AIDS-005814 AIDS005814 TSAO-6-Methylhypoxanthine TSAO-m6Hx [9-[2',5'-Bis-O-(tert-butyldimethylsilyl)-.beta.-D-ribofuranosyl]-6-methoxypurine]-3'-spiro-5-(4-amino-1,2-oxathiole-2,2-dioxide)