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Book Review Biocatalysts in Organic Synthesis. (Series Studies in Organic Chemistry Vol. 46.) By J

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photodissociation processes and the occupancies of the different quantum states of
the dissociation products, which yield important information about the dynamics
of such photodissociation processes. The
author devotes special attention to dissociation processes in van der Waals molecules and vibrationally excited molecules.
and to nonadiabatic processes. Lastly
some recent experiments using ultrashort
(femtosecond) laser pulses are described.
To summarize, this is a substantial
work which is of a high standard throughout. It can be recommended unreservedly,
not only for theoretically orientated
chemists but also for experimentalists
working in the fields of photochemistry,
spectroscopy. or chemical kinetics, and
for advanced students who wish to become involved in this interesting area of
physical chemistry.
Peter Wiesen
Institut fur Physikalische Chemie
der Universitat-Gesamthochschule
Wuppertal (FRG)
Biocatalysts in Organic Synthesis.
(Series: Studies in Organic Chemistry, Vol. 46.) By J. Halgas. Elsevier,
Amsterdam, 1992. XIV, 334 pp.,
hardcover $ 180.00.-ISBN
0-44498698-7
Biocatalytic transformations have led
to important advances in asymmetric synthesis, and have now become an indispensable part of the armory of methods in
this field. Introductory surveys for nonspecialists are much in demand because
biological catalysts occur as a wide variety
of special types with unique characteristics and can be used in diverse ways, and
because the original publications are scattered throughout many journals of different disciplines. By the nature of the
book Halga’s this review may be seen to
some extent as a postscript to other recent
reviews of monographs published on this
theme in 1992 (L. Poppe. L. Novak, Selective Biocutulysis. VCH Verlagsgesellschaft. Weinheim, 1992; K . Faber, Biotrunsformutions in Organic Chemistry,
Springer, Berlin, 1992; reviews: Angew.
Chem. Int. Ed. Engl. 1993, 32, 920: H. L.
Holland, Org-unic Synthesis bvitii Oxidutive Enzyzes, VCH Verlagsgesellschaft,
Weinheim, 1992; review: Angew. Chrm.
Int. Ed. EngI. 1993, 32, 622).
The present book of nine chapters begins with three introductory discussions,
first about the fundamental nature of enzymic catalysts (Ch. 1 , 12 pp., nomenclature, effects of solvent, temperature, and
pH. inhibition). then about the forms in
which they are used (Ch. 2, 33 pp., microorganisms and isolated enzymes in
both free and immobilized forms), and
thirdly about the basic principles of enzymic stereoselectivity (Ch. 3. 12 pp.).
The main body of the book, on synthetic
applications, begins with Chapter 4
(“Substitution Reactions”, 22 pp.). Here
the author collects together a miscellany
of reactions using enzymes of widely different types (haloperoxidases, transferases, lyases) which can be formally classed
as substitutions (methylation, halogenation, transglycosidation; however, glycosyl transferases are not included, despite
the fact that an index entry leads one to
expect this). Chapter 5 deals with additions at C = C and C = O bonds (21 pp..
Michael addition, aldol addition, formation of cyanohydrins and acyloins).
Chapter 6 is the longest (97 pp.) in
. accordance with the preparative importance of
its subject. the various aspects of the conversion of esters by hydrolytic enzymes
(transesterification, hydrolysis, formation
of phosphate esters). Chapter 7 (20 pp.) is
devoted to the analogous reactions of
amides (including hydrolysis of nitriles) .
Finally, the last two chapters are focused
on the wide range of preparative biocatalytic redox processes. and the methods
needed to regenerate cofactors. Chapter 8
(28 pp.) describes the various types of enzymic oxidations of organic compounds
(alcohols, amines to carbonyls. BaeyerVilliger, hydroxylation. dehydrogenation,
oxidation at heteroatoms; also included
are preparative applications of galactose
oxidase, which I did not find in the pertinent monograph by Holland mentioned
above). Chapter 9 (65 pp.) concentrates
on reductions (mainly of C=O bonds. including reductive amination, but also reduction of C=C, NO,, and other groups).
At the end of the book is a detailed bibliography (939 references extending u p to
the end of 1989; interestingly. reference [9]
is to a monograph that has not yet been
published!). together with separate lists of
recommended further reading for each
chapter (important original publications
and recent review articles extending up to
1992, comprising altogether an additional
121 citations). Lastly there is a six-page
subject index.
