bluuebunny/crossref_metadata_2025_split huggingface dataset:
Disorder in the crystal structures of some ‘superflexible’ silahydrocarbons
Authors: Ovchinnikov Yu. E , Struchkov Yu. T 
Published: November 2023

Abstract
The subject of the present paper is the crystal structure and conformation of macrocyclic silahydrocarbons (MS) built of dicarbosilane units -C-SiR -Clinked by single, double or triple carbon-carbon bonds. The first representative of these MS, namely the 4-0 compound (Fig,1; the first digit is the number of Si atoms in the molecule, the second is the number in the series considered; the zero in this case indicates the structure solved by other authors), was structurally characterized in 1986 (Eliassen e,a. 1986), At the same time the crystal structure of another analogous macrocycle 6-1 with six silicon atoms was determined in our laboratory (Voronkov e.a. 1987).
Whither organic crystallography?
Authors: Jones D W 
Published: November 2023

Abstract
The careful measurement and reporting of crystal data -for example in the early volumes of Z.Krist -predates even the discovery of X-rays, let alone that of X-ray diffraction. Subsequently, crystallography has developed into a much broader discipline of structural science, based primarily on diffraction measurements but interacting significantly with other experimental techniques. If there is a crisis in organic crystallography, then it is arguable that this may have been with us for the last quarter of a century. During this time, the combination of automated data collection, direct structure-solving routines, and high-speed computing has progressively reduced the labour and difficulty of the structure elucidation of many “straightforward” crystals, such that many analyses, adequate for the purpose of structure confirmation, have been carried out by inexperienced or novice crystallographers.
Titanocene and zirconocene η-π complexes
Authors: Whitby Richard J 
Published: November 2023

Abstract
Titanium and zirconium are Group 4 transition metals. Both are compara tively cheap and non-toxic and as a result stoichiometric applications are practical. The +4 oxidation state is most common, with the +2 oxidation state being important in many reactions. Titanium also has an extensive chemistry in the +3 oxidation state. The high oxidation state makes the +4 complexes strong Lewis acids, a property which has been widely used in synthesis.
Classic matrix experiments
Authors: Dunkin Ian R 
Published: November 2023

Abstract
Anyone embarking on matrix-isolation studies will want to get on with their own ideas and experiments as soon as possible. There will be little incentive to spend time repeating the work of others. Nevertheless, it is valuable to gain confidence in new equipment or new techniques with some proven examples; so this chapter brings together a selection of matrix experiments from the literature, which can be carried out as tests or simply for fun. The author has carried out a good proportion of the experiments, but by no means all.
Introduction
Authors: Stone A J 
Published: November 2023

Abstract
The idea that matter is made up of atoms and molecules was known to the Greeks, though the evidence for it did not become persuasive until the eighteenth and nineteenth centuries, when the ideal gas laws, the kinetic theory of gases, Faraday’s laws of electrolysis, the stoichiometry of most chemical reactions, and a variety of other indications combined to decide the matter beyond doubt. In the twentieth century, further techniques such as X-ray diffraction and, more recently, high-resolution microscopy, have provided more evidence.
Molecules In Electrostatic Fields
Authors: Stone A J 
Published: November 2023

Abstract
Of the contributions to the interaction energy listed in Table 1.2, the electrostatic interaction is often the most important, as we shall see in later chapters. However all of the contributions to the interaction energy between molecules, except for the unimportant magnetic terms, derive ultimately from the Coulombic interactions between their particles. In order to develop the theory of all these effects, we need to be able to describe the way in which the charge is distributed in a molecule. For most purposes, this is done most simply and compactly by specifying its multipole moments, and while this description has its limitations it provides an essential part of the language that we use to discuss intermolecular forces.
Oxford and ‘big science’
Authors: Merricks Linda 
Published: November 2023

Abstract
Soddy spent almost the whole of the inter-war period at Oxford. He was appointed the Dr Lee’s Professor of Chemistry at Oxford in 1919, a post he held until he retired in 1936. With some reservations, in marked contrast to his years in Scotland, this could be described as a time of almost complete professional unhappiness. Just as his pre-First-World-War years were highly productive, during the inter-war period his scientific work was almost non-existent. However, it was a period in which political and economic work became more and more important to him. For these reasons the inter-war period may be conveniently, if rather artificially, divided into the more or less scientific and the more clearly political areas. Soddy himself would never have recognised this distinction—he always saw himself as a scientist whose science led him to a consideration of matters affecting the functioning of the wider society. However, for clarity, the areas of interest in his life during these decades will be considered in three chapters, the first looking at science, the second at his work on monetary theory in the 1920s and the third at his political involvement in the 1930s.
New Britain
Authors: Merricks Linda 
Published: November 2023

