The present invention provides compounds of formula (I) wherein R 1 , R 2 , R 3 and R 4 are as defined in the specification, and pharmaceutically acceptable salts thereof, as well as processes for their preparation, pharmaceutical compositions containing them and their use in therapy.
1. A compound, which is 4-(dimethylamino)butyl 2-(4-((2-amino-4-methyl-6-(pentylamino)pyrimidin-5-yl)methyl)phenyl)acetate, or a pharmaceutically acceptable salt thereof.
2. A compound, which is 4-(dimethylamino)butyl 2-(4-((2-amino-4-methyl-6-(pentylamino)pyrimidin-5-yl)methyl)phenyl)acetate.
3. A compound, which is a pharmaceutically acceptable salt of 4-(dimethylamino)butyl 2-(4-((2-amino-4-methyl-6-(pentylamino)pyrimidin-5-yl)methyl)phenyl)acetate.
4. A pharmaceutical composition comprising a compound as claimed in any one of claims 1 to 3 in association with a pharmaceutically acceptable adjuvant, diluent or carrier.