It is already evident from the relative
importance given to the individual chapters that Halgas, in noticeable contrast to
the authors mentioned above, is especially
concerned here to present the full breadth
of available methods of enzymic catalysis
and the individual potential for synthetic
applications. On the one hand he devotes
an appropriately large amount of space to
the currently most important types of
reactions (transesterification/hydrolysis,
oxidation and reduction) and enzymes.
while on the other hand, by giving a
balanced broader survey of the variety of
biotransformations used in organic synthesis, he undoubtedly succeeds better in
providing readers with ideas for using enzymes to solve their own synthetic problems. Also very useful for be,‘Oinners are
the frequent cross-references to relevant
technological processes, e.g.. in the synthesis of amino acids.
The text is generously illustrated by formula schemes, although the formulas are
unnecessarily large. This often spoils the
continuity of flow schemes in relation to
page breaks, especially annoying if one
must turn the page to find the products of
a reaction (pp. 15116, 67/68. 199/200.243!
244, 2851286). Occasionally one wonders
why trivial items (e.g.. the depiction of
cx- and P-methyl glucoside to exemplify
glycosides) are presented at the same level
as more important matters.
The author’s concern for variety and
completeness. which is evident from the
evaluations of different procedures. and
from the wealth of experimental details
given, may occasionally cause the reader
to lose sight of the wider objective. Although some of the data are summarized
in the form of tables, still more use of this
form of presentation would definitely
have greatly increased the usefulness of
the book. Because little systematization
has been brought to the varied collection
of individual results and preparative details, many important facts will only become apparent after a more thorough
reading, rather than allowing a rapid
grasp of the salient points. Moreover. this
is not helped by the fact that the index is
too brief to do justice to the amount of
information in the book. Although the
reactions described can be well accessed
by the many cross-references to the enzymes used to catalyze them, and those to
the various microorganisms from which
they are derived, this will only be of
limited use as a searching aid to the synthetic chemist lacking relevant experience,
who is primarily interested not only in reaction types but in compounds, their
structural features, and specific conversions.
The book is largely free from typographical and factual errors: the few that
remain are of an obvious kind which serve
to entertain rather than cause problems.
and one is content to overlook them. (Examples: on p. 72 dichlorofumaric acid
supposedly splits off HF, and on p. 104 an
pe value of 98% is given for cyclopropanol.) On the other hand it was an-
noying, especially in a fairly expensive
book, to find that the review copy had
printing defects on several pages, where
multiple printing had produced shadow
characters making the text difficult to
read.
Although the material in this book by
Halgas is not especially up-to-date, its
particular strength lies in providing a
comprehensive and detailed account of
enzymic methods in organic synthesis.
Thus it is suitable both as an introduction
to preparative biocatalysis and as a permanent reference source for research
chemists and lecturers with interests in
this field.
WoljlDieter Fessner
Institut fur Organische Chemie
und Biochemie
der Universitit Freiburg (FRG)
Liquid Crystal Polymers. (Series :
Speciality Polymers. Series editor:
J. M . C. Con'ie.) Edited by N . A .
Plat&. Plenum, New York, 1993.
438 pp., hardcover $ 110.00.-ISBN
0-306-4421 9-1
This book consists of ten chapters in
which twelve Russian authors summarize
the rapid developments that have occurred in the field of liquid crystal polymers in the last 15 years or so. Especially
noteworthy is the very good coordination
that has been achieved between the various specialists with regard to content,
consistcnt use of symbols, and form of
presentation. Each chapter has a short introduction linking it to the other authors'
contributions and briefly describing the
historical development. On the whole the
editor has succeeded well in ensuring that
the individual authors' reviews of progress in liquid crystal polymers are highly
informative and critically presented. It is
entirelb appropriate that in this area of
research the Russian literature should be
given special emphasis, as much of it is not
sufficiently well known in other countries.
However, it must be noted less favorably
that there are only sporadic references to
work published from 1987 onwards. Brief
descriptions of the ten chapters follow.
Chapter 1 : Statistical physics of liquid
crystalline order in polymeric systems
(A. R. Khoklov, 38 pp.. 139 refs.). Theoretical models for both rigid and flexible
polymers are critically discussed with references to the original papers. Melting behavior and elastic and rheological properties are treated in rather more detail. This
chapter provides the fundamental basis
for the following chapters. Chapter 2:
Phase equilibria in polymer systems with
liquid crystalline phases (S. P. Papkov,
32 pp., 58 refs.). After a general classification of the types of phases and explanations of the meaning of thermotropic and
lyotropic phases. the author concentrates
mainly on the solution behavior of polymers with rigid chains. The predictions of
several different models are compared.
