2-Chloro-1,7-dihydro-7-methyl-6H-purin-6-one

Step 2: Preparation of 7-methyl-1, 7-dihydro-6H-purin-6-one-2-d A mixture of 2-chloro-7-methyl-1H-purin-6-one (700.0 mg, 3.79 mmol), Zn (2465.06 mg, 37.92 mmol), and DCOOD (1820.35 mg, 37.92 mmol) in CD3OD (10.0 g, 277.78 mmol) and D20 (5.0 g, 250 mmol) was stirred at 600 C. for 16 hours. The reaction mixture was diluted with MeOH (100 mL). The solid was filtrate and the filtrate was concentrated under reduced pressure. The residue was purified by C18 silica gel column eluting with CH3CN/H2O (10 mmol/L NH4HCO3, 5% to 95%, over 30 min) This resulted in the title compound (370 mg) as a white solid.Step 1: Preparation of 2-chloro-1-((3-((3R, 5R)-5-(4-chlorophenyl)-tetrahydrofuran-3-yl)-1, 2, 4-oxadiazol-5-yl)methyl)-7-methyl-1H-purin-6(7H)-one NaH (60%) (39.0 mg, 0.65 mmol) was added batchwise to a solution of 2-chloro-7-methyl-1H-purin-6-one (100.0 mg, 0.54 mmol) in DMF (3 mL) at room temperature under nitrogen and stirred for 1 hour. Then the solution of 5-(chloromethyl)-3-[(3R, 5R)-5-(4-chlorophenyl) tetrahydrofuran-3-yl]-1, 2, 4-oxadiazole (194.0 mg, 0.65 mmol, prepared according to a similar procedure as example 1) in DMF (3 mL) was added. The resulting solution was stirred at 50 C. overnight. The resulting solution was further purified by RP-HPLC to yield the title compound (91 mg, 38%) as a white solid.REFERENCE 1-n-Butyl-2-chloro-1, 7-dihydro-7-methyl-6H-purin-6-one (Compound j) To a suspension of Step 1: Preparation of