Cl.[N:2]1[CH:7]=[CH:6][N:5]=[CH:4][C:3]=1[C:8]1[C:9](=[O:15])[NH:10][C:11](=[O:14])[NH:12][CH:13]=1.C([O-])([O-])=O.[K+].[K+].Br[CH2:23][CH2:24][CH:25]([O:28][CH3:29])[O:26][CH3:27].O>CN(C=O)C>[CH3:27][O:26][CH:25]([O:28][CH3:29])[CH2:24][CH2:23][N:12]1[CH:13]=[C:8]([C:3]2[CH:4]=[N:5][CH:6]=[CH:7][N:2]=2)[C:9](=[O:15])[NH:10][C:11]1=[O:14]
A mixture of 5-pyrazin-2-yl-1H-pyrimidine-2,4-dione hydrochloride (Prep125, 2.19 mmol), and K2CO3 (302 mg, 2.19 mmol) in DMF (20 ml) was stirred 30 minutes at room temperature. 90% 3-Bromo-1,1dimethoxy-propane (365 μl, 2.41 mmol) was added in two portions during 2 days. Water was added and the mixture was extracted with ethyl acetate. The organic phase was dried (Na2SO4), filtered and evaporated. The crude was purified by flash chromatography eluting with DCM-MeOH—NH4OH (98-2-0.2) to give 221 mg of the title compound (35% yield).
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