(7aR,12aS)-7a-(1,1-Dimethyl-2-propenyl)-7a,12-dihydro-3-[(E)-(1H-imidazol-4-yl)methylene]-6,12-dimethoxy-1H,5H-imidazo[1',2':1,2]pyrido[2,3-b]indole-2,5(3H)-dione

A complex alkaloid obtained from the mold Penicillium oxalicum, this base crystallizes from methyl nitrite as colourless needles. It is optically active having a specific rotation of [α]²²_D- 45° (c 0.3, MeOH). The structure has been confirmed by X-ray crystallography, the base forming orthorhombic crystals having space groupP2 12121, a = 10.84, b = 15.70 and c = 13.24 A with Z = 4.