bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zr-and Hf-centred Lewis acid in organic synthesis
Authors: Suzuki Keisuke 
Published: November 2023

Abstract
The nature of a given Lewis acid, MLn can be modified by changing the metal (M), the ligand (L, chiral or non-chiral) as well as the charge (neutral or cationic), thereby endowing it with useful properties in organic synthesis. Early transition metals are attracting current attention to exploit their hard Lewis acidic characters. Although titanium has been studied most, recent attention is also centred at its group-4 congeners, i.e. zirconium and hafnium. Although they have been extensively used in the polymerization field,1-3 the use in organic synthesis is still rather limited either as a tailor-made catalyst or as a transient species in the course of the reaction.4 This chapter describes some unique reactivities of cationic zirconocene or hafnocene complexes, thereby dealing with four modes of functional group activation
Preparation and reaction of triorganozincates
Authors: Harada Toshiro , Oku Akira 
Published: November 2023

Abstract
Reaction of diorganozincs with organolithium or Grignard reagents produces a thermally stable ate complexes R3ZnM (M = Li, MgX) called organozincates.1·2 Organozincates are generally more reactive than organozinc halides and diorganozincs, undergoing 1,2-addition to aldehydes and ketones and 1,4- addition to conjugate enones.3 The latter reaction has been studied rather extensively and proved to be an alternative method to the use of cuprates as demonstrated in three-component coupling approach to prostaglandins. Like other ate complexes, zincates bearing a leaving group at a proper position rearrange with 1,2-migration to give homologated organozincs (Equations6.1 and 6.2).
Transition metal catalysed reactions of zinc organometallics
Authors: Knochel Paul , Jones Philip , Langer Falk 
Published: November 2023

Abstract
The low reactivity of zinc organometallic reagents can be dramatically increased by adding a transition metal catalyst. Many transition metal salts undergo transmetallation with organozinc halides or diorganozincs producing intermediate transition metal organometallics which display an enhanced reactivity toward many organic electrophiles due to the presence of d-orbitals. This increased reactivity allows many reactions not possible with conventional main group organometallic compounds to be carried out.1 The moderate activity of zinc organometallics is an essential factor for the success of these transmetallations, since it avoids the transfer of several organic groups to the same metal centre and therefore reduces the decomposition pathways avail-able of these transition metal organometallic intermediates.
Supercritical fluid chromatography
Authors: Clifford Tony 
Published: November 2023

Abstract
In chromatography, compounds are dynamically partitioned between two phases, one of which is mobile, and these compounds move with the mobile phase to an extent depending on the fraction of time they spend in it. As different compounds will partition differently, they will travel at different speeds, and so a mixture of compounds will separate as they move. For supercritical fluid chromatography (SFC), the mobile phase is a supercritical fluid and the stationary phase is a packed bed of solid material, which may have specific compounds bonded on to it, or a quartz capillary wall, which is coated with a thin layer of polymer.
Addition of electrophilic organoselenium reagents to carbon-carbon double bonds
Authors: Beaulieu Pierre l. , dáziel robert 
Published: November 2023

Abstract
Since the discovery in the late 1950s that species of the type RSeX add stereospecifically to simple alkenes, electrophilic selenium-based reagents have provided the synthetic chemist with an ever-growing arsenal of methods for the construction of complex organic molecules. Comprehensive reviews of the rich chemistry characteristic of electrophilic selenium species have appeared. In this chapter we have concentrated on the practical aspects of this chemistry, limiting ourselves to the generation and use of novel organoselenium electrophiles. Representative examples are provided of applications to carbon-oxygen, carbon-nitrogen and carbon-carbon bond formation. A final section is devoted to the growing importance of homochiral electrophilic selenium reagents and their application to asymmetric synthesis.
Free-radical reactions and reductive deselenizations
Authors: Back Thomas G 
Published: November 2023

