A synthetic process for the preparation of amino acid esters such as methylphenidate and analogs thereof is disclosed. The process involves reacting an amino acid such as α-phenyl-α-(2-piperidinyl)acetic acid or an analog thereof with an alcohol such as methanol in the presence of an acid and a water sequestrant such as trimethyl orthoacetate. In some embodiments, the water sequestrant is added to the reaction mixture after an initial period of esterification and then the reaction is allowed to continue. The α-phenyl-α-(2-piperidinyl)acetic acid methyl ester or analog thereof is then isolated from the reaction mixture. In one variation of the process, the supernatant liquid may be recycled in subsequent runs to increase yield and product purity.
揭示了一种用于制备
氨基
酸酯类化合物(如甲基
苯丙酸酯及其类似物)的合成过程。该过程涉及在酸和
水分离剂(如三甲基正
乙酸酯)的存在下,将
氨基酸(如α-苯基-α-(2-
哌啶基)
乙酸或其类似物)与醇(如
甲醇)反应。在某些实施例中,
水分离剂在酯化的初始阶段后加入反应混合物,然后允许反应继续进行。然后,从反应混合物中分离出α-苯基-α-(2-
哌啶基)
乙酸甲酯或其类似物。在该过程的一个变种中,上清液可以在后续运行中回收,以增加产量和产品纯度。