bluuebunny/crossref_metadata_2025 huggingface dataset:
Solutions Of The Boltzmann Equation
Authors: Mccourt Frederick R W , Beenakker Jan J M , Köhler Walter E , Kuščer Ivan
Published: November 2023

It often happens in theoretical physics that equations are much easier to derive than to solve. Such is certainly the fate of the nonlinear Boltzmann equation for which, after more than a hundred years, the equilibrium solution is still the only known exact solution of general validity. Fortunately, this has not hindered anyone from attempting to obtain solutions numerically via step-by-step integration in time, starting with given initial conditions. In view of the many variables involved, any such task is formidable even for modern computers. Stationary solutions are even harder to find. If general physical insight is sought, we still require approximations based upon simplifying assumptions.
Solution Of Generalized Boltzmann Equations
Authors: Mccourt Frederick R W , Beenakker Jan J M , Köhler Walter E , Kuščer Ivan
Published: November 2023

In Chapter 4, we examined the classical and quantum mechanical generalizations of the Boltzmann equation needed for the treatment of transport and relaxation phenomena in a gas of rotating molecules.
Spectroscopic Phenomena
Authors: Mccourt Frederick R W , Beenakker Jan J M , Köhler Walter E , Kuščer Ivan
Published: November 2023

Radio-frequency radiation can be used to probe the relaxation of macroscopic nuclear magnetizations in a gas, which occurs either directly via the effect of collisions on individual nuclear spins (as in a monatomic gas) or indirectly via collisional reorientation of the molecular rotational angular momentum (which is weakly coupled to the nuclear spins). As described in § 11.1, nuclear spin relaxation provides a sensitive probe of intermolecular interactions, but it is a difficult experiment to carry out and it does require the presence of a nuclide having non-zero spin. Information obtained from nuclear spin relaxation studies is in many cases complementary to that obtained from depolarized Rayleigh light scattering measurements.
Introduction
Authors: Koningsveld R , Stockmayer W H , Nies E
Published: November 2023

As already emphasized in the Preface, phase transformations play a very important role in polymer science and engineering. Phase separation is the essential feature of classical as well as some modern methods of polymer fractionation, such as temperature-rising elution fractionation of partially crystalline polymers. Another example is presented by the fractionation of copolymers with respect to both chain length and chemical composition. Demixing may further have appreciable effects during polymerization, blending, and compounding processes. Partially crystalline polymers owe their stiffness and strength to regions of crystalline order. Phase behaviour determines the morphology of the material to a considerable extent, so that mechanical properties of polymer blends, block copolymers, and composites are found to be enormously dependent on phase relationships. Partial miscibility also plays important roles in biology and medicine, as for example in the formation of cataracts in eye lenses, protein separations, and fibril formation related to Alzheimer’s disease.
Interactions
Authors: Bruch L W , Cole Milton W , Zaremba Eugene
Published: November 2023

The properties of adsorbed layers are ultimately determined by the interactions among the constituents. These interactions are fundamental to a broad range of adsorption phenomena, including the equilibrium structures of the adsorbate, the phases that exist as a function of temperature and density, and surface kinetics. In this chapter, we develop the concepts that are central to understanding the forces acting in physical adsorption and review the progress that has been made in determining these forces from a priori theories or from semiempirical and empirical constructions using experimental data. Monographs on intermolecular forces include the books of Margenau and Kestner (1971), Mahanty and Ninham (1976), Israelachvili (1992), Stone (1996), and of Hirschfelder, Curtiss, and Bird (1964). Reviews of the forces in physical adsorption include Nicholson and Parsonage (1982), Bruch (1983a), Vidali et al.(1991), and Steele (1993).
Monolayer Films: Theoretical Context
Authors: Bruch L W , Cole Milton W , Zaremba Eugene
Published: November 2023

The development of scientific concepts usually proceeds from the simple to the complex. We now follow such a route in presenting the theory of monolayer adsorption. This chapter provides an introduction to the theory; Chapters 5 and 6 provide a more detailed description of the theory and a discussion of illustrative examples of film behavior, respectively. Three principal lines of conceptual development have strongly influenced the goals of theoretical efforts for monolayers and also have set a context in which most of the experiments have been analyzed.
Challenges in Synthetic Organic Chemistry
Authors: Mukaiyama Teruaki
Published: November 2023

This book gives a much-needed account of the work of one of Japan's most important synthetic organic chemists, Teruaki Mukaiyama, providing an insight into his approach to synthetic problems and the development of new synthetic methods. Early chapters record research into a wide range of reactions, including dehydration reactions, the use of organosulfur compounds, and oxidation-reduction condensations in peptide and nucleotide synthesis. The second part of the book looks at the development of novel synthetic reagents, and includes an account of Mukaiyama's important work on the applications of titanium compounds in organic synthesis. Synthetic control is covered in the final chapters. All those working in organic synthesis will find this book of interest. It makes accessible much work which has hitherto been available only in the Japanese literature, and provides a unique account of the work of one of the world's leading synthetic organic chemists.
Chemical Oscillations and Instabilities
Authors: Gray Peter , Scott Stephen K
Published: November 2023

