Indole alkaloid indolizidine

Iminium ion-vinylsilane cyclizations closely related to the one described here have been used to prepare indolizidine alkaloids of the pumiliotoxin A and elaeokanine families, indole alkaloids, amaryllidaceae alkaloids, and the antibiotic (+)-streptazolin. The ability of the silicon substituent to control the position, and in some cases stereochemistry, of the unsaturation in the product heterocycle was a key feature of each of these syntheses. 

The Aspidosperma family of indole alkaloids has inspired many synthetic strategies for the construction of their pentacyclic framework of the parent compound aspidospermidine (366), since the initial clinical success of two derivatives, vinblastine (10) and vincristine, as anticancer agents. The alkaloids such as (-)-rhazinal (369) and (-)-rhazinilam (6) have been identified as novel leads for the development of new generation anticancer agents [10,11]. Bis-lactams (-)-leucunolam (370) and (-t-)-epi-leucunolam (371) have bio-genetic and structural relationships with these compounds [236]. Recently, enantioselective or racemic total syntheses of some of the these natural product were achieved. One successful synthesis was the preparation of the tricyclic ketone 365, an advanced intermediate in the synthesis of aspidospermidine (366), from pyrrole (1) (Scheme 76) [14]. The key step is the construction of the indolizidine 360, which represents the first example of the equivalent intramolecular Michael addition process [14,237,238]. The DIBAL-H mediated reduction product was subject to mesylation under the Crossland-... 

Imidazole alkaloids, 263 Indole alkaloids, 257-263 dehydrobufotenine, 262 dimeric, 261 indole amines, 261-262 pseudophrynamines, 257-261 trypargine, 262-263 Indole amines, 261-262 Indolizidines... 

A range of alkaloids including isoquinoline, indolizidine, benzazepine, oxazine, quinoline and indole alkaloids were examined as potential inhibitors of eukaryote protein kinases such as PKC, MLCK and PKA. Only three oxazine alkaloids and four isoquinoline-based alkaloids and inhibitors of the protein kinases tested. A narrow structural and protein kinase target specificity, was observed. (+)-Boldine (39) and bulbocapnine (40) are specific for MLCK, while apomorphine (41) and sanguinarine (42) are for PKA. 

Nickel-catalyzed reductive cyclizations and couplings in the syntheses of heterocycles including coupling of alkynes with epoxides and syntheses of indole and indolizidine alkaloids 04AG(E)3890. 

Hie first, by Lounastnaa and Hanhinen, updates an area of indole alkaloids which has been neglected in the series for over 30 years, namely, the ajmaline group of alkaloids, where numerous advances in chemistry and biosynthesis have been made recently. The second chapter by Michael reports on the progress made in a vast area of alkaloid chemistry, those alkaloids with either an indolizidine or a quinolizidine nucleus derived from plant, marine animal, and fungal sources. 

Alkaloids can be divided into different t q3es according their pure chemical structures pointing first at the alkaloid base, a basic chemical nucleus. The following are basic types of alkaloids acridones, aromatics, carbo-lines, ephedras, ergots, imidazoles, indoles, bisindoles, indolizidines, manza-mines, oxindoles, quinolines, quinozolines. quinolizidines, phenylisoquinolines, phenylethylamines, piperidines, purines, pyrolidines, pyrrolizidines, pyrro-loindoles, pyrydines, sesquiterpenes, simple tetrahydroisoquinolines, stereoids, tropanes, terpenoids, diterpenes, and triterpenes. 

Gercideae. (a) The occurrence of alkaloids. Key to branches leading to families that accumulate quinolizidines, pyrrolizidines (No. 1 see arrows) Erythrina (No. 3) indolizidines (No. 4) p-carbolines (No. 5) or simple indoles (No. 2) are marked. The rbcl sequences used (1400 bp) derived from Kass and Wink, 1997a,b Wink and Mohamed (2003). Trees were reconstructed with maximum parsimony. 

No alkaloids had been obtained from the family Elaeocarpaceae until a CSIRO group began a study of certain Elaeocarpus spp. from New Guinea. Amongst a score or so of alkaloids they isolated was a new indole base, elaeocarpidine (7), but most of the others had novel indolizidine structures exemplified by elaeokanine C (8), elaeokanidine A (9) and elaeocarpine (10) [28]. 

Novel routes to p5UToles, indoles, and carbazoles - Applications in total synthesis of alkaloids including fused indolizidines, yohimbanes, Amarylhdaceae alkaloids, and carbazoles 05COC1601. 

There is no uniform classification for the A. In the literature divisions according to origin (examples Aconitum, Amaryllidaceae, Aspidosperma, cactus, Catharanthus, Cephalotaxus, Cinchona, coca, Corydalis, curare, Dendrobates, ergot, Erythrina, Iboga, Lycopodium, Maytenus, opium, Rauvol-fia, Senecio, Strychnos, tobacco, Vinca alkaloids, salamander, Solanum, Veratrum steroid alkaloids) in addition to divisions according to chemical structure (examples aporphine, benzylisoquinoline, bis-benzylisoquinoline, berberine, carboline, diterpene, inudazole, indole, indolizidine, isoquinoline, lupinane, macrocyclic, morphine, peptide, / -phenyl-ethylamine, piperidine, purine, pyridine, pyrrolidine, pyrrolizidine, quinoline, quinolizidine, quinucli-dine, spermine, spermidine, steroid, terpene, tro-pane, tropolone alkaloids) are used. 

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