[CH2:1]([C:3]1[C:4]([O:18][CH3:19])=[N:5][C:6]2[N:7]([CH:10]=[C:11]([C:13]([O:15]CC)=[O:14])[N:12]=2)[C:8]=1[CH3:9])[CH3:2].C(=O)([O-])[O-].[K+].[K+]>CO.O>[CH2:1]([C:3]1[C:4]([O:18][CH3:19])=[N:5][C:6]2[N:7]([CH:10]=[C:11]([C:13]([OH:15])=[O:14])[N:12]=2)[C:8]=1[CH3:9])[CH3:2]A mixture of 120 g (0.456 mmol) of ethyl 6-ethyl-7-methoxy-5-methylimidazo[1,2-a]pyrimidine-2-carboxylate and 120 g of potassium carbonate in 1200 ml of methanol and 600 ml of water was heated at reflux for 2 hours and the methanol was then evaporated. 150 ml of more water were added, and the resulting solution was acidified to a pH of 1 with concentrated HCl. The solid obtained was filtered and was washed with water, then dried under vacuum over P2O5 at 80° C. to obtain 87.43 g (82% yield) of 6-ethyl-7-methoxy-5-methylimidazo[1,2-a]pyrimidine-2-carboxylic acid.
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