C([O:8][C:9]1[CH:18]=[C:17]2[C:12]([C:13](=[O:26])[NH:14][C:15]([C:19](=[O:25])[C:20]([CH3:24])([CH3:23])[CH2:21][CH3:22])=[N:16]2)=[CH:11][CH:10]=1)C1C=CC=CC=1.C(O)(=O)C>[Pd].C(OCC)(=O)C.CO.CN(C=O)C>[OH:8][C:9]1[CH:18]=[C:17]2[C:12]([C:13](=[O:26])[NH:14][C:15]([C:19](=[O:25])[C:20]([CH3:23])([CH3:24])[CH2:21][CH3:22])=[N:16]2)=[CH:11][CH:10]=15% Palladium-on-charcoal catalyst (0.7 g, 50% in water) was added to a solution of 7-benzyloxy-3-methylpivaloyl-3,4-dihydroquinazolin-4-one (6.85 g, 18.7 mmol) in ethyl acetate (300 ml), methanol (40 ml), DMF (40 ml), and acetic acid (0.7 ml). The mixture was vigorously stirred under hydrogen at atmospheric pressure for 4.5 hours. The catalyst was removed by filtration through diatomaceous earth, the filtrate concentrated by evaporation to about 60 ml, diluted with water (300 ml) and extracted with ether (3×300 ml). The combined extracts were washed with brine, dried (MgSO4), and the volatiles removed by evaporation. The resulting crude solid was dissolved in acetone (200 ml) and acetic acid (0.2 ml) and cooled to 0° C. Potassium permanganate (1.8 g) was added and the mixture stirred for 10 minutes. The reaction mixture was poured into water (250 ml) and ethyl acetate (250 ml) was added. The precipitate was removed ;by filtration, the organic phase separated and the aqueous phase re-extracted with ethyl acetate (2×100 ml). The combined extracts were washed with water and brine, dried (MgSO4) and the volatiles removed by evaporation to give 7-hydroxy-3-methylpivaloyl-3,4-dihydroquinazolin-4-one (4.05 g, 78%) as a cream solid.
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