142102-79-2 2',5'diSilySpiroT AIDS-003918 AIDS003918 TSAO-m3T TSAO-m^3T TSAO-me^3-T Thymidine, 3-methyl, [2',5'-bis-O-(tert-butyldimethylsilyl)-.beta.-D-ribofuranosyl]-3'-spiro-5-(4-amino-1,2-oxathiole-2,2-dioxide) Tsao-m(3)T