Erythrina alkaloids structure determination

Only two normal Erythrina alkaloids have been isolated from Cocculus species, dihydroerysodine (47) (75) and dihydroerysovine (44), the latter recently from C. trilobus (57). Neither alkaloid has been found in Erythrina species. The structure 44 for dihydroerysovine was deduced from the spectroscopic evidence and by methylation using diazomethane to give the known dihydroerysotrine (38). The positions of the aromatic substituents were determined by detailed NMR experiments using NOE and INDOR techniques (see Section II,C,2d). 

This report embodies the work published on the isolation, structure determination, and synthesis of Erythrina, Cocculus, Cephalotaxus, and other related alkaloids. 

A review on Erythrina and related alkaloids covering the literature from Noventer 1966 to the end of May 1979 has appeared it sutnnarizes the work published on isolation, structure determination, biosynthesis, synthesis and pharmacolc of Erythrina, Hcmoerythrina, and Cephalotaxus alkaloids, and the... 

Erysodienone (1 R = H), a compound previously unknown in Nature, has been isolated from Erythrina lithosperma. The isolation of erybidine (2) from E. xbidwilli Lindl. is of biogenetic interest. Its structure was determined by spectral studies, Hofmann degradation, and synthesis from erysodienone (1 R = H). This species has been shown previously to elaborate Erythrina alkaloids. 

In recent years mass and nmr spectral methods have been increasingly utihsed in the structure determination of Erythrina alkaloids. Mass spectra have proved particularly useful in preliminary screening of Erythrina species for their alkaloid content especially in conjunction with gas chromatography (Games et al. 1974, Hargreaves et al. 

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