Aglaia rubiginosa (Hiern) Pannel (Meliaceae) was collected from a peat swamp forest in Narathiwat province, Thailand in May 1994. A voucher specimen (No ES-94051) is deposited in the herbarium of the Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand. This genus contains bis-amides (1 —6), some of which have shown antileukemic activity (3, 6) while another (7) has shown antiviral activity. The present work deals with the isolation and identification of a new bis-amide, aglairubine (1), from the leaves of this plant. The methanolic extract of the leaves (7 kg) was evaporated under reduced pressure. The residue was preadsorbed on kieselguhr and successively eluted with hexane, chloroform, and methanol, respectively. The chloroform-soluble fraction (60g) was suspended in dilute acetic acid. The acid-soluble filtrate was basified with ammonium hydroxide and exhaustively extracted with chloroform. The final chloroform residue (6.5 g) was purified by column chromatography using basic aluminium oxide (200 g, Merck 1076) with benzene-ethanol (19:1) as the eluent to afford aglairubine (469mg). Using a similar method, additional amount of aglairubine (162 mg) were obtained from the methanol-soluble fraction (820 g). Aglairubine (N-[4-( 1 -oxo-3-phenyl-2-propenyl )aminobutyl ]- 3-methyl-3-pyrrolin-2-one): colorless needles, m.p. 116— 117 °C, ElMS: m/z (%) = 298 IMI (0.2), 160(5.4), 131 (100), 103 (40), 82 (12.3), 77 (17.7); 1H-NMR (CD3OD, 500 MHz): ö = 7.54 (2H, dd,J= 15, 8Hz, H-5", H-9"), 7.52 (IH, d,J= 15Hz, H-3"), 7.38 (2H, m, H-6", H-8"), 7.36 (IH, m, H-7"), 6,59 (IH, d,J = 15Hz, H-2"), 6.33 (IH, tq,J =6,1.7Hz, H-4), 4.23 (2H, dq,J = 6, 1.1 Hz, H-5), 3.32 (2H, m, H-4'), 3.28 (2H, m, H-i'), 1.83 (3H, dt, J = 1.7, 1.1 Hz, H-6), 1.60 (4H, m, H-2', H-3'); 13C-NMR (CD3OD, 125 MHz): ö = 172.0 (C-2), 168.6 (C-i"), 140.8 (c-3"), 136.2 (C-4"), 135.9 (C-4), 132.5 (C-3), 130.7 (C-7"), 130.1 (C-6", C-8"), 129.4 (C-5", C-9"), 121.8 (C-2"), 59.5 (C-5), 40.3 (c-I'), 40.2 (C-4'), 27.8 (C-2' and C-3'), 13.0 (C-6).