced “chemicals”
of a particular organism. The chapter begins with a brief discussion of the term
“secondary metabolism”, which although
historically based and often didactically
useful, is imprecisely defined and mislead-
ing. The treatment is subdivided into natural products from microorganisms and
those from plants. These special branches
occurring mostly in the late but sometimes
in the early shikimate pathway of certain
organisms lead to important natural
products such as antibiotics, mycotoxins,
alkaloids, and flavonoids. There is also an
addendum listing literature published after the manuscript was finished. This is
divided into the main areas of chemistry/
synthesis, enzymology. and biosynthesis,
and covers the most recent literature (up
to 1993!).
Shikimic Acid is written in an engaging
and easily understandable style. Occasional quotations (e.g. from the Bible,
from Oscar Wilde. and especially from
important early researchers in the field)
and excursions into the history of several
of the intermediates or products of the
shikimate pathway, together with the author’s remarkably wide grasp of the broad
field of natural products chemistry, make
it a pleasure to read. The different facets
of the rapidly advancing field of natural
products chemistry are presented so elegantly and absorbingly that it would be
small-minded to recount the few structural or printing errors. It is a pity that the
high price will prevent many students
from buying this excellent text, a rare example where a detailed overview of an important field of bioorganic chemistry is
successfully embedded in a very entertaining story. As a source of motivation and a
resource for preparing lectures as well as a
reference book. Shikimic Acid is a must
for everybody involved in teaching and
research in the broad field of natural
products and biochemistry.
Jiirgen Rohr
Institut fur Orpanische Chemie
der Universitat Gottingen (FRG)
Shape in Chemistry. An Introduction
to Molecular Shape and Topology. By
P. G. Mezey. VCH Publishers. New
York, 1993. XI, 2 2 4 p p . , hardcover
$75.00.-ISBN 0-89573-727-2
Shape is a concept of interest to a wide
range of scientists. For instance, biologists map the shapes of microorganisms,
geologists the shapes of rocks, and
chemists the shapes of molecules. However, all use different measures, for there is
no general agreement on how shape
should be defined. Most chemists resort to
the concept as and when it is needed, without ever trying to get to grips with it in any
deep abstract sense. In this respect shape
resembles a number of other chemical
Документ
Категория
Без категории
Просмотров
2
Размер файла
316 Кб
Теги
physical, chemistry, book, laidler, world, review
1/--страниц
Пожаловаться на содержимое документа