Scientists in many fields are now expressing considerable interest in non-linearity and the ideas of oscillations and chaos. Chemical reactions provide perfect examples of these phenomena since oscillating reactions, explosions, ignition, travelling waves, patterns, quasiperiodicity, and chaos are all features of chemical kinetics. This book introduces non-linear phenomena in chemical kinetics using simple model schemes. These models involve chemical feedback, such as chain branching, autocatalysis, and self-heating. The emphasis is on physical and pictorial representation, and on identifying those gross features which are essential. The experimental conditions under which such behaviour will occur can be predicted using simple mathematical recipes, and these are also included. The first part of the book begins with a discussion of long-lived oscillations for autocatalytic or exothermic reactions in closed vessels. Stationary states, bistability, and oscillations in continuous flow reactors and diffusion cells are then considered. This is followed by chemical wave propagation and by pattern selection and formation. Heterogeneous reactions are discussed, as they can also exhibit bistability and oscillations. Complex oscillations, quasiperiodicity, and chemical chaos, either forced or spontaneous, are introduced. Part 2 deals with real experimental systems, describing observed experimental behaviour and its interpretation in terms of the underlying chemical mechanisms or simplified models. The Belousov-Zhabotinskii reaction is discussed in some detail as the most extensively studied system, and the behaviour of important gas phase reactions is presented.
Oscillations In A Closed Isothermal System
Authors: Gray Peter , Scott Stephen K
Published: November 2023

This chapter introduces the simplest chemical kinetic scheme for an isothermal oscillatory reaction in a closed system. This model scheme is used to illustrate concepts of very general importance and applicability. A mathematically deeper analysis is given in chapter 3.
A Utoca T Al Ytic Reactions In Plug-Flow And Diffusion Reactors
Authors: Gray Peter , Scott Stephen K
Published: November 2023

Well-stirred systems are particularly convenient for the theoretician but are often less easy to realize in practice. Indeed, spatial inhomogeneities, with consequent molecular diffusion or thermal conduction processes, arise in many important situations--as varied as a single biological cell and a haystack. In the next three chapters we turn to unstirred systems, again seeking to determine ‘bifurcation’ phenomena driven by non-linear kinetics.
Complex Oscillations And Chemical Chaos
Authors: Gray Peter , Scott Stephen K
Published: November 2023

We have concentrated on two-variable examples hitherto because so many of the key features of oscillatory behaviour can be vividly portrayed in these terms. However, real systems all have more numerous chemical constituents and may give more complex responses than those illustrated previously. The inclusion of a third variable or varying one of the parameters of the system in time takes us to new complexities, and these are now examined. After a careful study the reader should be able to:
Dynamic Processes Studied by Two-Dimensional Exchange Spectroscopy
Authors: Ernst Richard R , Bodenhausen Geoffrey , Wokaun Alexander
Published: November 2023

The investigation of dynamic processes such as chemical exchange, cross-relaxation, nuclear Overhauser effects, spin diffusion, and cross-polarization by 2D spectroscopy has a number of advantages over the ID techniques discussed in § 4.6.1.4, particularly when the system comprises an extended network of exchange processes that occur simultaneously. The 2D methods are most useful for studying slow dynamic processes with rates that are too low to affect the lineshapes. Two-dimensional exchange spectroscopy is therefore particularly well suited for studies of cross-relaxation (transient Overhauser effects) and of spin diffusion in solids. In applications to chemical exchange, the information content of 2D exchange spectra is greatest if the temperature is chosen such that the exchange rate is fast compared to longitudinal relaxation and slow compared to the spectral parameters affected by the exchange.
Expressions for Effective Cross Sections
Authors: Mccourt Frederick R W , Beenakker Jan J M , Kohler Walter E , Kuscer Ivan
Published: November 2023

We have used the concept of effective cross sections extensively in previous chapters to analyze field-free transport properties (Ch. 6), field-effects on transport properties (Chs. 7, 8), optical phenomena (Ch. 9), and relaxation phenomena (Chs. 10, 11). Ultimately, we wish to be able to utilize effective cross section data in order to obtain detailed descriptions of intermolecular interactions for various molecules. In order to do this efficiently, it is important to know which effective cross sections provide independent pieces of information related to the interaction potential, and which ones, because they can be obtained as linear combinations of other effective cross sections, are useful principally as checks on the accuracy and consistency of the others.
The Near-Hydrodynamic Regime
Authors: Mccourt Frederick R W , Beenakker Jan J M , Kohler Walter E , Kuscer Ivan
Published: November 2023

In previous chapters where we were concerned with the hydrodynamic regime, theory was sufficiently developed and complete that discussion of the experimental results was straightforward. For the near hydrodynamic regime, however, where boundary layers and Burnett effects both play a role, the situation is quite different. For this reason, it is important to establish the experimental facts so far as possible independently of specific theoretical approaches. Indeed, the value of various phenomenological theories can only be established by looking at their success or failure with respect to all available reliable experimental data.
Tables of Transport Coefficients and Effective Cross Sections
Authors: Mccourt Frederick R W , Beenakker Jan J M , Kohler Walter E , Kuscer Ivan
Published: November 2023

We have seen in Chs. 2, 5-7, 10, 11 that the various transport and relaxation phenomena can be expressed in terms of effective cross sections. These effective cross sections contain all the relevant information related to the intermolecular interaction. It is therefore often convenient to give values of relevant cross sections extracted from experimental measurements together with, or even instead of, the transport coefficients or the relaxation parameters themselves.
Elementary Description Of Nmr
Authors: Goldman Maurice
Published: November 2023

