Erythrinane alkaloids

Up to the most recent reviews published in the years 1995/96 nearly 95 erythrinane and 68 schelhammerane type alkaloids were known (79, 27, 24). In this chapter all the new compounds reported in literature from 1995 to 2004 are listed including the natural source, structure, analytical and spectroscopical informations. 7U1 in all, there are 12 erythrinane and 6 homoerythrinane type compounds compiled in Tables 1 and 2. 

However, the relative small incorporation rate (0.1-0.25% (48)) of the norprotosinomenine (34) into the alkaloid eiythraline (3) and mainly the fact, that the majority of the important isoquinoline alkaloids, 

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Tanaka, H., Etoh, H., Shimizu, H., Oh-Uchi, T., Terada, Y. and Tateishi, Y. 2001. Erythrinan alkaloids and isoflavonoids from Erythrina poeppigiana. Planta Medica, 67 871-873. 

In the Erythrina series, the total synthesis of ( )-erysotramidine (10), an oxo-erythrinan alkaloid, isolated from Erythrina arborescens Roxb.,13 has been... 

Toda, J., Niimura, Y., Takeda, K., Sano, T., and Tsuda, Y. (1998) General method for synthesis of erythrinan and homo-erythrinan alkaloids (1) synthesis of a cycloerythrinan, as a key intermediate to erythrina alkaloids, by Pummerer-type reaction. Chemical e[ Pharmaceutical Bulletin, 46, 906-912, and literature cited therein. 

Erythrina poeppigiana (Walp.) O.F. Cook -mulungu To relax Leaf (tea) Afro-Brazilians [41] Isoflavonoid [121,122,123] arylbenzofuran [124], erythrinan alkaloids [125,126] Antibacterial properties [121] antimicrobial activity [123]... 

Padwa and co-workers ° adapted their tandem cyclization-cycloaddition methodology to culminate in a Ti-cyclization reaction enroute to B-ring homologs of erythrinane alkaloids. Thus, for example, treatment of diazo imide 539 with Rh2(pfb)4 affords the expected cycloadduct 540 in nearly quantitative yield... 

In the late 1960s ring C-homologues of erythrinane alkaloids have been anticipated firom the biosynthetic pathway of certain alkaloids, which are known to be generated from 1-phenethyl-isoquinoline derivatives as precursors (75, 16). Only a short time later such compounds named homoerythrinanes, homoerythrina alkaloids, or schelhammeranes indeed have been found in the plant kingdom 17) (parent compound 2, Fig. 1). 

The present contribution will give a brief classification of the Erythrina alkaloids, a compilation of new alkaloids isolated from 1997 to 2004 covering source, structure, analytical/spectral data, a new pathway of their biosynthesis, an overview of all the synthesis strategies hitherto known for the erythrinane alkaloids including several approaches to the homoerythrinane group, and finally a short review of their biological activities. 

Scheme 2. New biosynthetic sequence of erythrinane alkaloids proposed by Zenk et al. (52)...

But until now there is no experimental evidence for this route concerned, which possibly - with regard to that of the erythrinane alkaloids - will demand a revision. 

Scheme 3. Strategies for the synthesis of aromatic erythrinane alkaloids (5.2.1.) Generation of one alicyclic ring in the final step...

Concerning the non-aromatic erythrinane alkaloids, only one single total synthesis has been achieved until now. Thus, the synthesis of ( )-cocculolidine (15, Fig. 2) has been completed in 0.42% overall yield through 21 steps (54). Furthermore, several synthesis approaches to ring D oxaerythrinane frameworks are known (79). 

Chawla AS, Kapoor VK (1997) Eryt/inna Alkaloids. In D Mello JPF (ed) Handbook of Plant and Fungal Toxicants. CRC Press (Erythrinane alkaloids exclusively)... 

Tanaka H, Tanaka T, Etoh H, Goto S, Terada Y (1999) Two New Erythrinan Alkaloids from Erythrina x bidwillii. Heterocycles 51 2759... 

Tanaka H, Etoh H, Shimizu H, Oh-Uchi T, Terada Y, Tateishi Y (2(X)1) Erythrinan Alkaloids and Isoflavonoids from Erythrina poeppigiana. Planta Med 67 871... 

Tsuda Y, Hosoi S, Ishida K, Sangai M (1994) Chiral Synthesis of Erythrina Alkaloids (2). Synthesis of enantio-Typc Erythrinan Alkaloids Utilizing Asymmetric Acylation and Kinetic Resolution of Diastereomers. Chem Pharm Bull 42 204... 

Haruna M, Ito K (1976) Convenient Method for Syntheses of Erythrinan Alkaloids. J Chem Soc Chem Commmun 345... 

Keywords Leguminosae-Fabaceae, Erythrina, erythrinane alkaloids, synthesis, biosynthesis, pharmacology... 

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