The Isoquinoline Alkaloids

The Isoquinoline Alkaloids: A Course in Organic Chemistry is a description of the chemical structures of alkaloids. The book discusses the processes for degradation of isoquinoline alkaloids to recognizable compounds such as oxidation and exhaustive methylation. The associated processes in removing the nitrogen atom are also explained. The commonly used Hofmann process and the interpretation of its result are evaluated in the degradation of alkaloids. The cactus ""pellote"" used by Mexican Indians to induce hallucinatory experiences is examined. The active ingredient is identified as mescaline; its composition is analyzed to contain one primary amino and three methoxyl groups. The different syntheses made to duplicate mescaline are described. The structures of morphine, codeine, and thebain, which are all alkaloids of opium, are also analyzed. Another example of a principal alkaloid found in a plant is emetine found in the root of the ipecac. The pharmacological bases of emetine are isolated and noted as emetamine, cephaeline, psychotrine, and O-methylpsychotrine. The text also traces many other structural relationships within the subgroups of the isoquinoline alkaloids. Chemists, students and professors in organic chemistry, and laboratory technicians whose work is related to pharmacology will find this book informative.

Isoquinolines form one of the largest groups of plant alkaloids and they in clude a number of valuable clinical agents such as codeine, morphine, eme tine and tubocurarine. Research into different aspects of isoquinolines con tinues in profusion, attracting the talents of botanists, chemists, bioche mists, analysts, pharmacists and pharmacologists. Many of these aspects are of an interdisciplinary nature, and in April 1984, The Phytochemical Society of Europe arranged a 3-day symposium on The Chemistry and Bi ology of Isoquinoline Alkaloids in order to provide a forum for scientists of differing disciplines who are united by a common interest in this one class of natural product. Each chapter in this volume is based on a lecture given at this symposium. Attempts have been made to make the aims and objectives, experimental findings and conclusions reached, intelligible to scientists of differing backgrounds. The introductory chapter, which is mainly based on a historical discus sion, stresses that plants containing isoquinolines have proved to be both a boon and a curse to mankind. The Opium Poppy, Papaver somniferum, produces the medicinally used alkaloids morphine, codeine, noscapine and papaverine whilst it also continues to provide drugs of abuse, particularly morphine and its readily prepared O,O-diacetyl derivative, heroin. Numer ous other alkaloids have been isolated from other members of the Papaver acea, and a knowledge of their presence and distribution within the various species has proved a useful adjunct to systematic botanical studies.

The Isoquinoline Alkaloids: Chemistry and Pharmacology presents an overview of the chemistry, biogenesis, spectroscopy, and pharmacology of the isoquinoline alkaloids. This book examines the significant and interesting aspects of alkaloids. Organized into 32 chapters, this book starts with a discussion of the biogenesis of the isoquinolines and the various pharmacological effects of simple tetrahydroisoquinolines that have stimulant and convulsive properties. This text then explores the infrared absorptions, with emphasis on wavelength and frequency. Other chapters include topics on synthesis, degradation, reactions, absolute configuration, as well as on ultraviolet and nuclear magnetic resonance spectroscopy. This book further explores the various methods available for the preparation of simple tetrahydroisoquinolines, including the Bischler–Napieralski, Pictet–Spengler, and phenolic cyclization, as well as the Friedel–Crafts acylation. The last chapter deals with ancistrocladine, which is the first isoquinoline alkaloid found to possess a methyl group. Biochemists and biophysicists will find this book useful.

Plant classifications are based on morphological characters and it is difficult, particularly in small plants and grasses, to identify these below generic level on the basis of these characters using a dissecting microscope. Plant species have intra- and inter-specific variation in secondary metabolites which can be utilized as marker compounds for identification and classification of plants. Secondary metabolites are produced as a result of primary metabolism and the production of these compounds not only involves several genes but also it is an energy dependent process. Hence these products cannot be considered as insignificant for the plant and the environment. Modern tools of molecular biology and secondary metabolites present in them can definitively decide about classification of plants. Absence of correct identification of plant is associated to many problems of resource utilization. Due to wide availability of these tools, interest has revived in systematics and correct classification of plants based on these parameters for their sustainable utilization and resource management. The purpose of this book is to assess the potential of phytochemical and molecular tools in the systematic and classification of plants. The topics covered include species concept, barcoding and phylogenetic analysis, chemotaxonomy use of polyketides, carotenes, cuticular wax, volatile oils, biodiversity of corals, metazoans, Ruta and Echinocereus. It provides comprehensive and broad subject-based reviews, useful for students, teachers, researchers, and all others interested in the field. The field has been kept wide and general to accommodate the wide-ranging topics. This book will be useful to agriculturists, chemists, botanists, industrialists, and those involved in planning of crop plants.

Substantial advances in the realm of isoquinoline alkaloids have occurred since The Isoquinoline Alkaloids, Chemistry and Pharmacology, was published in 1972. The present volume represents an effort to describe important developments since that time. The organization of the present book is essentially the same as in The Isoquinoline Alkaloids. Each chapter begins with a discussion of structural elucidation and synthesis, a description of typical reactions then follows, and the chapter ends with coverage of biogenesis, pharmacology, and spectroscopy. New chapters have had to be added to describe the completely new alkaloidal types discovered since 1972. These include baluchistanamine (an isoquinolone benzylisoquinoline dimer), the aporphine-pavine dimers, the 4,5-dioxoapor phines, the secoberbines, the 3-arylisoquinolines, eupolauridine, and very recently imerubrine. Another new chapter discusses the chemistry of the aristolo chic acids and aristolactams, a group of substituted phenanthrenes, obviously of isoquinoline derivation in spite of the fact that they do not incorporate a basic nitrogen function. The aristolochic acids and aristolactams were not in cluded in The Isoquinoline Alkaloids even though they were known at the time that book was written. On the other hand, one group of alkaloids which was included in The Isoquinoline Alkaloids and nevertheless was deemed not to belong properly in the present work is the naphthalenoisoquinolines, which include ancistro cladine and its relatives. These bases do not originate biogenetically· from tyrosine, and beside incorporating tetrahydroisoquinoline moieties show no clear structural relationship to the more orthodox isoquinoline alkaloids.