The structures of paraensidimerin A and C, two bisquinolinone alkaloids from Euxylophora paraensis

Abstract

Single-crystal X-ray diffraction studies and n.m.r. spectral measurements have now shown structure of paraensidimerin A, a bisquinolinone alkaloid from the heartwood of Euxylophora paraensis (Rutaceae), to be (6aα,7β,15β,16aα)-(±-6,6,9,15,18-pentamethyl-6,6a,7,9,15,16,16a,18-octahydro-7,15-methano-8H,17H-quino[3',4' :5',6'] pyrano[3',4':5,6] oxocino[3,2-c] quinoline-8,17-dione (8). Paraensidimerin C is a stereoisomer, (6aα,7β,15β,16aβ)-(±)-6,6,9,15,18-pentamethyl-9,15,16,16a,18-octahydro-7,15-methano-8H,17H-quino [3',4':5',6'] pyrano [3',4': 5,6] oxocino [3,2-quinoline-8,17-dione (9). Possible biosynthetic routes to these and other dimeric quinolinone alkaloids are suggested.