Abstract
Several reviews of free-radical reactions of selenium compounds have appeared,1 2 and a recent monograph provides practical guidelines for freeradical reactions in general, including ones that involve selenium compounds, as well as a list of earlier reviews.3 The relative ease with which certain types of organoselenium compound undergo homolytic cleavage has provided the basis for numerous synthetically useful procedures. substrate, with generation of the corresponding alkyl or vinyl radical. Transfer of an ArSe moiety from ArSeZ to the latter species then completes the chain and regenerates Z . When a good hydrogen atom donor such as a tin hydride is present and/or selenium-group transfer is relatively slow,
X-ray diffraction broadening effects in materials characterization
Authors: Kimmel Giora , Dayan David 
Published: November 2023

Abstract
It is difficult to avoid instrumental broadening in powder diffraction and it is usually considered a drawback of this method. Therefore, the line broadening caused by structural reasons is usually ignored in routine characterization work. Nowadays, all data collection in XRPD (X-ray powder diffraction) is digitized and it is easy to perform accurate data processing. Although extensive work had been done in the last decade in the field of line-broadening analysis of XRPD there is still little agreement as to whether or not this method can be accepted as a characterization tool. The purpose of the present chapter is to demonstrate that valuable information is lost if the broadening effects are ignored.
Oxidation of the C=C bond
Authors: Ito Y N , Katsuki t. 
Published: November 2023

Abstract
Metal complexes promote catalytic epoxidation in two different ways: (i) by activation of an oxidant and subsequent migration of an oxygen from the oxidant to olefins; (ii) by oxidation of a metal ion by an oxidant to the high-valent metal oxide and subsequent oxygen transfer to olefins with the reduction of metal ion which can be reoxidized to the metal oxide in situ.The former types of reactions are catalyzed mostly by early transition metal complexes and the latter type of reactions mainly by group VII-X transition metal complexes. For example, t-butyl hydroperoxide is activated by O=V(OR)3 or O2Mo(OR)2 and undergoes epoxidation. During these reactions, the oxidation states of the vanadium and molybdenum ions do not change (Scheme 2.1.1). In general, olefins bearing a precoordinating functional group are good substrates for this type of reaction (see Section 2.3), while epoxidation of isolated olefins is rather slow. On the other hand, stereospecific epoxidation of olefins and C—H hydroxylation of alkanes are realized in living cells with the aid of oxidizing enzymes. Based on the clarification of the catalysis of an iron porphyrin complex at the active site of the representative oxidizing enzyme cytochrome P450, investigations into the enantioselective epoxidation of simple olefins with metalloporphyrin complexes or its equivalents as catalysts were commenced. The P-450-catalysed reactions transfer oxygen atoms to substrates via a high-valent oxo iron porphyrin complex that is produced by the complex redox procedure containing the enzymatic reaction with molecular oxygen. However, the formation of the same oxo species can be chemically effected by treatment of an iron porphyrin complex with stoichiometric oxidants such as iodosylbenzene (Scheme 2.1.2). Besides iron porphyrins, many other metal complexes have been found to catalyse oxygen-transfer reactions via the corresponding high-valent metal oxides.
Cooperative breeding
Authors: Payne Robert B 
Published: November 2023

Abstract
Cooperative breeding birds live in social groups. In the group some birds, the “helpers”, help rear the young of other individuals, the breeders. Helpers may provide relief to the breeders by taking part in the care of a brood, and the helpers may increase the number of brood young that survive. This behavior is curious. The helpers, by not breeding themselves, may not be behaving in their own best interest. This altruistic behavior would under most conditions be selected against, if only because other individuals would leave more offspring and the helpers themselves would fail to reproduce (Stacey and Koenig 1990, Ligon 1999). Nevertheless the New World anis and Guira Cuckoo are among the most social of all cooperative breeding birds.
Melt phase behaviour of block copolymers
Authors: Hamley Ian W 
Published: November 2023

