Simple Indole Alkaloids from the Neotropical Rutaceous Tree Raputia simulans

The genus Raputia Aubl. comprises 10 neotropical species of the family Rutaceae belonging to the subtribe Cuspariinae. We report herein the investigation of the dichloromethane extract of the stem bark of R. simulans, which has led to the isolation of indole type alkaloids. The isolation procedure was performed by fast centrifugal partition chromatography (FCPC) and adsorption chromatography and afforded 11 isolates: indole-5-carbaldehyde (1), 7-prenylindole (2), 5-prenylindole (3), verticillatine B (4), 5(but-3'-en-2'-one) indole (5), 5-(2'-methylbut-3'-en-1'-ol)indole (6), 5-[methyl-4'-(2'-methyl-4-oxobutanoate)]indole (7), 5-[4-(methyl)furan-2-yl]indole (8), 5-[4-(methoxymethyl)furan-2-yl] indole (9), 5-[5'-(3-methylfuran-2'(5'H)-one)]indole (10), and 5-(4'-methyl-2',5'-dihydrofuran-2'-yl)indole (11). Metabolites 5-11 were isolated for the first time and bear uncommon substituents on position 5 of the indole moiety.