Alchornea alkaloids

Alchornine (73) and alchornidine (74a or 74b) have been isolated by Hart et al. (126) from the bark and leaves of Alchornea javanensis (Bl.) Muell.-Arg. (Euphorbiaceae), a small tree of the New Guinea rain forest. From spectroscopic data and chemical evidence, the major alkaloid alchornine was shown to have the hexahydroimidazo[l,2-a]pyrimidine structure 73. Hydrolysis of a minor alkaloid, alchornidine, with ethanolic potassium hydroxide gave alchornine and 2,2-dimethylacrylic acid. But alchornidine is not simply an A-acyl derivative of alchornine, because mild hydrolysis with dilute acetic acid gives an isomer of 73. This isoalchornine can be shown to be 75, and it is readily converted to alchornine by reaction with alkali. This... 

Two alkaloids which form explosive salts have been identified as the guanidine derivatives pterogynine (28) and pterogynidine (29). The latter compound is believed to be identical to a guanidine alkaloid isolated from Alchornea javensis The structure of pterogynine (28) was confirmed by synthesis. ... 

Another series of hemiterpene alkaloids is found in the genus Alchornea (Euphorbiaceae). In these alkaloids (1-4) the hemiterpene unit constitutes a major portion of the structure (Fig. 37.1) (Hart et al., 1970). 

Other imidazole alkaloids are known from Alchornea (Euphorbiaceae), Casimiroa (Rutaceae), Cassia absus (Fa-... 

Lopes FC, Rocha A, Pirraco A, Regasini LO, Silva DH, Bolzani VS, Azevedo I, Carlos IZ, Soares R (2009) Anti-angiogenic effects of pterogynidine alkaloid isolated from Alchornea glandulosa. BMC Complement Altem Med 9 15. doi 1472-6882-9-15 [pii] or 10.1186/1472-6882-9-15... 

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