NEW MATERIAL:A compound expressed by formula I [X represents formula II (R2 represents H, lower alkyl, lower alkenyl, aryl, group expressed by formula III, etc.); R1 and R3 represent H, lower alkyl, cycloalkyl, lower alkenyl, aryl, etc.; R4 represents the same species as R1 or group expressed by formula IV].
USE: An antitumor agent.
PREPARATION: For example, methyl iodide is added to a suspended solution of DC-45A2 and silver oxide in acetone and stirred for 5.5hr at room temperature, followed by filtration, concentration under reduced pressure and separation with silica-gel chromatography. Then each fraction corresponding to the Rf value developed by silica-gel chromatography is concentrated under reduced pressure and each concentrate is purified again with the silica-gel chromatography. The purified product is crystallized in acetone-ether to afford the compound expressed by formula I.
KURODA TOKUYUKI
SUGAYA TORU
UENO HIDEO
MORIMOTO MAKOTO
FUJIMOTO KAZUHISA
