BIOMIMETIC SYNTHESIS OF NITRARAMINE

The synthesis of a possible biosynthetic precursor (9) of nitraramine (1) is described, utilizing N-Boc-piperidone as an equivalent of dideh ydropiperidine 4. Heating this reactive, achiral intermediate 9 in aqu eous solution results in the stereoselective formation of natural nitr aramine via three successive cyclization reactions. Since nitraramine and several other Nitraria alkaloids are obtained from Nitraria specie s in racemic form, this synthesis provides additional support for our hypothesis of non-enzyme-catalyzed formation of these alkaloids.