BIOMIMETIC SYNTHESES OF ALKALOIDS BASED ON TETRAHYDROPYRIDINE

Many of the alkaloids found in Nitraria and Lupine species can be envi saged to arise from two simple building blocks, namely tryptamine and tetrahydropyridine. In particular in the Nitraria species, the alkaloi ds occur as racemates, in some cases, despite multi stereocenters. We assume that these alkaloids might be formed without interference of en zymes via spontaneous reactions of highly reactive intermediates. By c arrying out a biomimetic approach many of these alkaloids were obtaine d via chemical synthesis, based on reactive precursors. The paper revi ews the preparation of racemic Nitramine, Lupinine, Nazlinin, Nitrarin e/Nitramidine, Spartein and Nitraramine from tryptamine and the trimer of tetrahydropyridine, based on imine-enamine chemistry.