In this introductory chapter, we recall a number of basic facts of NMR which are supposedly familiar to the reader, and which use the simplest possible theoretical tools. This chapter is self-contained and is in essence a simplified version of Chapters I to III of Abragam’s Principles of nuclear magnetism (1961).
Generalities On 2D Spectroscopy. J Spectroscopy
Authors: Goldman Maurice
Published: November 2023

This is the first of three chapters devoted to the description of 2D spectroscopy and related methods. These methods have produced a qualitative change in NMR spectroscopy, both in liquids and in solids, through the numerous and versatile ways they provide for tackling spin systems and extracting information on their nuclear magnetic properties, and from there on the structural, conformational and dynamic properties of the molecules to which the nuclear spins belong. In particular in liquids, it is only with these methods that NMR spectroscopy can be extended to the detailed study of the large molecules of biological systems, which has turned NMR into a fundamental tool in the fields of biochemistry and molecular biology.
α-Substitution using chiral enolates
Authors: Procter Garry
Published: November 2023

Substitution at the a position of chiral enolates is a large and important area of asymmetric synthesis, which has been thoroughly reviewed. This chapter is concerned mainly with the alkylation of enolates which are chiral by virtue of being attached to a chiral auxiliary (see Chapter 2) or an equivalent. Nevertheless the general principles involved can be extended to the reactions of other enolates as the concepts which are used to account for the stereoselectivity of alkylation of such enolates can be applied to the reactions of other enolates.
CRYSTALS - a programmable program
Authors: Watkin D J
Published: November 2023

A program is only useful if people use it, and people do not like using new or difficult programs. My greatest pleasure when starting to use a PC clone was discovering a VAX EDT emulator for it. This resistance to change and complexity is common, and presents the programmer with a difficult challenge. There are various partial solutions to the problem. One is to leave the user with few options, in the belief that the efficacy of the program is unlikely to be increased by giving the user control over the intimate workings of the program. This policy works well when the domain of operation of the program is small, and has been exhaustively researched. Modern direct-methods programs are crystallographic examples from this class, where the run-time intervention required by the user is now reduced to almost nothing. Programs like this are good candidates for background computation.
Elimination and addition-elimination reactions
Authors: Westwell Andrew D , Williams Jonathan M J
Published: November 2023

When two groups are lost from adjacent atoms to form an alkene the process is known as (3-elimination. This type of reaction can be readily divided into two major categories, depending on the species eliminated. Thus, alkenes may be formed by the elimination of H-X (type 1) or X-X (type 2) as shown in Scheme 5.1. Type 1 and type 2 reactions will be treated separately, and a final section will be concerned with the synthesis of alkenes via addition of enolates to carbonyl compounds followed by dehydration.
NMR and diaphragm-cell techniques for the study of molecular dynamics in fluids
Authors: Price W E , Lüdemann H D
Published: November 2023

Nuclear-magnetic-resonance (NMR) spectroscopy has, arguably, become the most powerful and important analytical tool for structural elucidation of chemical compounds. It has completely revolutionized whole areas of chemistry and biochemistry. So it is perhaps not surprising that modern Fouriertransform (FT-NMR) spectroscopy also plays a central role in studies which focus upon intermolecular interactions, dynamics, and their effects upon the fluid state. The importance of FT-NMR spectroscopy in high-pressure molecular-dynamics experiments is due to its noninvasive nature and its versatility; a number of different parameters may be determined to describe various aspects of the motions and intermolecular forces within a system. With a number of modifications to facilitate the application of elevated pressures the whole gamut of modern FT-NMR spectroscopy is potentially available. A detailed description of the theory and the methods will not be given here, since an outline is sufficient for the present purpose; many scholarly expositions are available on the subject, to which readers are directed.1-3 In addition, Section 3 gives a brief description of the range of measurements which can be made using high-pressure NMR techniques based on recent work.
X-ray synchrotron and neutron radiation studies of polycrystalline molecular compounds
Authors: Willis B T M
Published: November 2023

In recent years X-ray synchrotron radiation and pulsed neutron radiation have been used in the study of organic crystal systems. In this paper we shall describe one such study with X-rays (cimetidine) and two studies with neutrons (fullerene and 4-methyl pyridine oxide). All three studies were carried out on powdered samples and gave results which demonstrate the power of high-resolution instruments in solving structural problems in organic crystal chemistry.
Dynamical structure analysis of isomerization in the crystalline state
Authors: Ohashi Yuji
Published: November 2023

A single-crystal-to-single-crystal transformation is very attractive because both structures of the reactant and product are obtained by X-ray analysis using only one crystal. The topochemical process can easily be envisaged. Typical examples reported so far are the [2+2] photocyclo-addition of 2,5-distyrylpyradine (Nakanishi et al. 1977), the photopolymerization of diacetylene derivatives (Enkelmann et al. 1980), the [2+2] photodimerization of 5-benzylidene cyclopentanones (Nakanishi et al 1981), and the thermal dimerization of o-benzenedithiol cobalt complex (Miller et al. 1983). In all cases the reactions proceed while almost retaining the single crystal form and the movement of each atom can be presumed from the structures before and after the reaction. The composite diagram of the reactant and product structures is very informative. However, the reaction does not always proceed smoothly, that is, obeying first-order kinetics, from the initial stage to the final stage. Determination of the structures at several intermediate stages are essential for elucidating the reaction process. Moreover, a systematic analysis of related crystals is necessary to obtain a quantitative mechanism.
Conformational preferences of (R,R)tartaric acid esters and amides: hydrogen bonding and packing in crystals
Authors: Szczepańska B , Rychlewska U
Published: November 2023

