Refers to a Derivative of amino - 5 - 6 - tiazolo [4,5-d] pyrimidine Dione - 2.7 - 3 - substituted of formula (i) wherein R1 is C1 - C6 Hydroxy alkyl R2 is H, alkyl of C1 - C6, among others R3 is H or alkyl C1 - C6 carbonyl with the exclusion of: 2 - amino - 4 - hydroxy - 3 - hydroxy - 3 - [5 - (hodroximetil) tetrahi Drofuran tiazolo IL - 2 -] [4,5-d] pyrimidine 2 - One acetate [2 - (5 - 7 - amino - hydroxy - 2 - oxo - tiazolo [45 - d] pyrimidine - 3 - yl) - 5 - (hydroxymethyl) tetrahydrofuran-3-yl acetate [ILO] 4 - acetoxy - 5 - (5 - 7 - amino - hydroxy - 2 - oxo - tiazolo [4,5-d] pyrimidine - 3 - yl) methyl] tetrahydrofuran-2-ylmethyl 2 - il. It is a selected compound: 2 - amino - 3 - [(2R, 3R, 5S) - 5 - (1 - hydroxy - 2 - hydroxypropyl) il] tetrahydrofuran-2-ylmethyl - 6h tiazolo [4,5-d] pyrimidine - 2.7 - dione among others. It also relates to a composition.Said Compound has agonist activity of Toll like receptor (TLR), being useful in the treatment of infectious diseases such as HBV and HCVSe refiere a un derivado de 5-amino-6H-tiazolo[4,5-D]pirimidin-2,7-diona-3-sustituida de formula (I) en la que R1 es hidroxi, alquilo C1-C6, entre otros R2 es H, alquilo C1-C6, entre otros R3 es H o alquil C1-C6 carbonilo con la exclusion de: 5-amino-7-hidroxi-3-[3-hidroxi-5-(hodroximetil)tetrahidrofuran-2-il]tiazolo[4,5-d]pirimidin-2-ona acetato de [2-(5-amino-7-hidroxi-2-oxo-tiazolo[4,5-d]pirimidin-3-il)-5-(hidroximetil)tetrahidrofuran-3-ilo] acetato de [4-acetoxi-5-(5-amino-7-hidroxi-2-oxo-tiazolo[4,5-d]pirimidin-3-il)tetrahidrofuran-2-il]metilo. Es un compuesto seleccionado: 5-amino-3-[(2R,3R,5S)-3-hidroxi-5-(1-hidroxipropil)tetrahidrofuran-2-il]-6H-tiazolo[4,5-d]pirimidin-2,7-diona entre otros. Tambien se refiere a una composicion. Dicho compuesto tiene actividad agonista del receptor de tipo Toll (TLR), siendo util en el tratamiento de enfermedades infecciosas como VHB o VHC