Abstract
A remarkable property of block copolymers is their ability to self-assemble in the, melt into a variety of ordered structures with nanoscale periodicities. These structures can be controlled by varying the composition of the block copolymer or the segregation between blocks (via temperature or degree of polymerization). In addition to the now well-established lamellar (lam), hexagonal-packed cylinder (hex) and body-centred cubic (BCC) micelle phases, a number of new morphologies have been discovered, which supplement the ‘classical’ structures. The identification of a bicontinuous cubic phase of la3-d symmetry, sometimes called the gyroid phase, is now established. Other ‘perforated layer’ structures have been reported, but seem to be metastable structures formed during the transition to the gyroid structure. In this chapter, the disordered phase is abbreviated by dis.
Beyond peptide libraries
Authors: Terrett Nicholas K 
Published: November 2023

Abstract
Chapters 2 and 3 described the explosive growth in methods for the rapid synthesis of peptide libraries, primarily for immunological studies, reflecting the critical role played by solid phase peptide chemists in the initial development of combinatorial chemistry methods. Following the seminal 1991 Naturepapers from Houghton and Lam, there was an enormous growth in interest in combinatorial chemistry from the entire chemical community in general, and from pharmaceutical chemists in particular. The technology clearly had the potential to accelerate the processes involved in drug discovery, and many pharmaceutical and specialized biotechnology companies began their own investigation of combinatorial methods. Whilst most were based on solid phase methods, primarily resin beads, there was an enormous diversity in the approaches used to generate and test compounds. In addition, the drive was to apply rapid chemical methods to non-peptide structures, as these were generally accepted to be superior starting points for drug discovery programmes. Peptides are poorly absorbed if administered orally, and are subject to rapid metabolism and elimination if administered systemically (intravenously for example).
Solid phase library chemistry
Authors: Terrett Nicholas K 
Published: November 2023

Abstract
The last chapter documented the ineluctable progression away from the established solid phase synthesis of peptoids, oligonucleotides, and oligosaccharides towards the novel oligomers demanded by chemists working in combinatorial chemistry. At the end of the chapter, the synthesis of ‘peptoids’ on solid phase demonstrated that combinatorial chemistry has moved beyond the synthesis of peptide libraries towards the more complicated synthesis of low molecular weight organic molecules. These publications provided an enormous impetus to the further study of solid phase chemistry, and without doubt, in future years they will be considered to have been the watershed that set combinatorial chemistry on its path away from peptide synthesis.
Combinatorial chemistry applications
Authors: Terrett Nicholas K 
Published: November 2023

Abstract
It is impossible to give a comprehensive overview of the considerable influence and impact of combinatorial chemistry, as it is evident that the applications and successes are both numerous and varied. Furthermore, there are new and highly significant opportunities being made on a weekly basis. The objective of this chapter is to give a sense of the advantages in biology and medicinal chemistry that have resulted from a use of combinatorial libraries, describing some of the more interesting results. Many examples of combinatorial libraries have been described in the preceding chapters and to avoid repetition reference is made as appropriate to previous sections.
Introduction and some general concepts
Authors: Zard Samir Z 
Published: November 2023

Abstract
In chemistry, as in other branches of science, experiment often precedes theory. Accidental discoveries thus bring fresh light and reveal aspects of the subject hitherto unsuspected. And radical chemistry is no exception. It is therefore perhaps useful to outline, in a very broad manner, the way the field developed over the past century or so, viewed from the perspective of the synthetic organic chemist.
Organo-silicon, -germanium, and -mercury hydrides
Authors: Zard Samir Z 
Published: November 2023

Abstract
Silicon and germanium are in the same periodic column as tin, and the radical chemistry associated with these elements is in many ways qualitatively similar. The increased strength of the bonding to hydrogen and carbon translates into slower kinetics and less efficient chain processes as compared with organotin derivatives (Chatgilialoglu and Newcomb 1999). For example, hydrogen abstraction from tri n-butylgermane by a given carbon-centred radical is about 10-20 times slower than from tri-n-tributyl tin hydride (Johnston et al. 1985), and from triethylsilane and other simple silanes it becomes too slow to be generally useful.
Redox processes
Authors: Zard Samir Z 
Published: November 2023

