C[O:2][C:3]1[N:12]=[CH:11][C:10]2[CH2:9][CH2:8][C:7]3[C:13]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[N:14][N:15]([CH3:16])[C:6]=3[C:5]=2[N:4]=1.[I-].[Na+].C[Si](Cl)(C)C.CO>C(#N)C>[OH:2][C:3]1[N:12]=[CH:11][C:10]2[CH2:9][CH2:8][C:7]3[C:13]([C:17]([O:19][CH2:20][CH3:21])=[O:18])=[N:14][N:15]([CH3:16])[C:6]=3[C:5]=2[N:4]=1
1.5 g (5.2 mmol) of ethyl 8-methoxy-1-methyl-4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline-3-carboxylate were dissolved in 90 mL of acetonitrile and 1.6 g (10.6 mmol) of sodium iodide and 1.5 mL of trimethylsilylchloride were added. After a day under stirring and nitrogen atmosphere at room temperature the solvent was evaporated, the residue redissolved with a mixture dichloromethane/methanol 4/1 and washed with a saturated aqueous solution of Na2S2O3. The organic layer was dried over Na2SO4 and evaporated to dryness. The residue crystallized from methanol leading 1.1 g of the title compound (78% yield).
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