PROCESS FOR PREPARING SODIUM SALTS OR POTASSIUM SALTS OF 4-HYDROXY-2-OXO-2,5-DIHYDROFURAN-3-CARBOXYLATE

摘要

Process for preparing sodium or potassium salts of 4-hydroxy-2-oxo-2,5-dihydrofuran-3-carboxylic esters, comprising the reaction of a malonic ester with potassium hydroxide to give the corresponding malonic ester potassium salt of the formula (III) which is then reacted further with a chloroacetic ester to give a compound of the formula (V) followed by a ring closure reaction in which the compound of the formula (V) is reacted with a sodium or potassium alkoxide of the formula ZOR1 where R1, R2, R3 and K are each as defined in the description.