[CH3:1][N:2]1[C:6]([O:7][CH3:8])=[C:5]([CH:9]=[O:10])[C:4]([CH3:11])=[N:3]1.O.[Mn]([O-])(=O)(=O)=[O:14].[K+].[OH-].[NH4+]>CO.CC(C)=O.C(O)(=O)C>[CH3:1][N:2]1[C:6]([O:7][CH3:8])=[C:5]([C:9]([OH:14])=[O:10])[C:4]([CH3:11])=[N:3]12.5 g (0.0162 mole) of 1,3-dimethyl-5-methoxy-4-pyrazole carboxaldehyde (prepared as described in Khim. Farm. Zh, 4, 19 (1970) [CA, 73, 3844 w, (1970)] was dissolved in a solution containing 50 ml of water, 2 ml of acetic acid and 0.6 ml of acetone. 2.56 g (0.0162 mole) of potassium permanganate was added in several portions. The reaction was stirred for 3 hours before decomposing the excess potassium permanganate with 3 ml of methanol and then made alkaline with ammonium hydroxide, heated on the steam bath for 1/2 hour, and filtered. The filtrate was evaporated to approximately 30 ml of solution which was then acidified to pH4 with concentrated HCl. The solid was then collected. 1.6 g (58% yield) was obtained, m.p. 179°-180° C., white solid.
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