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Terpenoids Subject

In order to expand the chemical sampling of this species to its entire range and to investigate xylem terpenoids in detail, Zavarin et al. (1990) collected wood samples from 191 trees from 20 areas, isolated the monoterpene fractions, and subjected them to GLC analysis. The major component was identified as a-pinene, with P-pinene, 3-carene, and limonene as lesser, but stiU important, components. Minor... [Pg.151]

In 1965 Seshardri et al. described the isolation of an unknown terpenoid acid B obtained from the lichens of Lobaria retigera in the western Himalayas [8]. (Note that this annotation bears no relation to the subsequent nomenclature later defined by Corey and Shibata.) Four collections had been made in the summer of 1962 from under the Rutba plants in the Valley of Flowers (12,500 feet) and on the way to Hemkund Lokpal (13,500 feet) and from underneath rocks and from pine trees in Ganghariya (10,000 feet). The samples were subjected to a series of increasingly polar extractions (petroleum ether, diethyl ether, acetone). The unknown terpenoid acid B was present in all petroleum ether extracts, except that of the sample obtained from the Valley of Flowers, in compositions ranging from 0.47 % to... [Pg.236]

The interaction between Drosophila, yeasts and columnar cacti of the Sonoran Desert has been the subject of much recent interest (37) As a coevolved system, perhaps more is known about this interaction than any other. The chemistry of the cacti (70 spp.) has been postulated to play a significant role in the establishment of this system (38 ), but this was based upon reports of a relatively small number of relatively simple alkaloids, and a small number of terpenoid compounds. Only recently, the diversification of plant compounds has been discovered to be much greater (5). In their section on alkaloids in the above work, BajaJ and McLaughlin report the presence of some thirty-five structures. In addition, I have been able to isolate some sixty triterpenoid glycosides (structures were not determined) and more were detected but not Isolated. [Pg.283]

The format of these Reports has remained relatively constant from year to year to facilitate the location of subject matter. However, this year two changes have occurred. Firstly, as an experiment, the information on biosynthesis is contained within the chapters dealing with the individual group of terpenoids rather than as a separate chapter. Secondly, the steroid section has been recast to minimize overlap. A report of the application of physical methods to steroids forms one chapter whilst steroid reactions and partial syntheses are reported in the second. Total synthesis will be reviewed biennially. [Pg.309]

Angular alkylations of fused-ring ketones are an important step in syntheses of terpenoids, steroids and related natural products. The steric course of these alkylations has therefore been the subject of several systematic investigations and has been reviewedl 3 71. Alkylation of the lithium enolate 38 (R = H) derived from octahydro-1 (2//)-naphthalenone (1 -decalone) primarily yields the civ-fused octahydro-8a-methyl-l(2F/)-naphthalenone (39, R = H)35,62,79. Due to steric reasons, the lithium enolate 38 (R = CH3), with an angular methyl group, provides the irans-fused product 39 (R = CH3). [Pg.714]

After administration of milligram Ginkgoselect Phytosome formulation (24% ginkgo-flavone glycosides and 6% terpenoids in phospholipid complex, 1 2). Abbreviations. N, number of subjects i.v., intravenous C ax, maximum plasma concentration tmux, time at ti/2(p), elimination half-life CL/F, clearance with regard to bioavailability F/F, volume of distribution with regard to bioavailability. [Pg.211]

B-79MI10405)) and to attempt to present a comprehensive list would be a mammoth task. A number of general introductory texts are available which provide an overview of the subject and an entrance to the more specialist literature (e.g. B-78MI10401, B-78MI10402, B-81MI10402, B-81MI10403). A more comprehensive view of the literature from 1971 to 1978 is provided by The Royal Society of Chemistry series Biosynthesis (Specialist Periodic Reports), volumes 1 to 6, and by various chapters of the companion series Terpenoids and Steroids , Alkaloids and Peptides and Proteins . [Pg.109]

Many furan derivatives have been examined by X-ray diffraction methods, and natural products (especially the terpenoids) have provided numerous, interesting subjects for study. Some work has also been done by electron diffraction methods and, more recently, by microwave spectrometry. The bond lengths and angles determined for furan and assembled... [Pg.535]

There is a huge variety of plant defensive secondary metabolites that has been the subject of major phytochemical [1-6] or pharmacological and toxicological [7-12] compilations. This structural complexity is very briefly reviewed below before considering those plant bioactives with signal transduction targets. The major groups are the phenolics, the terpenoids and the alkaloids as well as bioactives structurally related to... [Pg.513]

