Carbon-13 NMR Shift Assignments of Amines and Alkaloids


Book Description

The aim of this book is to gather under one cover most of the data presently available on the carbon-13 nuclear magnetic resonance (cmr) spectra of alkaloids. The term "alkaloids" is used here in a very broad sense to include synthetic analogues of the natural products. Simple model amines are also incorporated since these often supply the basic information required in the assignment of chemical shifts for the more complex compounds. The literature on alkaloid cmr spectroscopy has been covered through 1977, but the collec tion of compounds presented here is illustrative rather than exhaustive. The papers included in the reference list afford further information not only on the cmr assignments of the particular compounds provided here, but also incorporate data on additional related structures. Only a few dimeric indole alkaloids are included since to a large extent their cmr spectra can be corre lated directly with those of their monomeric analogues. The present volume is thus a representative empirical compendium of cmr assignments focusing upon alkaloids and model amines, and is intended to aid cmr research in heterocyclic and alkaloid chemistry. The compounds and data presented in this book are classified and organized according to structural similarity. The purpose of such a presenta tion is to demonstrate the common cmr characteristics of a given structural type, while also facilitating an empirical evaluation of the cmr spectral changes specifically reSUlting from relatively minor variations in oxidation level, substitution, or stereochemistry.










Alkaloids


Book Description

It is refreshing to find a book treating alkaloid analysis with all the latest techniques such as inverse-detected two dimensional NMR, GC/MS, and HPLC associated techniques. There have been many developments in the field of alkaloid analysis since the 1950s, not the least of which are the various powerful spectroscopic methods, which dominate this volume. Included also are the various aspects of tobacco alkaloids and analysis in various situations. The complexities of sampling and analysis in tobacco smoke is explained. Analysis of alkaloids produced by tobacco root cell cultures is included, while genetic and chemical analysis is described for Papaver, a plant of considerable medicinal significance.




The Alkaloids: Chemistry and Physiology


Book Description

The Alkaloids: Chemistry and Physiology




Carbon-13 NMR of Flavonoids


Book Description

This detailed treatise is written for chemists who are not NMR spectroscopists but who wish to use carbon-13 NMR spectroscopy. It shows why measurement of carbon-13 NMR is needed and explains how the method can - or should - be used for rapid characterization of flavonoids, one of the most diverse and widespread groups of natural constituents. The first part of the book presents background information and discussion of the essential aspects of flavonoids and carbon-13 NMR spectroscopy and demonstrates its significant role in the revision of several earlier established chemical structures. It discusses various one- and two-dimensional NMR spectroscopic techniques and other relevant experimental methodologies for the interpretation of spectral details which enable individual resonance lines to be associated with the appropriate carbons in a molecule. The second part provides a comprehensive coverage of the carbon-13 chemical shifts of various classes and subclasses of flavonoids. It also illustrates how to utilize carbon-13 data to gain information for the determination of the nature, number and site of any substituent in flavonoids. Vital information for the differential and complete structure elucidation of the various classes of flavonoids by carbon-13 NMR shielding data is described in-depth in the third part of the book. The book will be welcomed by all those working in natural product chemistry who will appreciate the non-mathematical approach and the fact that such a wealth of theoretical and practical information has been assembled in a single volume.




Alkaloids: Chemical and Biological Perspectives


Book Description

Volume 7 of Alkaloids: Chemical and Biological Perspectives appears under the aegis of a new publisher: the distinguished firm of Springer Verlag New York, Inc. This volume presents three timely reviews on alkaloids: Chapter 1 reviews the homoerythrina and related alkaloids. a group of compounds occurring in seventeen species that are native to countries bordering the western Pacific. Since the last review in 1981, the number of these alkaloids has doubled. Chapter 2 is a comprehensive review of the carbon-13 NMR spectros copy of steroidal alkaloids. Because more than 350 plant species have yielded steroidal alkaloids and these alkaloids exhibit a wide spectrum of biological activities, including teratogenicity, this catalog of spectral and physical data should prove very useful to workers in this field. Chapter 3 presents a detailed review of proton and carbon-I3 NMR shift assignments and physical constants of norditerpenoid alkaloids. This chap ter is an extensive supplement to the review that appeared in Volume 2 of this series. In addition to the catalog of spectral and physical data, this chapter includes tables of proton and carbon shift assignments, a table of the occurrence of alkaloids in plant species, an index of al1 X-ray crystal structure determinations of norditerpenoid alkaloids, and tables containing molecular formulas versus calculated high-resolution mass values and calculated high-resolution mass values versus molecular formulas of nor diterpenoid alkaloids. Each chapter in this volume has been reviewed by an expert in the field. Indexes for both subjects and organisms are provided.







Role of Herbal Medicines


Book Description




Natural Products Chemistry III


Book Description

Natural product chemistry has undergone an explosive growth during the latter half of the current century. This has been brought about by a number of factors. One of these has been the growing number of sub stances from natural sources which display interesting pharmacological activities. These include antibiotics, anti-tumor agents, immunostimu lants, drugs affecting the cardiovascular and central nervous systems, analgesics etc. Another factor has been the improvements made in the technology of isolation processes which includes the development of such techniques as high pressure liquid chromatography which has al lowed the rapid isolation of substances which were previously diffi cult to obtain by classical procedures. The most important factor has been the development of new spectrosopic techniques which have opened up whole new vistas in this exciting field. Prominent in these advan ces has been the advent of powerful superconducting magnets with very stable magnetic fields, and pulse NMR in which the duration, direction and phases of pulses can be accurately controlled by means of mini computers. These have heralded the advent of two-dimensional NMR spec troscopy which has now come to be routinely employed in unravelling complex structures. No less important, though somewhat less dramatic, have been the advances made in the field of mass spectroscopy where new ionization techniques such as positive and negative fast atom bom bardment, field desorption, chemical ionization etc. have allowed the mass spectra of larger non-volatile substances to be recorded. The field of organic synthesis has seen equally rapid advances.