(+/-)-Aza-Calanolide A 2H,10H-Dipyrano[2,3-f:2',3'-h]quinolin-10-one, 6,7,8,9-tetrahydro-8-hydroxy-2,2,6,7-tetramethyl-12-propyl-, rel-(6R,7S,8S) AIDS-032940 AIDS032940