1-(2',5'-bis-O-(t-butyldimethylsilyl)ribofuranosyl)-3'-spiro-5''-(4''-amino-1'',2''-oxathiole-2'',2''-dioxide)-3-ethylthymine
1-(2',5'-bis-o-(t-butyldimethylsilyl)ribofuranosyl)-3'-spiro-5''-(4''-amino-1'',2''-oxathiole-2'',2''-dioxide)-3-ethylthymine