| 摘要 |
PURPOSE:To obtain the titled compound free from coloring component, by phosgenating an essentially anhydrous lysine monoalkyl ester trihydrochloride obtained by dehydration treatment, removing the solvent and tar from the ester, and heat-treating and fractionating the product. CONSTITUTION:The lysine monoalkyl ester trihydrochloride of formula I (R is 2-5C alkyl) is dispersed in a non-aqueous organic solvent (e.g. benzene), and dehydrated by the filtration and the washing of the filter cake with a non- aqueous organic solvent to obtain an essentially anhydrous salt. The salt is converted to the lysine ester tricyanate of formula II by phosgenation reaction, the solvent and tar are removed from the reaction liquid, and the product is fractionated after the heat-treatment at 100-200 deg.C, preferably 160-190 deg.C. The formation of colored impurities in the fractionation process can be suppressed by the dehydration and the phosgenation of the hydrated raw material causing the discoloration, and the removal of tar from the product.
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