(4aR,6aR,6bS,8aR,11R,12S,12aR,14bR)-4,4,6a,6b,8a,11,12,14b-Octamethyl-1,4,4a,5,6,6a,6b,7,8,8a,9,10,11,12,12a,14,14a,14b-octadecahydro-2H-picen-3-one .alpha.-Amyrenone 638-96-0 AIDS-082909 AIDS082909 Urs-12-en-3-one