The invention relates to a process for the preparation of aspartylphenylalanine methyl ester from N-formylaspartylalanine methyl ester by treatment with an acid, characterized in that N-formylaspartylalanine methyl ester is treated at 30-60◊C with at least 0.5 molar equivalent oxalic acid per mole of N-formyl-aspartylphenylalanine methyl ester in a solvent mixture in which N-formylaspartylphenylalanine methyl ester dissolves well and in which the oxalic acid salt of aspartylphenylalanine methyl ester is poorly soluble, after which the oxalic acid salt of aspartylphenylalanine methyl ester is removed by filtration, dissolved in water and subsequently neutralized with the aid of an inorganic base with formation of free aspartylphenylalanine methyl ester.
本发明涉及一种通过酸处理从N-甲酰基天冬
氨酰苯丙
氨酸甲酯制备天冬
氨酰苯丙
氨酸甲酯的工艺,其特征在于N-甲酰基天冬
氨酰苯丙
氨酸甲酯在30-60◊C的温度下用每摩尔N-甲酰基天冬
氨酰苯丙
氨酸甲酯至少0.5摩尔当量的
草酸在混合溶剂中进行处理,N-甲酰基天冬
氨酰苯丙
氨酸甲酯在混合溶剂中溶解良好,而天冬
氨酰苯丙
氨酸甲酯的
草酸盐在混合溶剂中溶解不良、然后通过过滤除去天冬苯丙
氨酸甲酯的
草酸盐,将其溶解在
水中,然后借助
无机碱进行中和,形成游离的天冬苯丙
氨酸甲酯。