Glyoxylic Acid → 1-Benzyl-5-hydroxyimidazolidine-2,4-dione

Participants

Reaction Conditions

Reaction Steps

3000 parts by weight of 50% strength aqueous glyoxylic acid solution and 500 parts by weight of acetic acid (100% strength) are placed in a heatable, stirred apparatus and heated to 100° C. A mixture of 3000 parts by weight of benzylurea, 1300 parts by weight of water and 1500 parts by weight of acetic acid having a temperature of 80° C. is added to this solution over a period of one hour. The total reaction mixture is subsequently stirred at an internal temperature of 100° C. for another hour. 4500 parts by weight of an acetic acid/water mixture are then distilled off to a pressure of 200 mbar and a temperature at the bottom of 100° C. The remaining liquid residue is admixed at 90° C. with 900 parts by weight of water and 12.5 parts by weight of acetic acid, cooled to 35° C., admixed with 3000 parts by weight of methylene chloride and stirred at 25° C. for 12 hours. The temperature is then held at 3° C. for 1 hour by cooling.

Provenance & Evidence