The Alkaloids of Pomegranate Root

As expected for a methyl ketone, hypobromite oxidation of A-benzoylisopelletierine gives bromoform (9). Attempts to prepare the compound C10H20NO2CI described by Hess have been unsuccessful (7,8). The procedure described by Hess (19) for the isolation of pelletierine from pomegranate root has been repeated (JJ) and a urethane different from synthetic 3-(2-piperidyl)propanal urethane but identical with synthetic (2-piperidyl)-2-propanone urethane was isolated. 

Gilman and Marion (12) examined a sample of -pelletierine sulfate prepared by C. Tanret in 1880. The IR-spectrum of the base showed carbonyl absorption at 1710 cm i but no absorption due to an aldehyde C—H stretching vibration. The NMR-spectrum showed a three-proton 

In view of the fact that pelletierine and isopelletierine are identical it has been proposed that the name isopelletierine be dropped and that the name pelletierine be used to represent (2-piperidyl)-2-propanone and iV-methylpelletierine to represent the corresponding iV -methyl compound (12). Tanret s pelletierine is thus Z-pelletierine Tanret s isopelletierine, Hess s racemic isopelletierine, and Hess s pelletierine are cZZ-pelletierine. A detailed review of the chemistry of pelletierine has appeared (13). 

Z-Pelletierine has been shown to possess the It configuration (II) at the asymmetric center (14). (— )-Sedridine, known to have the B configuration at the asymmetric center in the piperidine ring, furnishes iZ-( — )-pelletierine when oxidized with chromic acid in aqueous acetic acid. (-I-)-Sedridine gives 5-(- -)-pelletierine on oxidation (14). The method of resolution of racemic pelletierine through salts with the 6,6 -dinitrophenyl-2,2 -dicarboxylic acids (15) has been improved (16). 

The pH dependence of the synthesis of pelletierine from J -piperideine and acetoacetic acid has been investigated (17,18). Pelletierine has been synthesized from cadaverine and acetoacetic acid in the presence of diamine oxidase (19). Pelletierine has recently been isolated from Duboisia myoporoides R.Br. (20), Sedum acre L. (21), and Withania somnifera Dunal (22). 

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