Isolation and identification of amides from Piper callosum. Synthesis of pipercallosine and pipercallosidine

Abstract

Extraction of the roots of the shrub Piper callosum with cyclohexane afforded piperovatine (1)[N-isobutyl-6-(p-methoxyphenyl)sorbamide] and two new amides, the isobutylamides of (2E,4E)-9-(3,4-methylenedioxyphenyl)nona-2,4-dienoic acid and (E)-7-(3,4-methylenedioxyphenyl)hept-2-enoic acid, named pipercallosine (3) and pipercallosidine (14), respectively. The structures of the two new amides have been confirmed by synthesis.