Tartaric acid and its derivatives have long played an important role in the development of organic and pharmaceutical chemistry. Optically active tartaric acid and its 0,0-dibenzoyl derivatives have been used successfully as resolving agents for racemic mixtures and recently (R,R)-tartaric acid diamides have been applied for this purpose (Dobashi, Hara & Iitaka, 1988). This group of compounds has been extensively studied by X-ray crystallography (more than 200 entries are available in the Cambridge Crystallographic Data File). However great in number, crystal structure analyses are limited to various forms of tartaric acid, its metallic and other salts and to compounds containing coordinated tartrate or tartramide ligands. Since, on the other hand, few structural data are available for uncomplexed (R,R)-tartaric acid esters and amides, we have undertaken X-ray studies on this group of compounds. In view of the common use of some of these compounds as resolving agents, investigation of the possible mechanism of their self-association might be of significance. For most of the molecules in question, the dominant mechanism is hydrogen bonding.
Aza-oxa crowns
Authors: Parker David
Published: November 2023

The saturated aza-oxa crown ethers were first synthesised as intermediates in the synthesis of the nitrogen cryptands. The reaction conditions used for the formation of these macrocycles involved the high-dilution technique. In this versatile method, a diamine and a diacid chloride are simultaneously added in the presence of triethylamine to a large volume of solvent, usually toluene, over an extended period of time. The major product from such a reaction is the [1+1] cyclised product, although the [2+2] adduct can often be isolated as well, in low yield. Whilst this method is still sometimes used, particularly for cryptand synthesis (Chapter 5), it has been superseded by methods that are more convenient and which proceed under medium dilution.
Matrix isolation-an introduction to the technique
Authors: Dunkin Ian R
Published: November 2023

In the most general sense, matrix isolation comprises a range of experimental techniques in which guest molecules or atoms are trapped in rigid host materials. The trapped species are prevented from diffusing, and cannot therefore undergo any bimolecular reactions, except with the host (Fig. 1.1). The host material can be a crystalline solid, a polymer, or a glass formed by freezing a liquid or solidifying a gas. The term matrix isolation is, however, most commonly used in a narrower sense: to refer to the technique of trapping molecules or atoms in solidified inert (or occasionally reactive) gases-a technique requiring very low temperatures.
distributed multipole expansions
Authors: Stone A J
Published: November 2023

For those readers accustomed to the concept of radius of convergence as it applies to a series in powers of a complex variable, it is worth emphasising that we are dealing here with a series in powers of 1/ R. For this reason, the interior of the sphere describes the region where the series diverges, and we shall use the term ‘divergence sphere’ to emphasize this fact. In contrast to the case of a circle of convergence in the theory of complex variables, which one wishes to be as large as possible, we require the spheres of divergence to be as small as possible for optimum convergence.
Practical Models For Intermolecular Potentials
Authors: Stone A J
Published: November 2023

The computation of the interaction energy ab initio is very time-consuming, whether it is done by perturbation theory or the supermolecule method, and it is not practical in many applications. In molecular dynamics, for instance, it is necessary to calculate the forces and torques on all the molecules in an assembly of several hundred, in order to obtain the equations of motion, and this has to be repeated for each step in the simulation, which typically requires 105 or 106 steps. For this sort of problem, we usually need to use much simpler models of the interaction. For the most basic properties of condensed phases, it is sufficient to use extremely simple models-for example, the hard-sphere model provided much useful information about the behaviour of inert-gas liquids-but if we want more detailed information, we have to use better models.
Total Synthesis of (±)-Leuhistin
Authors: Hecker S J , Werner, K M
Published: November 2023

Discussion Points Suggest a possible reason for the selectivity observed in step e. Explain the migration of the benzoate group observed in transforming compound 4 into 5. Further Reading For the use of activated alumina in the synthesis of 3-oxoesters, see: D. D. Dhavale, P. N. Patil and R. S. Raghao, J. Chem. Res., Synop.,1994, 4,152. For reviews on catalytic transfer hydrogenation, see: R. A. Johnstone, A. H. Wilby and I. D. Entwistle, Chem. Rev.,1985, 85,129; G. Brieger and T. J. Nestrick, Chem. Rev.,1974, 74,567.
Total Synthesis of 1233A
Authors: Wovkulich P M , Shankaran K , Kigiel J , Uskokovic, M R
Published: November 2023

