3-Methoxy-6a,13a-dihydro-6H,7H-chromeno[4,3-b][1,3]dioxolo[4,5-g]chromene 6a,13a-Dihydro-6H,7H-chromeno[4,3-b][1,3]dioxolo[4,5-g]chromen-3-yl methyl ether AIDS-148682 AIDS148682 NSC681606