Dimethylformamide → Methyl 1-(2-ethoxyethyl)-5,7-dioxo-4,5,6,7-tetrahydro-1h-pyrazolo[4,3-d]pyrimidine-3-carboxylate
Reaction equation
[NH2:1][C:2]1[C:3]([C:15]([O:17][CH3:18])=[O:16])=[N:4][N:5]([CH2:10][CH2:11][O:12][CH2:13][CH3:14])[C:6]=1[C:7](=[O:9])[NH2:8].CN(C)[CH:21]=[O:22]>>[CH2:13]([O:12][CH2:11][CH2:10][N:5]1[C:6]2[C:7](=[O:9])[NH:8][C:21](=[O:22])[NH:1][C:2]=2[C:3]([C:15]([O:17][CH3:18])=[O:16])=[N:4]1)[CH3:14]Participants
3
Procedure
A solution of the amide of step 4 (570 mg, 3.38 mmol) in N,N-dimethylformamide (30 mL) was treated with N,N′-carbonyldiimidazole (658 mg, 4.06 mmol) and the reaction mixture stirred at room temperature for 1 hour and then at 90° C. for 18 hours. The reaction mixture was concentrated in vacuo and the crude product suspended in acetone and sonicated for 30 minutes. The solid product was filtered off and dried in vacuo to yield the dione product. 1H NMR (DMSO-D6, 400 MHz) δ: 1.02 (t, 3H), 3.37 (m, 2H), 3.77 (m, 2H), 3.83 (s, 3H), 4.63 (m, 2H), 10.75 (s, 1H), 11.40 (s, 1H). MS ES−m/z 281 [M-H]−.