Terpenoids are subjected to aminomethylation in order to intrtxiuce a basic moiety into the molecule. The reactive site of the substrate is usually an alkene or alkyl ketone group however, unsaturated derivatives of type 490 arc obtained from terpenes suitably functionalized by the alkyne moiety. ... [Pg.257]

Since last year s Specialist Report, the emphasis in the di terpenoid alkaloid field has focused on structure determination, both by X-ray crystallography and by chemical and spectral methods. Some interesting synthetic approaches to diterpenoid alkaloids have also been reported. The total volume of work on diterpenoid alkaloids reported this year, however, is much less than in Chapter 16 of last year s Report, which covered a longer period and was intended to give a background to the subject. [Pg.247]

This second volume, which reviews the alkaloid literature from July 1970 to June 1971, approaches more closely the standard Specialist Periodical Report originally envisaged by the Chemical Society and adopts a form which, with minor variations, will very probably be followed in subsequent volumes. Once again the whole field of alkaloid chemistry has been reviewed, with the exception of the Steroidal Alkaloids of the Solanum and Veratrum Groups. The omission of these groups in the first volume was deliberate their inclusion in the second volume was intended, but proved to be impracticable, and we hope to remedy this omission in the third volume. It is fortunate, however, that this particular area can quite properly be discussed in a volume devoted to alkaloids or in one devoted to steroids and for a brief review of recent developments in this subject the reader is meanwhile referred to the Specialist Periodical Report on Terpenoids and Steroids, Volume One (Senior Reporter Dr. K. H. Overton). [Pg.301]

It is now apparent, however, that the Specialist Periodical Reports on "The Alkaloids", "Biosynthesis", "Terpenoids and Steroids" and "Aliphatic and Related Natural Product Chemistry" are not financially viable in their present book format and in 1984 they are to be replaced by a review journal to be called "Natural Product Reports". The new journal is to be published every two months and will continue to give comprehensive annual surveys of the four areas of natural product research additional articles on subjects not covered by existing Specialist Periodical Reports on topics such as chemotaxonom.y and enzymology and on advances in physical techniques will be included periodically and author and subject indices are to be provided. The flexible production timetable should ensure more rapid publication of manuscripts compared with S.P.R. s. In order to maintain continuity the S.P.R. Senior Reporters are members of the Editorial Board of Natural Products Reports and in the case of the alkaloid chapters it is expected that the present authors will contribute to the Journal. We all hope that the support we have received over the years from alkaloid chemists will be extended to this new and exciting venture. As always comments and suggestions will be much appreciated. [Pg.340]

The book is aimed primarily at university undergraduates, postgraduates and professional chemists who wish to build up their knowledge of terpenoid chemistry. It is intended to serve as a general introduction to the exciting field of terpenoid chemistry. Terpenoids play an important part in all our lives, from perfumes through insect pest control to pharmaceuticals such as steroid hormones and the anti-cancer drug paclitaxel. The subject therefore also serves to illustrate the importance of chemistry in everyday life. [Pg.419]

Terpenoid Indole Alkaloids.—Monoterpenes have been the subject of a comprehensive review which includes these alkaloids. Indole alkaloids have been classified according to their biogenesis and another review discusses the application of tritium labelling in biosynthetic studies on these alkaloids as well as several others. [Pg.1]

It is usual to classify alkaloids (basic nitrogenous metabolites) according to the amino acids (or their derivatives) from which they arise. Thus, the most important classes are derived from the amino acids ornithine, lysine, phenylalanine, tyrosine and tryptophan, and the skeletons of these amino acids are retained largely intact in the alkaloids derived from them. However, this type of classification is often criticized because it fails to include those alkaloids that are derived from a mixed biogenetic pathway (e.g. polyketide or terpenoid) with incorporation of a nitrogen atom, ultimately from ammonia. The alkaloids that are the subject of this review are excellent examples of such compounds and they are often known as pseudoalkaloids. [Pg.574]

In the presence of NADPH, HMG-CoA is reduced to MV A. The reductase (/i-mevalonate NADP oxidoreductase, CoA acylating, EC 1.1.1.34) is one of the few well-characterized plant enzymes, as it is a major site of regulation of terpenoid biosynthesis. The HMG-CoA reductase has been purified from a number of species, and its characteristics and regulation mechanisms have been the subject of extensive reviews (70,72,74). The C. roseus enzyme(s) has not yet been purified, although a gene encoding HMG-CoA reductase has been cloned (see later discussion) (88,89). [Pg.233]


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See also in sourсe #XX -- [ Pg.150 , Pg.177 ]




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