Lupine alkaloids structure

Wiewiorowski, M. and Wolifiska-Mocydlarz, J. 1964. Structure of the new lupine alkaloid, dehydroalbine. Bulletin of the Polish Academy of Sciences. Chemistry, 12 213-222. 

Wysocka, W. and Brukwicki, T. 1988. Lupin alkaloids. I. Reinvestigation of the structure of N-methylalbine. Planta Medica, 54 522-523. 

Comins, D.L., Zheng, X., and Goehring, R.R. (2002) Total synthesis of the putative structure ofthe lupin alkaloid plumerinine. Organic Letters, 4, 1611-1613. 

During 1993, Daly and co-workers reviewed the alkaloids found in amphibians [5] and Takahata et al. focused on structural assignments and the synthesis of amphibian and polyhydroxylated indolizidines [6]. Wink reviewed the characterisation, natural distribution and biological activity of lupine alkaloids [7] and systematic updates on indolizidine and quinolizidine alkaloids are annually summarized by Michael [8-14]. 

The most common group of alkaloids possessing a quinolizidine nucleus is that of the lupine alkaloids which can simply be classified as bicyclic (lupinine/epilupinine type), tricyclic (cytisine type) or tetracyclic, (sparteine/lupanine or matrine type). Fig. (23). This grouping is made according to structure complexity and without considering biosynthesis, as the detailed biosynthetic pathways are still not completely understood. 

Evidence of the structure proposed for this new glycosidic lupine alkaloid came from the analysis of its positive ion FABMS spectrum that showed peaks at m/z 492 ([M+H] ) and m/z 346... 

Fig. (34). Structures of the tetracyclic lupine alkaloids (-)-6a-hydroxylupanine [219], 4a-hydroxy-13 P-methoxy lupanine, 3P,4a-dihydroxy-13 P-methoxy lupanine and...

These alkaloids have been exhaustively examined only recently although their existence has been known for some 50 years 118). They occur along with other lupine alkaloids in Ormosia species. Their structures are known for the greater part although none has been synthesized. 

Simple bicyclic compounds form a rather small subset of the lupine (or lupin) alkaloids, the overwhelming majority of which have tricyclic or tetracyclic structures based on the quinolizidine motif. These alkaloids are characteristic metabolites of the Papilionoideae, a sub-family of the Leguminosae (Fabaceae), although representative examples have also been isolated from several other plant families. The simple lupine quinolizidines were surveyed in Volume 28 of this treatise (7), while later reviews in Volumes 31 (5) and 47 (9) comprehensively covered all classes of lupine alkaloids, including those containing indolizidine components. Much relevant material is also to be found in the review on the biosynthesis of pyrrolizidine and... 

Known and new lupine alkaloids reported from mid-1993 to mid-1999 are listed in Table I together with their plant sources 318-335). In a number of cases, alkaloids were not isolated, and their identification was based entirely on their gas chromatographic and/or mass spectrometric (GC-MS) characteristics. Several apparently new alkaloids were identified in this way, and their structures should be regarded as tentative until firmer evidence can be obtained. These include a dehydroepilupinine (332), benzoylepilupinine (336), and dihydrolusitanine (347). The putative 4(J-hydroxyepilupinine (334) and 4p-hydroxylupinine (345) were previously detected in several Virgilia species 336), and esters of the former were obtained in sufficiently large amounts for unambiguous spectroscopic characterization. 

Numerous original research articles have been published on various aspects of the chemistry and biochemistry of lupin alkaloids. Some excellent reviews and chapters in books have attempted to provide comprehensive lists of known lupin alkaloids [2-6]. Recent advances, specially on the chemistry of these alkaloids, have appeared in the annual reviews published by the Royal Society of Chemistry [7]. Therefore, in this chapter we summarize the natural occurrence and structural characteristics of newly discovered alkaloids in our recent investigations with brief comments on the spectroscopy of the alkaloids. We also describe the summarized results of biochemical aspects including plant tissue culture and works on isolated enzymes. Chemotaxonomic and pharmacological significance of the alkaloids will be given briefly. 

Lupin alkaloids can be classified into seven structural groups according to the carbon skeleton and the oxidative states (Fig. 1). The alkaloids of lupinine- and... 

Matrine (7) (+)-Ammodendrine (8) (-)-Tsukushinamine-A (9) Fig. 1 Types of structure of lupin alkaloids in Leguminous plants... 

Since, in the H-NNIR spectra of lupin alkaloids, most signals of alicyclic hydrogens appear in the range of S 1-2.5, it is not easy to assign all overlapping signals. However, several characteristic features in the spectra are helpful for structural elucidation. In the IH-NMR spectra of lupanine-type alkaloids, only the signal of Hjoa... 

In the IR spectra of lupin alkaloids, Bohlmann bands are characteristic for molecules having ra -quinolizidine rings and are useful for structural elucidation. The UV spectra of a-pyridone and multiflorine-type alkaloids show absorptions at... 

The CD spectra provide information about the absolute stereochemistry of these alkaloids. The signs of Cotton effects due to the chirality of structurally similar chromophore predicts the absolute configuration of the alkaloids by comparison to that of known compounds. For the quantification of each known alkaloid in the plant materials, the most reliable data are obtained by the combination of normal-phase HPLC, reverse-phase HPLC and capillary GC/MS. The N-oxides of lupin alkaloid can be normally detected by HPLC. 

The present volume reflects these developments, and there is a growing emphasis on bioactive natural products. Articles in this volume include those on structure-activity relationships of highly sweet natural products, chemical constituents of cchinodenns, diterpenoids from Rabdosia and Eremophila sp., structural studies on saponins, marine sesquiterpene quinoncs and antimicrobial activity of amphibian venoms. The reviews on bioactive metabolites of Phomopsis, cardenolide detection by ELISA, xenocoumacins and bioactive dihydroisocoumarins, CD studies of carbohydrate-molybdate complexes, oncogene function inhibitors from microbial secondary metabolites and Gelsemium and Lupin alkaloids present frontier developments in several areas of natural product chemistry. It is hoped that the present volume, which contains articles by eminent authorities in each field, will be received with the same enthusiasm as the previous volumes of this series. 

The lupin alkaloids are found in a wide variety of plants and small trees, such as broom, lupin, gorse, and laburnum, which are used diversely in gardens, for fodder, and as sand-binders. The alkaloids as a group are toxic, but as individuals find some use in veterinary medicine and in insecticide preparations. Chemical similarity rather than plant distribution links these alkaloids, since most of them contain—in actual or modified form—the quinolizidine ring structure (I). This basic... 

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