Discussion. Points Total Synthesis of 1233A What is the mechanism of the Noyori catalyst-mediated asymmetric hydrogenation step a? Explain the diastereoselectivity observed in the [2,3]-rearrangement of step i. During the hydroboration step, a substantial amount of compound 13 was formed. Suggest a way to convert it into the desired epimer 8 by exploiting the latent symmetry of the system. Further Reading For the influence of trace amount of acid in the ruthenium (11)-BINAP catalysed asymmetric hydrogenation, see: S. A. King, A. S. Thompson, A. O. King and R. T. Verhoeven, J. Org. Chem.,1992, 57, 6689. For a review on enantioselective catalysis with transition metal compounds, see: H. Brunner, Quim. Nova,1995, 18,603. For reviews on the [2,3]-Wittig sigmatropic rearrangement, see: K. Mikami and T. Nakai, Synthesis,1991, 8,594; K. Mikami and T. Nakai, Chem. Rev,1986, 86,885. For a review on the carbometalation of alkynes, see: E. Negishi, Pure Appl. Chem.,1981, 53,2333.
Enantioselective Total Synthesis of (-–)-7- Deacetoxyalcyonin Acetate
Authors: MacMillan D W C , Overman, L E
Published: November 2023

Discussion Points Suggest a structure for compound 4 and a possible way of synthesising it from 14. Explain the stereoselectivity observed in step e. Suggest a mechanism for the formation of compound 7. Which enantiomer of diethyl tartrate is necessary to use in order to obtain compound 9? Give an explanation of the regioselectivity obtained in the epoxide reduction of step k. Further Reading For another application of the Prins-pinacol rearrangement, see: G. C. Hirst, T. 0. Johnson and H. E. Overman, J. Am. Chem. Soc.,1993, 115,2992. For a recent review on the Sharpless epoxidation reaction, see: A. D. Gupta, D. Bhuniya and V. K. Singh, J. Indian Inst. Sci.,1994, 74,71. For a review on the Nozaki-Hiyama reaction, see: P. Cintas, Synthesis, 1992, 248. For a review of the use of TPAP as a catalytic oxidant, see: S. V. Ley, J. Norman, W. P. Griffith and S. P. Marsden, Synthesis,1994, 639.
Total Synthesis of (+)-Stoechospermol
Authors: Tanaka M , Tomioka K , Koga, K
Published: November 2023

Discussion Points What is the mechanism of step b? Bearing in mind the fact that the 1:1 diastereomeric mixture 2 gave an approximately 1:1 mixture of isomers 3 and 4, rationalise the stereoselectivity of the reaction and the formation of the four new chiral centres. Propose a reaction sequence which could convert the dilactone isomer 4 into compound 7. What is the mechanism of the reduction with hydrazine hydrate in steps k ands? In step w, DIBAL-H is used to reduce an cx,(3-unsaturated ketone to an allylic alcohol. What reagent is usually used for such a transformation? Explain the stereoselectivity of this step. In the epoxidation of compound 14, why is the cx-epoxide the major isomer? In step e’, a tosylate is sucessfully displaced by an incoming malonate nucleophile with inversion of configuration. What is a potentially significant side-reaction when treating secondary tosylates with more basic nucleophiles? Suggest a mechanism for the reduction step f’. Further Reading A racemic approach to stoechospermol has also been reported recently: M. Miesch, A. Cotte and M. Franck-Neumarm, Tetrahedron Lett.,1994, 35,7031.
Total Synthesis of (+)-Carbonolide B
Authors: Keck G E , Palani A , McHardy, S F
Published: November 2023

Discussion Points The workup of step b includes washing with a saturated solution of Rochelle’s salt. What is the purpose of this process? Suggest a structure for compound S. Rationalise the stereochemistry of the nucleophilic attack on compound 4 in step e. What role does the magnesium bromide etherate play in the stereocontrol? Propose a short synthesis of the alcohol used to esterify compound 10 starting from commercially available (R)-ethyl (3-hydroxybutyrate. Further Reading For a review of macrocyclic ring formation methods, see: Q. C. Meng and M. Hesse, Top. Curr. Chem.,1991, 161,107. For a review of the use of tetrapropylammonium perruthenate (TPAP) see: S. V. Ley, J. Norman, W. P. Griffith and S. P. Marsden, Synthesis, 1994, 639. For a review, in English, of computer-aided conformational design in macrolide synthesis (including carbonolides) see: 0. Yonemitsu, Yuki Gosei Kagaku Kyokaishi,1994, 52,946. The use of ultrasound to accelerate the hydroboration of double bonds has also recently been reported by H. Oguri, S. Hishiyama, T. Oishi and M. Hirama, Synlett,1994, 1252. For a more general review on the application of ultrasound to synthesis see: C. Einhorn, J. Einhorn and J.-L. Luche, Synthesis,1989, 787.
Total Synthesis of Stenine
Authors: Chen C -Y , Hart, D J
Published: November 2023

Discussion Points Propose a structure for the other potential diastereoisomer arising from the intramolecular Diels-Alder cycloaddition. What is the mechanism of the Hoffman-type degradation of step f? A substantial amount of compound 14 is recovered if the Claisen rearrangement is attempted without selective protection of the primary hydroxyl group formed in step p. Further Reading For a review on diastereoselective Claisen rearrangements, see: H.J. Altenbach, Org. Synth. Highlights,1991, 115. For a study of Diels-Alder reaction on trienic esters in the absence and presence of a Lewis acid catalyst, see: M. Toyota, Y. Wada and K. Fukumoto, Heterocycles,1993, 35,111. For a recent NMR study of Lewis acid stoichiometry in Diels-Alder reactions, see: I. R. Hunt, C. Rogers, S. Woo, A. Rauk and B. A. Keay, J. Am. Chem. Soc., 1995, 117, 1049; I. A. Hunt, A. Rauk and B. A. Keay, J. Org. Chem.,1996, 61,751. For a recent article on iodolactonisation leading to 7- to 12-membered ring lactones, see: B. Simonot and G. Rousseau, J. Org. Chem.,1994, 59,5912.
The Total Synthesis of (+)-Adrenosterone
Authors: Dzierba C D , Zandi K S , Mollers T , She.a, K J
Published: November 2023

