Sparteine alkaloids

Feeding experiments utilizing C-, N-, and H-labeled cadaverine (44) and lysine (24) in l upinus augustifolius a source of the lupine alkaloids (—)-sparteine (50, R = H,H) and (+)-lupanine (50, R = O), have been reported which lend dramatic credence to the entire biosynthetic sequence for these and the related compounds discussed above (41). That is, the derivation of these bases is in concert with the expected cyclization from the favored aH-trans stereoisomer of the trimer expected on self-condensation of the 1-dehydropiperidine (45). 

Addition of 2-ethylphenyllithium to dioxolane 25 in the presence of the alkaloid sparteine gives the chiral product 26 in up to 80% e.e. . 

As discussed previously, the chiral alkaloid (—)-sparteine (Scheme 33) forms a biden-tate complex with compounds such as butyllithium, and this chiral base can distinguish... 

Animal sequestration of alkaloids is connected not only with taste but also with the toxicity of these compounds. It has been stated that the toxicity of alkaloids is very selective. Aniszewski has published data with some LDjq coefficients for some alkaloids and some pesticides and compared their toxicity from a selectivity point of view. There was clear evidence that alkaloids (sparteine and lupanine) are much more toxic for vertebrates than are some pesticides (e.g. malafione, phenitrothione, etc.). For invertebrates, pesticides were clearly more toxic than alkaloids. Selective toxicity coefficients (STC) were counted by dividing the LDjg for vertebrates by the LDjg for invertebrates. When the STC is 1.0 there is no selectivity when STC is >1 there is invertebrate selectivity and when <1 there is vertebrate selectivity. Selectivity simply means there exists more ability to toxify the organism. 

Among quinolizidine alkaloids, sparteine and its stereoisomers have been studied in detail by X-ray analysis (42-50). It was demonstrated that proper conformation was not reorganized in monohydrates (42), diperchlorates (43), or methyliodides of a-isosparteine (11) (53). Unlike in the case of a-isosparteine, in spareteine diperchlorate rings C/D appear to have a boat-chair conformation (44-46). On the basis of spectroscopy data a cis conformation for sparteine methyliodide (12) was proposed (57,52). However, radiographic examination (53) of this compound showed it to have the trans conformation (13). 

AicohoJ oxidation can aJso be enantioselective. The best systems reported to date for the selective oxidation of one enantiomer of 7 to 9 depend on the naturally-occurring alkaloid sparteine as a source of chirality. Unfortunately, only one enantiomer of sparteine is available. Peter O Brien of the University of York has developed (J. Org. Chem. 2004,69, 5789) an alternative tricyclic amine 8 that is complementary to sparteine, directing oxidation toward R-7. 

SS -ethylenebis[(R)-cysteine] and SS -ethylenebis[(S)-homocysteine] (L) function as ON-donors in Cu(L — 2H),nH20 (n = 0 or l).197 The CuL2C12 complex of dl-methylsulphonium-methioninate is probably octahedral, whilst the CuL Cl of the derived amide acid may be tetrahedral.196 Tetrahedral CuLC12 complexes of the alkaloid ( —)sparteine and its ( —)a- and (— )P-isosparteine diastereoisomers have been prepared.704-... 

Voltage-gated K+ channels are critical to transmembrane potential- and Ca2+-mediated signalling. Voltage-regulated K+ channels are critically involved in action potentials as described above and such channels are blocked by the legume quinolizidine alkaloid sparteine (lupinidine) as well as by various synthetic psychoactive compounds with disparate effects such as amitryptiline, chlorpromazine, imipramine and phencyclidine. 

Heteroatom-assisted metaUation reactions are very common and especially useful for the selective o-functionalisation of aromatic compounds. More recently, activation of non-aromatic substrates has attracted attention but only a few examples pertinent to protecting groups will be cited here. Kerrick and Beak90 [Scheme 1.53] showed that pyrrolidine protected with a /erf-butoxycarbonyl (Boc) group 53.1 is enantioselectively deprotonated by rcc-BuLi activated by the alkaloid (-)-Sparteine (533).91 Enantioselective deprotonations mediated by (-)-Sparteine were first exploited by Hoppe and co-workers for the retaliation of saturated92 and allylic9394 carbamates. 

Cytisus scoparius (Scotch broom) contains the toxic alkaloid sparteine and related quinolizidine alkaloids, such as isosparteine and cytisine. Sparteine has been used as a marker of drug metabolism by CYP2D6 (28) and is covered in a separate monograph. 

COMMON BROOM Cytisus scoparius, L., Link, Family Fabaceae, is a shrub growing in Europe and Western Asia. The whole aerial part of the shrub, including the seeds, is poisonous due to the presence of the alkaloid sparteine. The sparteine content in the leaves and branch tips is at its highest in the month of May and decreases after flowering, which takes place in June. 

The lupin alkaloids sparteine (98) and lupanine (99) are both derived from lysine, and it is possible on the basis of past work that either one may be a precursor of the other.63 However, recent work suggests that they are derived by divergent pathways.64... 

The alkaloid sparteine was isolated only from the plant Chelidonium majus. It differs in its constitution from the already mentioned groups of alkaloids which were derived from 1-benzylisoquinoline precursors. Schiitte (443) studied the biosynthesis of sparteine in Chelidonium majus by means of radioactive cadaverine. He arrived at the conclusion that in this plant the biosynthesis takes the same pathway as in Lupinus luteus L. 

The plant Chelidonium majus L. has long been known to contain the alkaloid (-)-sparteine (208) (830). Its presence in this plant has been newly confirmed (59). 

The spiro compound 92 and the alkaloid sparteine (85), being racemates, analogously have been successfully resolved by using the optically pure partner... 

Lupinus sericeus contains (—)-7-hydroxy-p-isosparteine and 10, 17-dioxo-P-isosparteine, which are also sparteines tetracyclic quinolizidine alkaloids with a quinolizidine nucleus. Moreover, other alkaloids from this group include epiaphylline and aphylline, alkaloids from L. latifolius, and (—)-lindenianine, an alkaloid from Lupinus lindenianus and Lupinus verbasciformis. Nuttalline (4p-hydroxy-2-oxosparteine) is a tetracyclic quinolizidine alkaloid from Lupinus nuttalli An alkaloid, sparteine can be converted to a-isosparteine or p-isosparteine, which occurs particularly in Cytisophyllum sessilifolium In contrast to aphylline, 17-oxosparteine is known to be s5mthesized only under energetic conditions. ... 

Lupanine lupin Lupinus quinolizidine alkaloids sparteine... 

The majority of the acute studies has been performed on the common lupin alkaloids sparteine and lupanine [39-41]. They both display moderate acute toxicity, the former being the more toxic one. The observed symptoms suggest that alkaloids cause neurological effects leading to loss of motor coordination and muscular control. The effects are generally reversible. 

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