[NH2:1][C:2]1[N:7]=[C:6]([CH3:8])[C:5]([Br:9])=[C:4]([CH3:10])[N:3]=1.[C:11]1(C)[CH:16]=[CH:15][C:14](S(O)(=O)=O)=[CH:13][CH:12]=1.O>C1(C)C=CC=CC=1>[CH3:14][C:13]1[N:1]([C:2]2[N:7]=[C:6]([CH3:8])[C:5]([Br:9])=[C:4]([CH3:10])[N:3]=2)[C:16]([CH3:15])=[CH:11][CH:12]=1To a stirred solution containing 2.00 g (9.89 mmol) of 2-amino-5-bromo-4,6-dimethylpyrimidine (3) in 16 mL of anhydrous toluene were added 1.36 mL (11.5 mmol) of 2,5-hexadienone followed by 96 mg (0.50 mmol) of p-toluene sulfonic acid. The reaction mixture was stirred at reflux overnight under argon atmosphere. The reaction mixture was poured into 150 mL of water and then extracted with a portion of 200 mL of ethyl acetate. The organic solution was washed with a portion of 150 mL of brine, dried (MgSO4) and then concentrated under diminished pressure. The residue was purified by chromatography on a silica gel column. Elution with hexanes-ethyl acetate 5:1 gave the expected product as light yellow crystals: yield 2.23 g (81%). 1H-NMR (CDCl3) δ 5.90 (s, 2H), 2.67 (s, 6H), 2.34 (s, 6H); 13C-NMR (CDCl3) δ 166.92, 155.32, 129.56, 118.62, 108.74, 24.90, 14.50.
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