Subject index structure

According to the triazine nomenclature, 5-azauracil is 2,4-dioxo-l,2,3,4-tetrahydro-l,3,5-triazine (2). The subject index of Chemical Abstracts prefers s-triazine-2,4(lH,3H)-dione. Furthermore, some authors use a name derived from the lactim structure, 2,4-dihydroxy-s-triazine (3). The numbering of the substituents is the same for all these types of nomenclature. 

Compounds of the form RN2 X are named by adding the suffix -diazonium to the name of the parent compound RH, the whole being followed by the name of X- (Rule C-931.1, e.g., methanediazonium tetrafluoroborate, benzenediazonium chloride, not phenyldiazonium). Following RC- 82.2.2.3 (IUPAC, 1993), diazonium ions may also be named structurally on the basis of the parent cation diazenylium HNJ, e.g., benzenediazenylium ion. We name the substituent — NJ diazonio (not diazonium) following the same rule. Diazonio describes both mesomeric structures — N = N and — N = N. If one wants to describe one of these structures only, diazyn-l-ium-l-yl or diazen-2-ylium-l-yl has to be used for -N = N or -N = N, respectively. In the General Subject Index of Chemical Abstracts and in Beilstein, diazonium compounds as a class are indexed under this heading. 

Draw the structures of the bicyclo[3.1.0]hex-2-ene-2-carboxaldehyde, cis-jasmone, the Wieland-Miescher ketone and the bis-nor-analogue -which you may find through the "Subject index"- and ... 

CONTENTS List of Contributors. Introduction to the Series An Editor s Forward, Albert Padwa. Preface, Randolph P. Thummel. Cyclooctatetraenes Conformational and ii-Elec-tronic Dynamics Within Polyolefinic [8] Annulene Frameworks, Leo A. Paquette. A Compilation and Analysis of Structural Data of Distorted Bridgehead Olefins and Amides, Timothy G. Lease and Kenneth J. Shea. Nonplanarity and Aromaticity in Polycyclic Benzenoid Hydrocarbons, William C. Herndon and Paul C. Nowak. The Dewar Furan Story, Ronald N. Warrener. Author Index. Subject Index. 

Contents Quantum Mechanics and Atomic Theory. - Simple Molecular Orbital Theory. -Structural Applications of Molecular Orbital Theory. - Electronic Spectra and Magnetic Properties of Inorganic Compounds. - Alternative Methods and Concepts. - Mechanism and Reactivity. - Descriptive Chemistry. - Physical and Spectroscopic Methods. - Appendices. -Subject Index. 

While in volumes 180 and 181 of this series several basic aspects of morphology, inter-phase structure and disorder were addressed, in the present volume, molecular interactions, modeling, phase transformation and crystallization kinetics are considered (see the subject index including keywords from volumes 180 and 181 at the end of the book). Needless to say, in spite of substantial success over 60 years or more we are still far from having a complete and unambiguous picture of polymer crystallization. We firmly believe that a fruitful approach to such a complex problem requires one to give way to many different and sometimes conflicting viewpoints, as we have attempted to do in these volumes. We do hope that they are not only a time-capsule left for... 

G. Herzberg, Molecular Spectra and Molecular Structure. III. Electronic Spectra and Electronic Structure of Polyatomic Molecules, Van Nostrand, New York, 1966. See Subject Index for tables for individual symmetry groups. (In the text of the present article this book is often referred to as Herzberg s Polyatomics.)... 

The second appendix, by Dr. Donald B. Boyd, is an updated compendium of software for molecular modeling, computational chemistry, de novo molecular design, quantitative structure-property relationships, synthesis planning, and other facets of computers helping molecular science. This is one of the most current and most complete compilations anywhere. Appendix 2 provides addresses, telephone numbers, and electronic mailing addresses of suppliers of software. Combined with the subject index of this volume, it is possible to... 

The authors of individual chapters are top specialists in their areas. They comprise an international group of scientists and practitioners (Great Britain, Italy, The Netherlands, Poland, Russia, Sweden, Switzerland, and the U S.A.) from universities and companies that are advanced in the technology of structured catalysts. The editors express their gratitude to all of the contributors for sharing their experience. The editors also appreciate the administrative assistance of Mrs. Qwen Klis and the help of Ms. Annelics van Diepen in the preparation of the subject index. 

Formula indexes are a great help in searching for compounds. If one cannot find a compound in the subject index, he can find it in a formula index, provided he knows its structure. However, even formula indexes depend on rules for arrangement both of the symbols of elements in the formulas and of the completed formulas themselves, and not all indexes are constructed alike. 

Contents Theory of Electrons in Polar Fluids. Metal-Ammonia Solutions The Dilute Region. Metal Solutions in Amines and Ethers. Ultrafast Optical Processes. Metal-Ammonia Solutions Transition Range. The Electronic Structures of Disordered Materials. Concentrated M-NH3 Solutions A Review. Strange Magnetic Behavior and Phase Relations of Metal-Ammonia Compounds. Metallic Vapors. Mobility Studies of Excess Electrons in Nonpolar Hydrocarbons. Optical Absorption Spectrum of the Solvated Electron in Ethers and Binary Liquid Systems. Subject Index. Color Plates. 

From the point of view of importance and chemical feasibility, chloramphenicol (Figure 9) presented an excellent subject for structural modification. It was the first truly broad-spectrum antibiotic isolated, and its structure and total synthesis were both reported two years after the discovery was announced (40, 41, 42). The synthesis of chloramphenicol analogs proved to be one of the great disappointments of early chemical research in the antibiotic field. Hundreds of analogs were synthesized, but none was found superior to the parent drug in terms either of antimicrobial activity or therapeutic index (43). The palmitate and hemisuccinate esters have provided superior dosage forms for oral and parenteral use. One synthetic analog, thiamphenicol (44) has achieved limited use in human and veterinary medicine. 

CASurveyor is a CD-ROM series of more than 1 5 informative summaries of worldwide science literature as published in CA. Each subject-specific topic can be searched using title, author, organization name, patent number, journal, publication year, document type, CA abstract number, keywords, and subject index terms. Abstracts, sequences, and molecular structures are display-able. 

H.-L.Luo Thin-Film Ternary Superconductors. - H.Nohl, W.Klose, O.K Andersen Band Structures of MxMogXg- and M2Mo6X6-Cluster Compounds. - S.D. Bader, S.K.Sinha, B.P.Schweiss, B.Renker Phonons in Ternary Molybdenum Chalcogenide Superconductors. -F.Pobell, D. Rainer, H. Wiihl Electron-Phonon Interaction in Chevrel-Phase Compounds. - Subject Index. 

Contents Introduction. - Preparation, Structural Principles, Properties and Applications. - Isopolyanions. - Heteropolyanions. - Heteropolyanions and Ligands. - Redox Chemistry and Heteropoly Blues. Organic and Organometallic Derivatives. - Polyoxometalate Chemistry. Current Limits and Remaining Challenges. - Appendix Nomenclature of Polyanions. - References. - Subject Index... 

This notion re-emerged as important in a very different context. Look at a well-known printed chemical subject index, and you will note that the number of entries under different headings is very disparate there too. This effect is due to the structure of the subject in question, and to the vocabulary used. It turns out that indexers description of the content of a particular document differs in ways influenced directly by their estimation of the number of postings expected at particular subject headings - and that one might therefore be able to capture decisions made by indexers which would reveal the microstructure of conceptual fields - what today would be called the knowledge structure of the domain. In order to capture these relations it was necessary to compare two entries, and identify variant subject descriptions by first isolating the common parts of the two entries. 

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