Pyrrolidine, Tropane, Piperidine, and Polyketide Alkaloids

Biological Activity of Tropane Alkaloids Distribution of Tropane Alkaloids Piperidine Alkaloids Alkaloids from Piper Species Piperine Alkaloids Involving Condensation with Acetate/Malonate Sedum Alkaloids Lobelia Alkaloids Lycopodium Alkaloids Piperidine Alkaloids in Insects Polyketide-Derived Alkaloids Coniine 

Polyketide Alkaloid Phytotoxins Polyhydroxy Piperidine Alkaloids References 

A number of alkaloids are derived from ornithine and lysine by decarboxylation, conversion by amine oxidases to the corresponding aldehyde, and cyclization to a 5-membered ring system (pyrrolidine alkaloids) and a 6-membered ring system (piperidine alkaloids). Several other alkaloids that coincidentally have similar structures have been discussed under the groups of alkaloids to which they are most closely related. 

Both H- and C-NMR spectra of the alkaloid types above and the nuclear magnetic resonance (NMR) and mass spectroscopy (MS) analysis of tropane alkaloids have been reviewed (Crabb, 1982 Lounasmaa, 1988). 

The approximately 80 known pyrrolidine alkaloids possess a 5-membered nitrogen-containing ring (Massiot and Delaude, 1986 Binder, 1993). Several subgroups of pyrrolidine alkaloids arise by condensation of these units with other molecules, Pyrrolidine bases usually are modified by additional Schiff-base formation, Mannich condensation, and aldol-type processes to yield other alkaloids of tiiis general class. For example, condensation of pyrrolidine derivatives with nicotinic acid is involved in the formation of pyridine alkaloids such as nicotine see Chapter 28). Pyrrolidine units react with acetyl- or malonyl-CoA and condense via a Mannich condensation to form compounds such as hygrine and cuscohygrine and tropane alkaloids see below). 

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