[C:1]([CH2:3][NH:4][C:5]([NH2:7])=[O:6])#N.[OH-:8].[Na+].O.[C:11]([OH:15])(=[O:14])[CH:12]=O>CO>[C:11]([OH:15])(=[O:14])[C:12]1[NH:7][C:5](=[O:6])[NH:4][C:3](=[O:8])[CH:1]=1A suspension of 57 g of cyanomethylurea in 45 ml of methanol is heated to boiling under agitation, combined with 3 ml of 8N sodium hydroxide solution, and heated under reflux for 30 minutes. The reaction mixture is then allowed to cool down to 30° C., 550 ml of water and 90 g of 50% strength glyoxylic acid are added thereto, and the mixture is neutralized with 8N sodium hydroxide solution at a temperature of maximally 30° C. until a pH of 6.5 has been attained. The mixture is then heated to 55°-60° C., 225 ml of 8N sodium hydroxide solution is added dropwise thereto at this temperature within one hour, and the mixture is stirred for another 2 hours. Then about 150 ml of aqueous methanol is removed by distillation to 95° C.; the mixture is heated for one hour under reflux and gently acidified with concentrated nitric acid. The mixture is allowed to cool down to room temperature, the thus-separated crystallized product is filtered off, washed with water, and dried under vacuum, thus obtaining 72 g of orotic acid (=71.8% of theory).
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