Lycorin

Lycorine (69) was recognized as a potent emetic and a moderately toxic base from the time of its initial isolation from Narcissus pseudonarcissus E. (in about 1877) (48). Since that time its isolation from many other AmaryUidaceae, for example, Lpcom radiate Herb., has served to estabUsh it as the most cosmopohtan alkaloid of the family. TypicaUy, as much as 1% of the dry weight of daffodil bulbs may consist of lycorine (69), which has been reported to... 

Pharmacology. Lycorine was first examined by Morishima wl found it relatively non-toxic to mammals. Given per os or subcutaneous, to the dog or cat, it causes, in small doses, salivation and in large dos vomiting and diarrhoea. It has no special effect on the blood pressure death seems to be due to a generalised collapse. Post mortem —hyper m and ecchymoses in the stomach, intestine, pulmonary pleura and end... 

Lycopodium spp., alkaloids, 752 pharmaeological action, 755 Lycoramine, 406, 408 Lycorenine, 406, 409 Lycorine, 389, 406... 

Lycorine is the most abundant alkaloid in plants of the Amaryllidaceae. Several syntheses of racemic lycorine had been reported prior to our initiation of studies directed at an asymmetric synthesis of the unnatural enantiomer 64. 2 a common theme in all of the syntheses of ( )-lycorine has been the utilization of either an intermolecular or intramolecular Diels-Alder construction of the key C-ring of the alkaloid. This six-membered ring presents a rather formidable synthetic challenge because of the four contiguous stereogenic centers, the trans 1,2-diol moiety, and the juxtaposition of the aromatic substituent and the carbon-carbon double bond. 

The first asymmetric total synthesis of (+)-lycorine is outlined in Scheme 15. While our earlier applications of the Birch reduction-alkylation of chiral benzamide 5 were focused on target structures with a quaternary stereocenter derived from C(l) of the starting benzoic acid derivative, the synthesis of 64 demonstrates that the method also is applicable to the construction of chiral six-membered rings containing only tertiary and trigonal carbon atoms. s... 

Birch reduction-alkylation of 5 with 2-bromoethyl acetate was carried out with complete facial selectivity to give 57. This tetrafunctional intermediate was converted to the bicyclic iodolactone 58 ( > 99% ee) from which the radical cyclization substrate 59 was prepared. The key radical cyclization occurred with complete regio- and facial-selectivity and subsequent stereoselective reduction of the resulting tertiary radical gave 60 with the required trans BC ring fusion.The allylic alcohol rmit of (+)-lycorine was obtained by a photochemical radical decarboxylation, 62 63. 

Hayden RE, Pratt G, Drayson MT et al (2010) Lycorine sensitizes CD40 ligand-protected... 

L-phenylanine alkaloids alkaloids Crinine Eloramultine Galanthamine Galanthine Haemanthamine Lycorine Lycorenine Maritidine Oxomaritidine Vittatine... 

Amaryllidaceae Leucojum vernum Lycorine Homolycorine 2-O-acetyllycorine Leucovernine Acetylleucoverine N-demethylgalanthamine... 

From L-tyrosine, or alternatively from L-phenylalanine, there is one further alkaloid biosynthesis pathway. This is the galanthamine pathway (Figure 38). Galanthamine synthesizes with tyramine, norbelladine, lycorine, crinine, N-demethylnarwedine and Al-demethylgalanthamine. Schiff base and reduction reaction, oxidative coupling and enzyme NADPH and SAM activity occur in this pathway. Schiff base is a reaction for the ehmination of water in formation with the C—N bonds process. 

From norbelladine, through the activity of the SAM, the 4 -0-methylnorbelladine synthesizes, and again is transformed to lycorine, crinine and, by oxidative coupling, to A-demethylarwedine, which is the object of enzyme NADPH activity. Galanthamine is synthesized by transformation trough the activity of the SAM from A-demethylgalanthamine. 

Lycorine is an alkaloid that has attracted attention from both the synthetic community and pharmacologists. Prior synthetic approaches have included inter-and intramolecular Diels-Alder cycloaddition. Based on a similar retrosynthetic disconnection, Padwa and co-workers (106,109) chose to use a push-pull carbonyl ylide cycloaddition with a disubstituted pyrrolidinone core to generate a tricyclic substrate. The major difference for this synthetic smdy was the availability of a labile proton a to the carbonyl moiety (Scheme 4.53). 

Clivia miniata Lindley Jun Zi Lian (whole plant) Clividine, miniatine, lycorine.57 Anticancer, antitumor. 

Hippeastrum hybridum Hortorum Shi Suan Hua (bulb) Lycorine, lycoramine, tazettine, galanthamine. This herb is toxic. Detoxicant, relieve swelling, induce vomitting. 

Hymenocallis speciosa Salisbury Shui Gui Jiao (bulb) Lycorin.60 This herb is toxic. As a vulnerary. 

Lycoris aura (L Her.) Herb. L. longituba Y. Han et Fan L. radiata (L Her.) Herb. Shi Suan (Amaryllis) (rhizome) Galanthamine, lycoremine, lycorine, lycoramine, lycorenine, tazettine, pseudolycorine, dihydrolycorine, homolycorine, lycoricidine, lycoricidinol.33 As a cholinesterase inhibitor, lower blood pressure, stimulate secretion from the pituitary gland, increase natidiuretic hormone secretion. 

Narcissus tazetta L. var. chinensis Roem. Shui Shai (Polyanthus narcissus) (bulb) Lycorine, tazettine, narcitine.49-60 This herb is toxic if overdose. Antiphlogistic, analgesic for boils, abscesses, mastitis. 

Zephyranthes Candida Herbert Cong Lan (White zephyrlily) (aerial part) Lycorine, haemanthidien, nerinine, taxettin.50 For convulsion, hepatitis. 

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