Sulfate Ion → HCID 178469851, compound

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Reaction Steps

The applicant company has found that the operation can more advantageously be carried out in water: an aqueous solution of 1 mol of the neutral sulphate of O-methylisourea (concentration of between 5 and 10%) has the corresponding amount (2 mols) of ethyl ethoxymethylenemalonate added thereto, and the mixture is stirred vigorously so as to keep the second reagent emulsified. An aqueous solution of an alkali metal hydroxide is then added thereto at a rate such that the temperature of the mixture remains between 20° and 30° C. The mixture is stirred for another two hours at room temperature, after the addition of the alkaline reagent. If sodium hydroxide solution is used as the reagent, the sodium salt of the ester (XVI) precipitates in the medium which is brought to pH 5 by the addition of an inorganic or organic acid when the reaction has finished. The solution obtained, which is filtered if necessary in order to remove a small amount of insoluble matter, is extracted with an appropriate solvent chosen, preferably, from the polyhalogenated aliphatic hydrocarbons, more especially chloroform. After washing and drying the organic solution, evaporation in vacuo leaves 5-ethoxycarbonyl-4-hydroxy-2-methoxy-pyrimidine (XVI), which is practically pure, with a yield of about 80%. The product can then be purified by recrystallisation from a suitable solvent, especially isopropanol.

Provenance & Evidence