Chapter 3: Molecular structures of polymers with mesogenic groups (I. N. Shtennikova, 54 pp., 111 refs.). Different conformations are discussed, and the implications in relation to streaming birefringence and the Kerr effect are briefly considered. This is followed by a discussion of
these effects as observed in lyotropic polymers and in polymers with main and side
chains, from the standpoints of different
theories. Chapter 4: The mesomorphic
state of polymers with flexible chains
(Yu.K. Godovskii and V.S. Papkov,
38 pp., 93 refs.). Various experimental results on linear polyorganosiloxanes, polyphosphazenes, and cyclolinear polyorganosiloxanes are summarized and
evaluated. Chapter 5: Thermotropic liquid crystal polymers with mesogenic
groups in the main chain (S. S. Skorokhodov, 30 pp.. 82 refs.). Continuing
the theme of Chapter4, syntheses of
polyesters, polyethers, and polyurethanes
are described. Special attention is devoted
to the use of texture observations to recognize the liquid-crystalline state, and to
the detection of order. The effects of the
previous history of the polymer on its
physico-chemical properties are discussed. Chapter 6: Comb-like liquid crystal polymers (V. P. Shibaev, 57 pp.,
69 refs.). V. P. Shibaev, one of the 'fathers' of polymers with liquid-crystalline
side chains, discusses some of his areas of
research: methods for the synthesis of
polyacrylates. polymethacrylates, polyesters, and polypeptides with various liquid-crystalline side groups. Topics receiving special attention are the glass transitions of the polymers, and related
discussions regarding the thermal equilibrium, the effects of chemical variations
(including the degree of polymerization)
on phase transition temperatures, structural aspects of the phases. and ferroelectric polymers. The survey of nematic polymers and the comparison with smectic
polymers in this chapter are some of the
most valuable sections of the book. Unfortunately it has only been possible to
give a hint here of the start of the rapid
developments in the field of elastomers
that have occurred in the last few years.
Chapter 7: Liquid crystal polymers of the
cholesteric type (Ya. S. Freidzon and V. P.
Shibaev, 52 pp., 87 refs.). By limiting the
topic area to be covered, the authors have
been able to give a detailed and comprehensive treatment which is well worth
reading, even by specialists. Chapter 8:
Structural transformations of thermotropic liquid crystal polymers in electric
and magnetic fields (R. V. Talroze and
N. A. Plate, 36 pp., 67 refs.). Starting
from the fundamental principles, the authors deal mainly with electrooptical effects of dielectric and hydrodynamic origin, and with induced phase transformations and memory effects (information
storage). This section should be especially
useful to technologists with interests in
this area. Chapter 9: Rheological properties of liquid crystal polymers (B. G.
Kulichikhin, 44 pp., 119 refs.). The theoretical and experimental aspects of polymer solutions and melts are treated comprehensively. The author also briefly
discusses some hitherto unsolved experimental problems and potential technological applications. Chapter 10: Highstrength and high-modulus fibers from
liquid crystal polymers (A. V. Volokhina
and G. I. Kudryavtsev, 36 pp.. 94 refs.).
The authors discuss the technology and
characterization of Aramid fibers, ultrahigh-modulus fibers made from heterocyclic monomers, and lyotropic polymers.
and predict a bright future for such niaterials.
The book can be recommended for everyone with interests in mesomorphic
phases, and for those concerned with new
developments in electrooptics, information storage, sensor technology. and fibers
research.
tforst Kresse
Institut fur Physikalische Chemie
der Universitat Halle-Wittenberg ( F R G )
Chirotechnology. Industrial Synthesis
of Optically Active Compounds. By
R. A . Slieldon. Marcel Dekker, New
York, 1993. 423 pp., hardcover
$ 145.00-ISBN 0-8247-9143-6
Does stereochemistry have any particular implications for the design of an industrial chemical process, and if so, what
methodologies with scale-up potential are
available for efficient and successful manufacturing of stereoisomers? This simple
and straightforward two-fold question well
reflects the tremendously increased importance and awareness of industrially related
stereochemical issues over the past one or
two decades. The three-dimensional concept of molecular species so brilliantly conceived in the mid-1870s and assuming a
central role ever since, especially in organic
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