Preparation method of degarelix key dipeptide intermediate

The invention relates to a preparation method of a degarelix key dipeptide intermediate. According to the invention, N'-L-hydrogenated whey acyl-N-9-fluorenylmethyloxycarbonyl-4-amino-L-phenylalanineand 4-carbamido-D-phenylalanine benzyl trifluoroacetate are subjected to condensation, purification, reduction, purification and other steps to obtain a degarelix IV compound N-fluorenylmethyloxycarbonyl-4-[[[(4S)-hexahydro-2,6-dioxo-4-pyrimidinyl] carbonyl] amino]-L-phenylalanyl-4-carbamido-D-phenylalanine. The preparation method of the invention can effectively avoid and remove the impurities generated in the synthesis of the polypeptide, and prepare the degarelix polypeptide fragment with high purity and high yield. 本发明涉及地加瑞克关键二肽中间体的制备方法。N'-L-氢化乳清酰-N-9-芴甲氧羰基-4-氨基-L-苯丙氨酸和4-脲基-D-苯丙氨酸苄酯三氟乙酸盐经缩合、纯化、还原、纯化等步骤得到地加瑞克式Ⅳ化合物N-芴甲氧羰基-4-[[[(4S)-六氢-2,6-二氧代-4-嘧啶基]羰基]氨基]-L-苯丙氨酰-4-脲基-D-苯丙氨酸。本发明的制备方法能够有效避免和除去多肽合成中的产生的杂质，高纯度高收率的制备地加瑞克多肽片段。