Erythrina and 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 

Preliminary studies of the alkaloid content of the leaves of four Erythrina species revealed the presence of a- and 6-er3 hroidines (1,2) in E. berteroana, E. poeppigiana,and E. salviiflora but not in E. macrophylla. 

salviiflora. The most comnonly occurring alkaloids, also usually present in greatest abundance, e.g., er37sodine (3a) and erysopine (3b),were found in small amounts only in E. poeppigiana. The presence of erythratidine (4a) was noted in E. macrophylla, E. poeppigiana,and E. salviiflora, but not in 

berteroana. Er3 1iraline (3c) was present only in E. macrophylla. Erybidine (5), erythratidinone (4b), and isoboldine (6) were found only in E. poeppigiana. Some of the 11-hydroxylated derivatives of Erythrina alkaloids were also tentatively identified from their mass spectra. Ihus erythrinine (3d), 11-hydroxy-erythratine (4c), and 11-hydroxyerysotinone (4d) were detected in F. macrophylla, whilst E. poeppigiana contained 11-hydroxyerythratidine (4e) and its C-2 

americana and conmented that these were the active principles responsible 

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

Inubushi, H. Furukawa, and M. Ju-ichi, Tetrahedron Lett., 1969, 153 Chem. Pharm. Bull., 1970, 18, 1951. 

Ju-ichi, Mukogawa Joshi Daigaku Kivo, Yakugaku Hen, 1979, 27, 13 (Chem. Abstr., 1981, 94, 188 602). 

Reagents i, ArCH2CH2NH2 ii, (COCl)2 iii. PPA or an appropriate Lewis acid 

The dibenzazonine (21), related to a biosynthetic precursor of Erythrina alkaloids, was obtained in 36% yield by intramolecular oxidative coupling of tetramethoxytrifluoroacetamide (20) by thallium(in) trifluoroacetate in tri-fluoroacetic acid at 25 °C.17 The trifluoroacetyl group was readily removed by alkaline hydrolysis, and the H n.m.r. spectrum of the free base confirmed that coupling had taken place para-para (with respect to the 3-methoxy-group of each aromatic ring). 

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Two alkaloids possessing the 4-azaazulene skeleton have been isolated from leaves of Dysoxylum lenticellare (Meliaceae), namely 3-e/u-schelhamericine (188a) and dihydrohomoerysotrine (188b) (83MI2). For a report on Erythrina and related alkaloids, see (84MI1). 

The seventh volume of The Alkaloids follows the policy and format adopted in preyious volumes. Most sections are concerned with literature published during July 1975— June 1976, but the three Chapters on Amaryllidaceae and Related Alkaloids, Erythrina and Related Alkaloids, and Miscellaneous Alkaloids cover the two-year period up to June 1976. 

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