5-amino-3-[(2R,3R,5S)-5-[[tert-butyl(diphenyl)silyl]oxymethyl]-3-(1-fluoro-1-methyl-ethyl)tetrahydrofuran-2-yl]-6H-thiazolo[4,5-d]pyrimidine-2,7-dione (HCID 137190223)|Huagongshe