Subject historical development

It is also important to realize that chemistry is not a static body of knowledge as defined by the contents of a textbook. Chemistry came from somewhere and is at present heading in various specific directions. It is a living self-stimulating discipline, and we have tried to transmit this sense of growth and excitement by reference to the historical development of the subject when appropriate. The chemistry of the elements is presented in a logical and academically consistent way but is interspersed with additional material which illuminates, exemplifies, extends or otherwise enhances the chemistry being discussed. 

General accounts of prototropic tautomerism have been presented by Ingold and Baker" these include an outline of the historical development of the subject in which heteroaromatic compounds are discussed incidentally, and, therefore, such a historical account will not be given here. Of historical interest are Eistert s book on tautomerism and mesomerism which was published in 1938, a review on — NH-CO— tautomerism by Arndt and Eistert published in 1938, and Heller s account of heterocyclic tautomerism which appeared in 1925. Although more recent works on heterocyclic chemistry (e.g., references 9-11) have dealt incidentally with tautomerism, no unified... 

Carbonyl reactions are extremely important in chemistry and biochemistry, yet they are often given short shrift in textbooks on physical organic chemistry, partly because the subject was historically developed by the study of nucleophilic substitution at saturated carbon, and partly because carbonyl reactions are often more difhcult to study. They are generally reversible under usual conditions and involve complicated multistep mechanisms and general acid/base catalysis. In thinking about carbonyl reactions, 1 find it helpful to consider the carbonyl group as a (very) stabilized carbenium ion, with an O substituent. Then one can immediately draw on everything one has learned about carbenium ion reactivity and see that the reactivity order for carbonyl compounds ... 

The calculations described here have been called strain calculations, molecular mechanics, or force field calculations. We prefer the latter term. For a discussion of historical developments and a literature survey of earlier work, which are not given here, the reader is referred to a number of other reviews (1-3). The present paper deals with the description of force field types, techniques of energy minimisation, and procedures for the determination of force field parameters, and with some applications, preferentially taken from our own field of interest. In accordance with the experiences of the author, the work of Lifson and coworkers is given special attention other authors are nevertheless well represented in the context of critical comparisons. We hope that this selection, although inevitably biased, will help to improve the consistency of the presentation of the subject. 

In order to understand the principles involved in electron-transfer catalysis and also in order to appreciate the historical development of the subject, we must treat hole catalysis and electron transfer between metal atoms and ions and organic substrates before examining catalytic reactions in more detail. This review is intended to cover the basic principles involved in these three areas and to provide a conceptual framework for electron-transfer catalysis. 

I have felt that in writing on this complex subject my primary duty hould be to present the theory of the chemical bond (from my point of view) in as straightforward a way as possible, relegating the historical development of the subject to a secondary place Many references are included to early work in this field the papers on the electronic theory of valence published during the last twenty years are so numerous, however, and often represent such small differences of opinion as to make the discussion of all of them unnecessary and even undesirable. 

The hydrolysis and formation of esters in solutions of strong acids show very varied behaviour, and depend on a rather large number of different factors. Our understanding of the quantitative behaviour of these reactions has become much clearer in recent years, and since an attempt to follow the historical development of the subject might obscure parts of the pattern that has emerged, it seems best to base a discussion on recent results. 

Before proceeding further on this subject it might be interesting to review the historical development of pressure measurements in ordnance... 

This brief outline of historical developments in osmium tetroxide-mediated olefin hydroxy-lation brings us to our main subject, catalytic asymmetric dihydroxylation. The transition from stoichiometric to catalytic asymmetric dihydroxylation was made in 1987 with the discovery by Sharpless and co-workers that the stoichiometric process became catalytic when N-methyl-... 

A symposium in print, Physical Organic Chemistry for the 21st Century, has appeared under the auspices of IUPAC Commission III.2.439 Some twenty distinguished authors or groups of authors have tried to foresee the way in which the various parts of the subject may develop in the next decade or so. Tidwell has provided a prologue on the first century of physical organic chemistry and many of the articles reflect on the historical development of the subject. 

However, an encyclopaedia focusing on instruments, which includes material on chemical instruments and apparatus, was published in 1998. It incorporates 327 entries on a diverse range of historical items.4 Its strengths are its fairly comprehensive coverage and inclusion of more recent and complex instruments. Descriptions of the historical development of each item are necessarily short. Though it does not concentrate particularly on chemistry, there is some useful material to be found in a German volume of 37 essays, including a chapter on a subject rarely treated, industrial reaction vessels.5... 

We are also witnessing a considerable increase in new specialized literature. The most important of these is the standard work Twin Screw Extrusion by J. L. White [44]. It is a rich source of information, both about the historical development and the state-of-the-art technology, as well as about patent literature and specialized publications. A few examples [45,46] from the wide-ranging specialized literature on the subject of co-rotating extruders should be mentioned here. 

Within the format of this contribution, only a brief outline of ftie vast range of P-donor ligand architecture can be given. Most of the examples given are based upon P-C bonding, which reflects flie historical development of the subject. 

This review does not attempt an exhaustive survey of all NMR work on catalysts, and its reference list is not a suitable guide to the historical development of the general subject. Papers on adsorbate NMR have typically been selected because they address some specific aspect of metallic behavior (or a pointed lack of it). Due to the availability of additional information, the reasoning and the interpretation of results given here are sometimes different from those in the original papers. 

The position of attachment of the phosphoric add to the ribose residue in the ribosenucleotides. In order to understand the historical development of this aspect of the subject it is necessary first to discuss the chemistry of two ribose nucleotides which, although of great biochemical importance, are not components of ribosenucleic acid. They are both purine nucleotides and both occur free in Nature. 

Many thousands of papers have been written on the subject of this review, of which only a small fraction can l)e cited here. The aim has been to give some idea of the historical development of our knowledge, followed by a detailed statement of the present state of that knowledge. The main emphasis has been laid on those pathways which appear to account for the greater part of normal aromatic amino acid metabolism in man subsidiary pathways are dealt with more briefly. An attempt has been made to cover relevant papers received in England up to the end of 1954. 

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