Abstract
To understand Soddy’s development during the next few years, we need to look at the New Britain Group, later known as the New Europe Group. This organization is now relatively unknown but, during the nineteen thirties, it gained a considerable following proposing reforms based on a tripartite programmer of cultural, economic and parliamentary changes which was developed through the period. The economic changes were closely based on Soddy’ s proposals and he was to become an influential member of the group. However, to understand the group during the thirties it is necessary to go back in time to the foundation of the group in inter-war London. This cultural world was characterized by numerous societies, clubs and associations, almost as many as there were individuals involved. Many of these groups had no formal membership, meeting place or publication, most of them were short-lived, while their agendas and programmers varied from merely eating and drinking to saving the whole world. Those who belonged to this world tended to associate with a range of organizations, passing from one to another according to what now look like whims, fancies and fashion. The favored description for these organizations was ‘ group ’ and this will be adopted as the most suitably loose designation. Most of them were geographically near each other, in London and generally near or in Bloomsbury. Even the original ‘Bloomsberries’, although by the late 1920s having their centers in Sussex and France, maintained close links with this area, and with the other, newer groups. The attraction of this part of London was due in part to historical accident—it had long been associated with an intellectual society, and this had led to or depended on the number of cafes, tearooms, restaurants and pubs where informal meetings and conversations could be held. The nearby houses were also still cheap and large enough to provide suitable premises for lecture rooms and offices.
The darkest days
Authors: Merricks Linda 
Published: November 2023

Abstract
The period of Soddy’s life from 1935 until after the Second World War was cryptically summed up in his obituary in The Times,‘Then after 1936, there was silence ... ‘ While not strictly accurate, this points to a problem in any attempt at a complete biography of Soddy. After 1936 he almost disappeared from the various areas so far discussed—science, monetary theories and New Britain—and, with some minor exceptions, the silence lasted until the late 1940s. Finally, there is almost no evidence for his activities during the whole of the Second World War. Unlike the other chapters of his life, the explanation for this is quite straightforward. The decade from 1935 was the worst of Soddy’s life. It was the period during which his professional life ended, his hopes for peace and prosperity were shattered and his worst fears about the implications of his atomic discoveries were realized. Perhaps worst of all, however, his personal happiness was destroyed when his wife, Winifred, died. She became ill in 1935 and then died on 17 August 1936. This marked the end of a remarkably contented twenty years of marriage. As his friend Sir John Russell wrote in 1956, ‘The death of his wife ... was a blow from which he never fully recovered’.
The post-war world
Authors: Merricks Linda 
Published: November 2023

Abstract
The end of the Second World War, as we have seen, left intact little of what Soddy had fought for in the inter-war period. The virtual disintegration of the New Europe Group and the manifest failure of monetary reform to influence the post-war Labour Government seems to mark the beginning of a period of defeat. However, two different areas of interest and concern changed this. Firstly, and vitally, he rediscovered a positive commitment to science, and to atomic science in particular. Secondly, he returned to his love of travel. The rediscovery of these areas was sparked by two remarkable women, both noted for their determination in following through their plans, but one far more successful than the other. Other than occupying aspects of Soddy’s life at the same time, there is no connection between these two, and so although they both need to be considered for the effect they each had on him, they will be dealt with separately. When Soddy met her in the late forties, Margaret Tatton had been running some part of the Le Play Society from the mid-twenties, and while she had shown her efficiency in organizing their tours, her methods of doing so had not always been popular. One member of the group wrote, ‘Beware the Tat whose gentle voice/ All will obey—they have no choice/ The velvet glove will quite conceal/ The clutching hand with grip of steel.’ Muriel Howorth was just as determined to achieve her ends, but less successful in fulfilling them. She had developed an interest in atomic science and attempted to create an organization within which non-scientists could learn about its potential, but this, for reasons discussed below, was never very successful, and was short-lived. She involved Soddy in this and also decided to write his biography.
Introduction
Authors: Ghiron Chiara , Thomas Russell J 
Published: November 2023