Discussion Points When ethylene glycol was used instead of (-)-hydroxybenzoin (step e) in the preparation of the silicon tether, the intramolecular Diels-Alder reaction of step h proceeded with reverse diastereoselectivity, affording a mixture corresponding to 6:7 in a 1:10 ratio. Give an explanation for this finding. Further Reading For a review on silicon-tethered reactions, see: M. Bois and T. Skrydstrup, Chem. Rev.,1995, 95,1253.
Total Synthesis of (+)-7-Deoxypancratistatin
Authors: Keck G E , McHardy S F , Murry, J A
Published: November 2023

Discussion Points What is the mechanism of step i? The stereochemical outcome of the radical cyclisation step o is highly dependent on the use of a cyclic precursor (e.g. 7). When acyclic compound 12 was submitted to the same reaction conditions as in o, it cyclised to give 13. Give reasons for this finding.
Total Synthesis of (3Z)-Dactomelyne
Authors: Lee E , Park C M , Yun, J S
Published: November 2023

Discussion Points Explain the mechanism of step b. Explain the cis-2,6-selectivity observed in the radical cyclisation steps h and s. The gem-dichloro derivative obtained in step h could only be reduced stereoselectively with the use of a (trimethylsilyl)silane-triethylborane system. A variety of other systems only led to mixtures. Suggest a possible reason for this finding. Give a reason for the regioselectivity observed in the reductive cleavage of the benzylidene group in step I. In the radical cyclisation step s, none of the epimeric bromide was formed. When the reaction is applied to the synthesis of monocyclic products mixtures of epimers are usually obtained. Give an explanation for this difference in stereoselectivity. What is the mechanism of the Py•SO3 oxidation? Explain the selective formation of the Z double bond in 12.
Synthesis of a Vindorosine Precursor
Authors: Winkler J D , Scott R D , Williard, P G
Published: November 2023

Discussion Points What is the mechanism of the protection sequence a, b? Explain the steroselectivities observed in the photochemical reaction of step f and in the Mannich reaction step g. What is the purpose of tetrabutylammonium fluoride in step h? What is the byproduct of step k? Further Reading For reviews on tandem reaction in the synthesis of natural products, see P. J. Parsons, C. S. Penkett and A. J. Shell, Chem. Rev.,1996, 96,195; J. D. Winkler, C. M. Bowen and F. Liotta, Chem. Rev.,1995, 95,2003.
Total Synthesis of (–)-Parvifforin
Authors: Hoye T R , Ye, Z
Published: November 2023

Discussion Points What kind of symmetry do the molecules from 4 to 6 and from 9 to 15 possess? Which isomer of diethyl tartrate would be expected to give the desired product in step e? In steps i and j the diol 5 is transformed into its corresponding bis­epoxide 6. What product could reasonably have been expected had 5 been first desilylated, then treated as in steps o to q?
The International Classification of Headache Disorders (ICHD)*
Authors: Olesen J
Published: November 2023

Undoubtedly, most physicians consider disease classification to be boring, impossible to learn by heart, and clinically not very useful. This may be true in the sense that practicing physicians do not know classifications or diagnostic criteria by heart and do not even have time to look the criteria up except in special cases. However, we are all working on the basis of some sort of classification and use some sort of diagnostic criteria, often without knowing it.
Discussion Summary, the Secondary Headaches: Part II
Authors: Olesen J
Published: November 2023

The new entity cerebral venous sinus stenosis has been diagnosed in patients with the new persisting headache and increased intracranial pressure by lumbar puncture. In such patients, a stenosis of one or both of the transverse sinuses has been demonstrated. In the experience of Professor Diener, some of these cases were cured by balloon dilatation while, in others, it was not possible to dilate the sinus. The syndrome is still too new to give further details about clinical characteristics and treatment results.
French Survey Network on Headaches and Facial Pains
Authors: Lantéri-Minet M , Autret A , Baudesson G , Bousser M G , Creach’ C , Donnet A , Dousset V , Fabre N , Giraud G , Guégan-Massardier E , Guy N , Lucas C , Massiou H , Mick G , Navez M , Pradalier A , Radat F , Valade D , Géraud G
Published: November 2023

The Société Française d’Etudes des Migraines et Céphalées (SFEMC), i.e French Headache Society, sets up a survey network on headaches and facial pains based on International Headache Society diagnostic classification. We present the main purposes of the network, the methodology, the results after one year, and prospective for 2004.
Microbes In The Pathogenesis Of Rheumatoid Arthritis
Authors: Toivanen Paavo
Published: November 2023

