6-(4-Methoxyphenyl)dibenzo[d,f][1,3,2]dioxaphosphepine 6-sulfide AIDS-147981 AIDS147981 Methyl 4-(6-sulfidodibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)phenyl ether NSC678866 {Dibenzo[d,f][1,3,2]dioxaphosphepin,} 6-(4-methoxyphenyl)-, 6-sulfide