Pyrrolidinoindoline Alkaloids from Psychotria colorata1

Fractionation of an alkaloid extract of Psychotria colorata flowers led to the isolation of six alkaloids, identified by UV, 1D and 2D NMR, and MS as (-)-calycanthine, isocalycanthine, (+)-chimonanthine, hodgkinsine, quadrigemine C, and a new alkaloid (1), whose structure was deduced by X-ray analysis to be (8-8a),(8'-8'a)-tetradehydroisocalycanthine 3a(R), 3'a(R).