Many diverse concepts and speculations related to the etiopathogenesis of rheumatoid arthritis have been proposed, most of which implicate both genetic and environmental factors. The disease is known to be associated with certain HLA-DRB1 alleles, encoding a common sequence of five amino acids in the hypervariable region of the HLA-DR chain, the so-called susceptibility epitope. This epitope is found in 80–90% of Caucasoid patients with rheumatoid arthritis and in 40–50% of non-rheumatoid subjects. Disease heritability is estimated to be about 60%, of which HLA accounts for less than a half, and multiple loci outside the HLA region are responsible for the rest . Several alternative possibilities have been proposed for the participation of the susceptibility epitope , the most common being that it specifies HLA-DR molecules binding arthritogenic peptides. Recently it has become apparent that bacterial colonization of the host could be determined by genetic factors, including HLA, leaving a novel role also for the susceptibility epitope .
The Role Of T Lymphocytes In Rheumatoid Arthritis
Authors: Fox David A
Published: November 2023

The concept that T cells might be important to the pathogenesis of rheumatoid arthritis (RA) is relatively recent. It was little more than 25 years ago that initial evidence was provided that the preponderance of lymphocytes in synovial tissue were in fact T cells, and not antibody-producing cells. A detailed understanding of T cell biology began to take shape in the 1980s, in large part due to the development of monoclonal antibodies against a variety of lymphocyte surface structures. In parallel with these advances in basic immunology, the hypothesis for a central role of T lymphocytes in a variety of immune-mediated diseases, such as rheumatoid arthritis, begin to take shape . Data from animal models and from genetic studies were also important factors in the development of a ‘T cell hypothesis’ for the pathogenesis of RA.
Angiogenesis And Cell Trafficking
Authors: Buckley Christopher D , Filer, Andrew , Pitzalis Costantino
Published: November 2023

Histologically, the rheumatoid synovium is characterized by a number of defining factors. Critical amongst these are lining layer hyperplasia, accompanied by significant new capillary growth from existing blood vessels (angiogenesis), and infiltration of the hypertrophied synovium by specific, well-defined populations of mononuclear leukocytes. Antigenic vessel formation occurs in the rheumatoid arthritis (RA) synovium, and is considered to be pivotal to the early development and persistence of disease, maintaining supplies of nutrients and cytokines to the expanded lining layer and pannus tissue . Furthermore, the expanded endothelial cell population generated during angiogenesis performs a number of important pathological roles, including cytokine production, coagulation, antigen presentation, and leukocyte recruitment .
Nsaids And Analgesics
Authors: Day Richard O , March Lynette M , Graham Garry G , Scott, Kieran F , Williams Kenneth M
Published: November 2023

The non-steroidal anti-inflammatory drugs (NSAIDs) and related drugs can be divided into two major groups (reviewed in Refs 1 and 2). Non-selective NSAIDs, such as aspirin, ibuprofen and indomethacin, which also produce gastrointestinal damage, inhibit the aggregation of platelets, decrease kidney function in some patients, and precipitate aspirin-induced asthma (Table 22.1). These drugs inhibit both cyclooxygenase-1 (COX-1) and COX-2 which are central enzymes involved in the synthesis of prostaglandins and related compounds.
The New Frontiers In Pathogenesis And Treatment: Methotrexate And Leflunomide
Authors: Rau Rolf
Published: November 2023

In 1947, aminopterin was synthesized as an antifolate for the treatment of tumors. Four years later, Gubner1 reported the successful treatment of seven patients with rheumatoid arthritis (RA) with aminopterin. Methotrexate (MTX) (amethopterin), synthesized in 1948, proved to be less toxic than aminopterin and more feasible for longer term treatment. However, because of the dramatic effects of corticosteroids in the treatment of RA, few rheumatologists were interested in MTX. The first pilot studies only appeared in the early 1980s, encouraging a systematic evaluation of low-dose MTX treatment in RA.
The Impact Of Physiotherapy
Authors: Moritz Ulrich
Published: November 2023

Decline of function over time is found in most patients with rheumatoid arthritis (RA). About 50% of patients show evidence of articular damage with radiographic joint space narrowing and/or erosions within the first two years of disease . Early retirement, within three years, has been found in 37% of early cases of rheumatoid arthritis . The main functional limitations pertain to pain, decreased joint motion, muscle weakness, reduced endurance, and limitations in aerobic capacity. The unpredictable course of the disease often causes anxiety and depression, and reduces self-efficacy. Physiotherapy is an essential part of comprehensive management for patients with rheumatoid arthritis, and there is a growing body of knowledge concerning the efficacy of physiotherapeutic interventions . Most recent research on physiotherapy has focused on exercise therapy.
Patient Education
Authors: Lindroth Ylva
Published: November 2023

Patient education has been defined as ‘a planned learning experience using a combination of methods such as teaching, counseling, and behavior modification techniques which influence patients’ knowledge and health behavior . . .[and which] involves an interactive process which assists patients to participate actively in their health care, and provides them with information about available health service and their use’ . It should be distinguished from primary prevention strategies such as health education and health promotion programs. The latter may be of importance for some forms of arthritis, for example osteoarthritis (weight reduction in obesity) or osteoporosis (increase in calcium intake and physical activity). For patients with chronic disease, the goal of patient education is to minimize the consequences of the disease and maximize the capacity of the individual to enjoy a high quality of life . Even as recently as 1976, the importance of educating arthritis patients was neither acknowledged in medical textbooks, nor mentioned in printed matter on arthritis written expressly for patients .
Health Economics
Authors: Callahan Leigh F
Published: November 2023