Abstract
The exercises in this book are intended to provide challenges for people with various levels of experience. A final year undergraduate student should obviously not be expected to tackle a problem without the aid of his or her favourite textbooks, and will still undoubtedly have difficulty with the more advanced problems. The advanced aspects of an exercise are intended for a more experienced chemist to analyse and discuss in detail. A student will hopefully find that in studying the exercises, while at first it will be difficult to complete even half of the questions unaided, with time both the size of his or her ‘vocabulary’ of reactions and the time necessary to study an exercise will change dramatically.
Total Synthesis of Islandic Acid I Methyl Ester
Authors: Shimizu T , Hiranuma S , Watanabe T , Kirihara, M 
Published: November 2023

Abstract
Discussion Points The sequence from 2 to 3 introduces a tetrahydropyranyl (THP) group. What is the mechanism of this step? Following step d a quantity of compound 9 was isolable. Suggest a mechanism for its formation.Give two alternative methods of removing a SEM group as in step.
Total Synthesis of (+)-Patulolide C
Authors: Takano S , Murakami T , Samizu K , Ogasawara, K 
Published: November 2023

Abstract
Discussion Points What is the mechanism of steps b and k? Give a method for the formation of the Z-olefin 14 from alkyne 9. Further Reading A similar approach to that described above was used by the authors in the synthesis of a milbemycin K fragment, see: S. Takano, Y. Sekiguchi and K. Ogasawara, Heterocycles,1994, 38,59. For an excellent review on the two-directional chain synthesis strategy see: C. S. Poss and S. L. Schreiber, Acc. Chem. Res.,1994, 27, 9. Another elegant application of this strategy to the synthesis of (-)-parviflorin has recently been published: T. R. Hoye and Z. Ye, J. Am. Chem. Soc.,1996, 118,1801. For a review of macrocyclic ring formation methods see: Q. C. Meng and M. Hesse in Top. Curr. Chem.,1992, 161,107. A more recent chemoenzymatic synthesis of the related (R)-patulolide A has also been published: A. Sharma, S. Sankaranarayanan and S. Chattopadhyay, J. Org. Chem.,1996, 61,1814.
Asymmetric Synthesis of the Milbemycin β3 Spiroketal Subunit
Authors: Holoboski M A , Koft, E 
Published: November 2023

Abstract
Discussion Points Suggest a method of detennining the enantiomeric excess of the product obtained in step f. What governs the regioselectivity of step f? Propose a structure for the product of step h and the driving force behind its conversion into compound 7. Based on mechanistic considerations and the fact that it displays only two 1H NMR signals between 6.0 ppm and 4.5 ppm, suggest a structure for the product of step m. What is the mechanism of step p? What governs the stereochemistry of the spiroketal centre? Further Reading For a review of approaches to the synthesis of avennectins and milbemycins see: T. A. Blizzard, Org. Prep. Proced. Int.,1994, 26,617. For a recent total synthesis of milbemycin G see: S. Bailey, A. Teerawutgulrag and E. J. Thomas, J. Chem. Soc. Chem. Commun.,1995, 2519 and2521. For the synthesis of the spiroacetal fragment of milbemycin 1 see: S. Naito, M. Kobayashi and A. Saito, Heterocycles,1995, 41,2027. For an excellent introduction to hydroboration see S. E. Thomas, Organic Synthesis- The Roles of Boron and Silicon,Oxford University Press, Oxford, 1991, pp.1-8. A more detailed description can be found in: A. Pelter, K. Smith and H. C. Brown, Borane Reagents,Academic Press 1988, pp.165-230. For another application of a Birch reduction-ozonolysis sequence see: G. Zvilchovsky and V. Gury, J. Chem. Soc. Perkin Trans. 1,1995, 2509. For structural details of more recently isolated milbemycins see: G. H. Baker, S. E. Blanchflower, R. J. Dorgan, J. R. Everett, B. R. Manger, C. R. Reading, S. A. Readshaw and P. Shelley. J. Antibiot.,1996, 49, 272.
An Approach to Zoanthamine Alkaloids
Authors: Tanner D , Andersson P G , Tedenborg L , Somfai, P 
Published: November 2023