Abstract
In essentially all the reactions we have explored so far, the radicals were generated by thermal or photochemical homolysis. There is another way to produce radicals, shown in a formal manner in Scheme 8.1. It consists in removing an electron from an electron-rich species, represented by an anion, or by adding one electron to an electron deficient entity, now represented by a cation. It is of course possible to oxidize a radical to the cation level or reduce it to the anion.
Some concluding remarks
Authors: Zard Samir Z 
Published: November 2023

Abstract
This modification of an anonymous limerick (Parrott 1983) sums up humourously a prevailing view of radical reactions that will fade away eventually when radical chemistry takes up its legitimate position in the curriculum of undergraduate and graduate students. Indeed, the foregoing chapters give only a brief glimpse of the synthetic opportunities accruing from the implementation of radical processes. It is hoped that this survey of the main reactions and methods will encourage synthetic chemists to use this powerful arsenal for solving their synthetic problems.
Low-coordinated phosphorus compounds
Authors: Asmus Sven , BergsträßEr Uwe , Heydt Heinrich , Schmitz Marion , Regitz Manfred 
Published: November 2023

Abstract
‘Phosphorus in Organic Chemistry—from Discovery to Repudiation of the Double Bond Rule’ is the title of an article summarizing the history of this essential element. Phosphorus was first mentioned by the German alchemist Hennig Brand in 1669 and recognized as an element by Lavoisier; since the beginning of the 20th century much effort has been devoted to the development of the chemistry of tri-, tetra-, and pentacoordinated compounds(σx)with tri-, tetra-, and pentavalent phosphorus(λx)centres. Milestones reached around the middle of the century were undoubtedly the olefination reactions of G. Wittig and L. Horner that have had such a decisive influence on strategies of organic synthesis.
Oligosaccharides: Their synthesis and biological roles
Authors: Osborn Helen M I , Khan Tariq H 
Published: November 2023

Abstract
Exciting developments in analytical methods have recently been reported which allow isolation and identification of previously elusive carbohydrates. As a result carbohydrates have received considerable attention from both biologists and chemists who are attempting to fully understand their biological roles. In this book we wish to portray some of the current excitement in this rapidly growing area of research and highlight some of the challenges facing carbohydrate chemists and biologists. We wish to discuss a number of modern approaches for synthesising carbohydrates so that readers of this book will feel able to contribute to this area of research. The therapeutic potential of carbohydrates will also be discussed to further illustrate their importance.
Language classification: scientific and unscientific methods
Authors: Ringe Don 
Published: November 2023

Abstract
What do we linguists have to say-or what should we have to say-about our common human inheritance? I will argue that we have less to contribute than is often supposed; but we can make some contribution, because of the way languages are usually classified. We classify languages into families, not on the basis of general similarities between them, but on the basis of shared history.
From Bench to Market: The Evolution of Chemical Synthesis
Authors: Cabri Walter , Fabio Romano Di 
Published: November 2023

Abstract
Who wins the race to turn molecules into medicines? How much does it cost? What factors influence the choice of synthetic routes and reaction mechanisms? How can pharmaceutical companies protect their discoveries? In From Bench to Market, Walter Cabri and Romano Di Fabio chart the process of industrial chemical synthesis, from the first discovery of a molecule, or 'new chemical entity', to its entry in the marketplace as a drug. They discuss all aspects related to the process research for bulk production, including comparison between different synthetic routes, key methodologies and reaction mechanisms, costs, patent competition, and crystalline forms. The authors use the real chemical history of the development of drugs from several therapeutic areas as detailed case studies, each chosen to illustrate a range of issues and methodologies in industrial chemistry. Several chapters cover the development of the various β-lactam antibiotics; two chapters describe the discovery and synthesis of the anticancer drugs Idarubicin and Paclitaxal; in another chapter, the synthesis of the anti-viral drug Acyclovir and the ‘patent war’ that resulted are explored. Between them, the authors represent considerable first-hand experience in pharmaceutical research and development. The technical, practical, and strategic information they have amassed make this essential reading for graduate and undergraduate chemists intending to work in the pharmaceutical industry, as well as for industrial chemists themselves. Lecturers teaching courses in medicinal and organic chemistry will also find it useful.
Acyclovir
Authors: Cabri Walter , Fabio Romano Di 
Published: November 2023

