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.

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 Alkaloids: Chemistry and Pharmacology

The alkaloids were of great importance to mankind for centuries, long before they were recognized . as a chemical class. The influence they have had on literature is hinted at by some of the quotations I have used as chapter headings. Their influence on folklore and on medicine has been even greater. The scientific study of alkaloids may be said to have begun with the isolation of morphine by Sertiirner in 1804. Since that time they have remained of great interest to chemists, and now in any month there appear dozens of publications dealing with the isolation of new alkaloids or the determination of the structures of previously known ones. The area of alkaloid biochemistry, in comparison, has received little attention and today is much less developed. There is a certain amount of personal arbitrariness in defining "bio chemistry", as there is in defining "alkaloid", and this arbitrariness is doubtless compounded by the combination. Nevertheless, it seems to me that in any consideration of the biochemistry of a group of compounds three aspects are always worthy of attention-pathways of biosynthesis, function or activity, and pathways of degradation. For the alkaloids, treatment of these three aspects is necessarily lopsided. Much has been learned about routes of biosynthesis, but information on the other aspects is very scanty. It would be possible to enter into some speculation regarding the biosynthesis of all the more than 4,000 known alkaloids.

The Alkaloids: Chemistry and Physiology