Preparation method of edoxaban intermediate

The invention provides a preparation method of an edoxaban intermediate, the method is characterized in that the edoxaban intermediate is prepared by reacting a compound shown as a formula I with a compound shown as a formula II or salts thereof in the presence of organic alkali, oxalic acid is independently added in the reaction step, the reaction yield can be remarkably improved, and the impurity content in the product can be reduced. 本发明提供一种依度沙班中间体的制备方法，所述方法为在有机碱存在下，使化合物式I与化合物式II或其盐进行反应制备得到，在所述反应步骤中单独加入草酸，能够显著提高反应的产率并降低产物中的杂质含量。