Pyrrolizidines biogenesis

The synthesis of pyrrolizidine derivatives by condensation of di-(4-oxo-ra-butyl)amine is considered in Section V in conjunction with the biogenesis of naturally occurring pyrrolizidines. 

Biogenetic pathways leading to naturally occurring pyrrolizidine bases were proposed by Robinson, Schopf, and Lukefi (see, e.g., refs. 119-121) in their publications concerned with the biogenesis of alkaloids. The most probable precursors of the pyrrolizidine system are commonly accepted to be ornithine (176), hydroxyomithine (177), and their biogenetic equivalents. It is noteworthy that ( + )- -hydroxy-jV-methylnorvaline (178) (structurally related to ornithine) was isolated... 

A Papua New Guinea sponge, Pseudoceratina sp., contains the unusual alkaloids ceratamines A (1142) and B (1143), and a biogenesis involving histidine and tyrosine is proposed (1173). The fermentation broth from Aspergillus fischeri var. thermomutatus has yielded CJ-12662 (1144) and UK-88051 (1145) (1174). The former metabolite was confirmed by X-ray spectroscopy and partial synthesis. A marine-derived Streptomyces sp. produces the novel pyrrolizidine 5-chlorobohem-amine C (1146), which was shown not to be an isolation artifact (1175). The Chinese medicinal plant Huperzia serrata has furnished 2-chlorohyperzine E (1147) (1176). 

Fig. 30.2. Biogenesis of pyrrolizidine alkaloids (Spenser, 1985 used with permission of the copyright owner, the International Union of Pure and Applied Chemistry, Oxford).

Hartmann T, Ober D (2008) Defense by pyrrolizidine alkaloids developed by plants and recruited by insects. In SchaUer A (ed) Induced plant resistance to herbivory. Springer, New York Hartmaim T, Witte L (1995) PytroUzidine alkaloids chemical, biological and chemoecological aspects. In Pelletier SW (ed) Alkaloids chemical and biological perspectives. Pergamon, Oxford Hashimoto T, Yamada Y (1994) Alkaloid biogenesis molecular aspects. Annu Rev Plant Physiol Plant Mol Biol 45 257-285... 

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