Abstract
Discussion Points What was the stereochemical outcome of the reduction step h? Propose a mechanism to explain the formation and stereochemistry of compound 7. What is the structure of the intermediate 6 formed prior to the rearrangement? Further Reading For a recent review of asymmetric and enantioselective epoxidations see: E. Hoeft, Topp. Curr. Chem.,1993, 63. For the application of the Johnson orthoester Claisen rearrangement to a similar system see: A. Srikrishna and R. Viswajanani, Tetrahedron Lett.,1996, 37,2863.
The Synthesis of (±)-12a-Deoxytetracycline
Authors: Stork G , Clair J J La , Spargo P , Nargund R P , Totah, N 
Published: November 2023

Abstract
Discussion Points What is the purpose of the Diels-Alder cycloaddition step a? Give an explanation for the selectivity in the addition of the Grignard reagent in step b. How is it dependent on the number of equivalents of methyl magnesium bromide employed? What is the mechanism of step e? What governs the stereoselectivity of the addition of the anion of isoxazole 9 to compound 8? Further Reading For a review on recent advances in the field of tetracycline antibiotics see: V. J. Lee, Expert Opin. Ther. Pat.,1995, 5, 787. For a review on the mechanism of bacterial resistance to tetracycline antibiotics see: D. E. Taylor and A. Chau, Antimicrob. Agents Chemother.,1996, 40,1.
Synthesis of the Tricarbonyl Subunit C8-Cl9 of RapamycinB
Authors: White J D , Jeffrey, S C 
Published: November 2023

Abstract
Discussion Points Explain the selectivity observed in the Wittig olefination step j and suggest a reason why it was necessary to protect the hydroxyl group in 8. What is the purpose of boron trifluoride etherate in step p? Explain the use of cerium trichloride in step s? Give a mechanism for the Chan rearrangement b’? What intermediate is presumably formed in the m-CPBA induced rearrangement of step c’? Further Reading For studies on 1,2-anionic rearrangements in the gas phase, see: P. C. H. Eichinger, R. N. Hayes and J. H. Bowie, J. Am. Chem. Soc.,1991, 113,1949. For a review on the stereochemistry and mechanism of the Wittig reaction, see: E. Vedejs and M. J. Peterson, Topics in Stereochemistry,1994, 21,1. For studies on the Dess-Martin periodinane, see: D. B. Dess and J.C. Martin, J. Am. Chem. Soc.,1991, 113,7277; S. D. Meyer and S. L. Schreiber, J. Org. Chem.,1994, 59,7549. For some references on the Rubottom oxidation, see: J. Jauch, Tetrahedron,1994, 50,1203; R. Gleiter, M. Staib and U. Ackermarm, Liebigs Arm.,1995, 9,1655. For studies on the presence of water in the CeCl3/RLi system, see: W. J. Evans, J. D. Feldman and J. W. Ziller, J. Am. Chem. Soc.,1996, 118,4581.
Total Synthesis of (–)-Chlorothricolide
Authors: Roush W R , Sciotti, R J 
Published: November 2023

Abstract
Discussion Points Propose suitable methods for the synthesis of optically active alcohol 1 from its corresponding ketone. Suggest a mechanism for the iodination of compound 2. What is the purpose of the DIBAL-H in the sequence? Give the mechanism of step f. Explain the stereoselectivity of steps g and i. What is the structure of 7 introduced in step j? Rationalise both the mechanism and stereocontrol that led to the cyclic system 8, the major product of step j. What is the purpose of the 2-methyl-2-butene used in step r?
Synthesis of (+)-Ceratopicanol
Authors: Clive D L J , Magnuson S R , Manning H W , Mayhew, D L 
Published: November 2023

Abstract
Discussion Points What directs the selectivity of the reduction step a? What is the reagent usually employed for the reduction of less hindered cx,(3-unsaturated ketones? What is the mechanism of step e? In step g a Ph3P-CBq system is used after reducing the aldehyde 5. What is the mechanism by which this system works? Had it been necessary to form a six-membered ring in step k, is it likely that the method used in this synthesis would have been sucessful? Step k proceeds via the ring-opening of the epoxide 8. Suggest a reason for its regioselectivity, evident from the fact that the product formed is 11. The overall transformation of compound 13 into 15 employs a classical deoxygenation protocol. Suggest other ways of deoxygenating alcohols or ketones.
81. Total Synthesis of (–)-Grayanotoxin III
Authors: Kan T , Hosokawa S , Nara S , Oikawa M , Ito S , Matsuda F , Shirahama H 
Published: November 2023

