6-Hydroxy-1-methyl-5,12-dioxo-5,12-dihydrobenzo[h]chromeno[5,4,3-cde]chromen-10-yl 3,4-O-benzylidene-6-deoxy-2-O-(6-deoxyhexopyranosyl)hexopyranoside AIDS-136833 AIDS136833 NSC639832