except from Ths simple plant isoquinolines(Shulgin, Alexander)- The passion of my life over the last forty years has been a compelling interest in psychedelic drugs. They have given me not only an exciting area of research and discovery, but also a personal understanding of just who I am and why I am. Certainly these guides and sacraments will eventually play an accepted role in our community and in our culture. Almost all of these drugs have either been isolated from psychoactive plants, or are the results of subtle variations of the molecular structures of these isolates. I have always looked at these plants and the compounds they contain in the same way that the Romans dreamt of their ultimate empire. It was Caesar who acknowledged that all of Gaul was divided into three parts and to understand it, to conquer it, each part had to be respected as a separate entity. It is exactly the same way with understanding the world of psychedelic drugs. There are three domains of inquiry that must be studied independently before one can begin to appreciate just how they might integrate into a single concept. These three are now, I believe, coming together. One part is the large collection of psychoactive compounds known as the phenethylamines. The first known plant psychedelic was mescaline, or 3,4,5-trimethoxyphenethylamine. This simple one-ring alkaloid was discovered in the North American dumpling cactus Peyote (Anhalonium toilliamsii) in the late nineteenth century, and is now known to be a component of over fifty other cacti. Over a dozen other cactus phenethylamines have been isolated and identified, and there are perhaps a hundred synthetic analogues that are now also known to be psychedelic in action. This body of information has been published by my wife Ann and me as a book entitled "PIHKAL: A Chemical Love Story." PIHKAL stands for Phenethylamines I Have Known and Loved. An almost-as-large chemical group contains the tryptamines. N,NDimethyltryptamine (DMT), its 5-hydroxy analogue (bufotenine) and the O-methyl ether homologue 5-methoxy-N,N-dimethyltryptamine (5- MeO-DMT) are widely distributed in the world of natural plants. There are also the well-established mushroom alkaloids 4-phosphoryloxy-N,N- vii dimethyltryptamine (psilocybin, and the dephosphorylated indolol psilocin)and the mono- and didemethylated homologues baeocysteine and norbaeocysteine. These seven natural alkaloids have provided the template for perhaps two dozen analogue structures that are now well-established psychedelic agents. Ann and I have written a companion volume to PIHKAL called "TIHKAL: The Continuation" (TIHKAL stands for Tryptamines I have Known and Loved), which has brought together most of these natural and synthetic tryptamines into a single reference site. The remaining third of the above Gallic synthesis deals with what I had originally called the "Q" compounds, as distinguished from the "P" compounds and the "T" compounds (the phenethylamines and the tryptamines). The actual parent structural element is the isoquinoline ring system,and my initial plan was to give this third book a name similar to the first two. IIHKAL wouldn't do it, but QIHKAL shows a good bit of class, at least in my opinion. Or maybe THIQIHKAL because most of them are really tetrahydroisoquinolines. Well, all these names are now on hold, as Ann is uncomfortable with them. No name has yet been decided upon, but ideas such as The Third Book, or Book Three, are under consideration. Names like these resound with a rather striking arrogance, if nothing else. To understand the relationship of the isoquinolines to the phenethylamines and the tryptamines, the concept of ring closure must be used. This is a sort of synthetic scorpion sting at the molecular level. A tryptamine has an indole ring as its centerpiece and from it there extends a floppy two-carbon chain terminated by an amino nitrogen atom. A small but very important family of plant alkaloids is the product of this amine exploiting a carbon atom from somewhere, and making a new six-membered ringby that "sting" reaction back onto the parent indole ring. This family has the name,~-carbolines, and the formed compound is 1,2,3,4-tetrahydro- [3-carboline. QCNH N I H tryptamine 1,2,3,4-tetrahydro-~-carboline.