Abstract
Discussion Points Propose a mechanism for the sequence carried out in steps c and d. The epoxidation of compound 19 is highly stereoselective. What is likely to be the major factor in controlling this process? Give an alternative method of generating a 1,2-diol from two carbonyl groups as carried out in step i’.
Primary producers on the shore: the autotrophs
Authors: Little Colin , Williams Gray A , Trowbridge Cynthia D 
Published: November 2023

Abstract
Carpeting rocky shores around the world are macroscopic seaweeds, tiny unicellular microalgae and cyanobacteria, and in some places seagrasses. Very oJen there are also lichens high on the shore, while a variety of angiosperms (Kowering plants) fringes the upper shore levels. All these organisms are photosynthetic autotrophs: essentially the plants of the sea that capture CO2 gas and convert it into sugar, using light energy from the sun. Autotrophs form the base of the food web in most communities, including wave-swept rocky shores and sheltered rocky platforms, and also provide a habitat for many other organisms.
The functioning of rocky-shore communities
Authors: Little Colin , Williams Gray A , Trowbridge Cynthia D 
Published: November 2023

Abstract
The functioning of rocky-shore communities is not determined solely by events that take place on the shore. As we have emphasized throughout this book, rocky shores are not isolated areas of land delimited by the rise and fall of the tides, but rather joined by the continuous movements of the ocean’s waters. Large-scale oceanic patterns will determine the energy and nutrient supplies to the intertidal area, as well as the supply of species propagules that may settle on the shore. The diversity of organisms and the energy and nutrients that drive the interactions on shores are, therefore, initially determined by geographic locality.
One way of understanding the functioning of rocky-shore ecosystems is to examine their trophic organization, since this identiIes the function of various species within the community. Starting with this approach, we then consider the various questions this raises.
A to Z of Thermodynamics
Authors: Perrot Pierre 
Published: November 2023

Abstract
The title is a perfect description. Arranged alphabetically this book explains the words and phrases that crop up in thermodynamics. The author does this without resorting to pages of mathematics and algebra: the author's main aim is to explain and clarify the jargon and concepts. Thermodynamics is often difficult and confusing for students. The author knows this after 20 years of teaching and does something about it with this dictionary.
Comparison of a Pharmacy-Based Observational Study With GCP-Conform Clinical Studies With Effervescent Acetylsalicylic Acid in Migraine
Authors: Petersen-Braun M , Weingartner U , Gessner U , Göbel H 
Published: November 2023

Abstract
Approximately half of the patients suffering from migraine headache treat themselves by using OTC drugs. Despite the common usage of acetylsalicylic acid (ASA) for self- treatment of acute migraine attacks, data about the usage, efficacy, and safety under real-life conditions in self-medication are lacking. Data about the drug use in self- medication under the terms of the patients’ management in everyday life can only be derived directly from the patients.
Diagnostic Criteria For Primary Headaches of ICHD 2nd Edition 2004*
Authors: Pedini M , Alberti A , Mazzotta G , Sarchielli P 
Published: November 2023

Abstract
The first version of the software, based on the diagnostic criteria of the IHS classification for primary headaches 1988, was developed in 2000 to evaluate the applicability of the diagnostic criteria by specialized headache centers. The analysis of over 500 clinical charts from nine Italian headache centers always gave unambiguous diagnoses. But for various reasons, a concordance between the clinical diagnosis and that derived from the software was found only in 69% of the cases, in which the u error for the total number of charts analyzed did not exceed 2.2%.
Prevalence, Clinical Characteristics, and Medication of Migraine in Latin America: a Population-Based survey
Authors: Morillo E , Sanin L C , Alarcón F , Aranaga N , Aulet S , Chapman E , Conterno L , Estévez E , Garcia-Pedroza F , Garrido J , Leston J , Macias-Islas M , Monzillo P , Núñez L , Perez A , Plascencia N , Rodrguez C , Silva F , Simonovis N , Takeuchi Y , Hettiarachchi J 
Published: November 2023

Abstract
Migraine is a common disease worldwide, ranked among the 20 leading causes of disability by the World Health Organization. Although the prevalence of migraine varies among surveyed populations, the prevalence in Latin America has not been established by large-scale population studies. Also, the symptoms and disability associated with migraine, as well as the pattern of medication use by migraineurs, have not been well-documented in Latin American regions.