Abstract
The chemistry developed for the synthesis of the antiviral acyclic nucleotide acyclovir is an interesting example of competition among industrial research groups as this product is a generic drug. There are more than 20 bulk producers worldwide1 and, among them, Quimica Synthetica SA, Lachema AS, Recordati SpA, Heumann Pharma Gmbh, Solchem Italiana SpA, Cipla Ltd, Yung Zip Chemical Ind. Co., Lek Pharmac, Mallinckrodt Chemical Inc., Istituto Biologico Chemoterapico, and, of course, Burroughs-Wellcome (now Glaxo-Wellcome) have deposited a drug master file (DMF) in the USA. The high level of competition has had a dramatic effect on the price of the bulk active product and during the last 10 years there has been a process-patent war between generic companies and the originator, Glaxo-Wellcome.
Perfect Incompressible Fluids
Authors: Chemin Jean-Yves , Gallagher Isabelle , Iftimie Dragos 
Published: November 2023

Abstract
The aim of this book is to offer a direct and self-contained access to some of the new or recent results in fluid mechanics. It gives an authoritative account on the theory of the Euler equations describing a perfect incompressible fluid. First of all, the text derives the Euler equations from a variational principle, and recalls the relations on vorticity and pressure. Various weak formulations are proposed. The book then presents the tools of analysis necessary for their study: Littlewood-Paley theory, action of Fourier multipliers on L spaces, and partial differential calculus. These techniques are then used to prove various recent results concerning vortext patches or sheets, essentially the persistence of the smoothness of the boundary of a vortex patch, even if that smoothness allows singular points, as well as the existence of weak solutions of the vorticity sheet type. The text also presents properties of microlocal (analytic or Gevrey) regularity of the solutions of Euler equations, and provides links of such properties to the smoothness in time of the flow of the solution vector field.
In defence of noise
Authors: Freeman Ray 
Published: November 2023

Abstract
Our reactions to random phenomena, for example games of chance such as roulette or blackjack, are often irrational and tainted by primitive superstition. Ask the man in the street whether a penny is more or less likely to fall heads if it has just shown three tails in a row. A science student will often have difficulty deciding just how to draw a straight-line graph through data showing a large scatter of the experimental points, even though he knows in principle about least-squares-fitting procedures. Noise is somehow regarded as wrong-something to be suppressed at all costs. We may feel guilty about publishing results with large error bands or spectra with prominent noise contributions.
Chimpanzees, humans, and the forest
Authors: Boesch Christophe , Boesch-Achermann Hedwige 
Published: November 2023

Abstract
Forest scene: July 1976: Valentin, a man of the local Guéré tribe, probably about 40 years old, had the reputation of being a healer, and one who not only used natural remedies but who also relied on magic forces for his art. He was recommended to us by the park authorities as someone who could help us in setting up our first camp and in finding our way through the forest. He had his own, in our view quite unorthodox, way of doing this. Also very intriguing were the stories he told when we said that we were here to live in the forest to learn all about the chimpanzees. ‘That’s easy’, he said, ‘the old people know a lot about the chimpanzee. They say he is our brother. In the old days he was of great help to us in warfare against our neighbours. Therefore they ask us to be grateful towards him and respect him. Nobody must kill him, even if he takes some of our fruit and vegetables. Anyway, he is very clever and you never see him because there is always a guardian. But when you hear a big ‘palaver’ in the forest, you know that the head of the family is distributing nuts. ‘And do you know how they carry these nuts around?’ Valentin asked us. Of course we did not. ‘Well, they catch a monkey, take its skin and use it as a bag. Isn’t that very smart?’ Indeed, we were highly impressed and wondered whether we were dreaming. War, nuts, hunting — all the big words were there. Valentin had certainly set us thinking.