A phenethylamine has a benzene ring as its centerpiece and it, too, has a floppy two-carbon chain extending out from it and also terminating in an amino group. In a reaction that is exactly analogous to that of the tryptamines,this amine can pick up a carbon atom and bend back to react viii with the parent benzene ring forming a six-member ring. This is the origin of the isoquinoline family of natural products, and the formed compound is l,2,3,4-tetrahydroisoquinoline. phenethylamine 1,2,3,4-tetrahydroisoquinoline As mentioned above, this third part of the plant psychedelic alkaloid world involves tetrahydroisoquinolines and is the substance of our third book. A very reasonable appendix to be written for this book would be a search of the chemical literature for the known isoquinolines that might be of interest as pharmacological agents. There are certainly many plant products, as well as a monster inventory of synthetics, some of which are made based on plant examples, but many others are simply laboratory creations of the imaginative chemist. It was soon apparent that this compilation would become unmanageably large. The first major trimming was the elimination of the compounds that were synthetic, and the limitation of the listing to those compounds that have been reported as plant products. These isoquinolines could play the dual role of serving not only as potential contributors to the action of psychoactive plants but also as prototypes for the synthesis of new materials that might themselves be biologically active. But even this restriction to only plant compounds was not sufficiently severe. There seemed to be no end to existing isoquinoline treasures. As I wandered deeper into the literature, I kept finding an ever-increasing inventory of research papers that described fantastic stuff. As a totally make-believe example, pretend that there was a compound named Dogabinine that has only been found in the Dogabic tree in the Twathtu rainforest, which the natives say cures leprosy, and which has a complex chemical structure that just happens to carry an isoquinoline ring in its lower southwest corner. To include all such monsters would make the appendix many thousands or even tens of thousands of pages long. And if you were to add into this compilation all the known derivatives, extensions and chemical modifications of Dogabinine, then you would have a review entity that would be several volumes in length. Ifsuch a collection were to exist, I would have it in my library right now. Butit does not exist and it may never exist. IX Some middle ground, some rational compromise, had to be found. I wanted this collection to present all isoquinolines that are known to be plant alkaloids, but respecting carefully defined restrictions that exclude horror monsters such as Dogabinine. The final compromise was to establish separate entries for all the known two-ring isoquinolines that are from natural sources, including those that carry a third ring as a substituent (suchas a benzyl group) at the I-position. And within each of these entries,there are included all natural alkaloids that can be seen as products ofa hypothetical attack of an ortho hydrogen of this substituent on some other position of the isoquinoline nucleus. This "ortho-X attack" is exactly defined and illustrated in the Foreword tha t follows. All plant sources are recorded (or representative sources if there are too many) and literature citations are also included in each entry. But even with these restrictions, this "appendix" to a third book was becoming larger and larger, and it soon became apparent that it was totally inappropriate. There would be far too many pages for a minor appendix in a book that is to be dedicated to cactus and isoquinolines. And by the time my stream-of-consciousness commentary was added in the textwhere I felt it should be added, the mass increased to the extent that it had to be a reference book in its own right. Voila.Let's try to get all that information together into a single modest package and make it available to the chemists and botanists who might wantit. Should it be a review article in Chemical Reviews or the Journal of Natural Products? Several factors said "No." Most botanical review surveys are not searchable except by taxon name (that would assume that you would know the plant from which it came) or by some complex and maddening Chemical Abstracts entry that dealt with some alphabetization that demanded the knowledge of the structure and the way the structure would be listed. And most review articles also insist on a tidy forma t that is without editorial comment and does not contain volunteered ideas and extrapolations. An obvious solution became apparent. Create a single reference book to contain all this information. Use the chemical substituents as an alphabet. Visually travel around the structural image of the molecule in a logical direction, address the substituent groups in some logical way which will be called alphabetical, and progress until you find the target you are searching for, or until you find an empty hole where it would have been had it been known. So this book has come into existence simply to meet this need, and to relieve the potential "Third Book" readership of a killer of an appendix. the substituents and, especially, the connection between simple benzylated isoquinolines and the nature of the cyclized products of ortho attacks, are the heart and substance of this review book.