Arthritis and other rheumatic conditions are highly prevalent, a leading cause of disability, and contribute to substantial economic consequences 1–19. These conditions as a whole impose less of an impact in terms of mortality compared to other chronic conditions, but a considerable burden in terms of morbidity and costs. Rheumatoid arthritis (RA), the second most prevalent form of arthritis, is a progressive, systemic, chronic disease affecting 0.5–1% of the population 1,20–22. RA results in significant morbidity and mortality14,23. Morbidity includes functional loss, pain and fatigue, substantial psychological and social effects, work disability, and time loss . There are also significant economic consequences associated with RA for individual patients, their families, and society 12,18,19,25–51.
The Cervical Spine
Authors: Casey T H , Crockard H A
Published: November 2023

Cervical spine involvement characteristically involves the atlantoaxial complex, the most mobile part of the spine, with the radiological abnormalities being classified into those of atlantoaxial subluxation (AAS), which may be horizontal or vertical in direction. Significant subaxial disease is less common and usually coexists with the above deformities (Fig. 36.1). In many cases these radiological abnormalities remain asymptomatic for years, but these patients nonetheless are at continued risk from a range of neurological complications and even sudden death from medullary compression. Despite the predilection that rheumatoid arthritis has for the cervical spine and the severe consequences that may ensue, there has been surprisingly little work in determining the factors that influence which patients will become myelopathic, and if and when they do, what role has surgery to play.
Genitourinary tract infections in cancer patients
Authors: Nambirajan T , ’Sullivan Joe M O
Published: November 2023

Infections of the genitourinary (GU) tract are a relatively uncommon complication of cancer treatment; however, they can be very debilitating and difficult to treat. In patients with cancer, susceptibility to urinary tract infection (UTI) is contributed to by immunodeficiency secondary to underlying disease, damage to the urothelium from the tumour itself, blockage of normal urinary flow by tumour, and most significantly to toxicity from anticancer therapy. There is a relatively wide spectrum of possible infections of the GU tract in this group of patients. A source of difficulty in the diagnosis and treatment of GU syndromes in the cancer patient is that some cancer therapies, in particular pelvic radiotherapy, and certain chemotherapeutic agents, e.g. cyclophosphamide, can mimic the symptoms of bladder infection leading to unnecessary antibiotic therapy. In this chapter we will discuss the spectrum of common pathogens as well as the spectrum of syndromes they cause. This chapter will address some of the common GU infection syndromes that can be complicated by a cancer diagnosis or cancer therapy. The specific management of neutropenic fever and sepsis caused by UTI is discussed in greater detail elsewhere in this text. The clinical syndromes discussed here are pyelonephritis, cystitis, prostatitis, sexually transmitted urethritis, and epididymo-orchitis.
Infections in patients with cancer at the end of life
Authors: McLoughlin Caroline , Watson Max
Published: November 2023

The treatment of patients in the last stages of life has been spotlighted in recent years with debates surrounding euthanasia, physician-assisted suicide, advance directives, and issues relating to ‘do not resuscitate’ orders. The use of antimicrobials in patients with advanced malignancy has become part of this contentious discussion, in which there is a tendency for their true efficacy to be over, or under emphasized in the heat of debate. Thus, managing infection in patients with advanced malignancy requires both clinical skill, as well as wisdom and flexibility to help patients and their families negotiate this very important part of life which, ‘. . . has a significance out of all proportion to its duration’ (Dame Cicely Saunders 1918–2005). This chapter, focusing on patients with cancer at the end of life, attempts to describe the frequency of infection; the associated risk factors; the most common sites; the range of common infectious organisms encountered; the resulting symptoms; the efficacy of antimicrobials and other interventions; and the management of common infections. It concludes with some algorithms for antimicrobial use.
Head (brain) injury rehabilitation team
Authors: Appleton Richard , Furlong Liz , Baldwin Tony
Published: November 2023

Recovery from a brain injury is not like a recovery from any other injury, as the effects are far more complex and pervasive, and affect a whole range of attributes (Medical Disability Society 1988). These changes can range from the subtle and barely noticed, to being significant and very obvious, fundamentally altering the child ‘s emotional, intellectual, and social behaviour. These changes can be observed both in the acute stage, but more typically, these deficits become obvious and remain long past the point in which a total physical recovery has taken place. In some cases, skills have to be retaught and alternative strategies given, and the child ‘s behaviour may need modifying. At the same time, both the child and family need emotional support and reassurance. Given the wide range of problems that can follow an injury, no one professional group will be able to provide all the relevant advice and support, and the emphasis, therefore, falls on a whole range of different professionals at different stages during the recovery process.
Immediate medical and nursing needs
Authors: Furlong Liz , Sellars Julie , Doyle Tamsyn , Appleton Richard
Published: November 2023

The purpose of this chapter is to identify and discuss the more common immediate nursing and medical issues and needs of the brain-injured child (and their family) following the acute resuscitation period and on transfer to the neurorehabilitation ward. The chapter also outlines and discusses the importance of play as an integral component of the rehabilitation process.