Process for the preparation of L-carnitine
wherein: a) The ester of 4-azido-3-ketobutyric acid, with formula:
wherein R is an alkyl or arylalkyl radical, is placed in contact, in the liquid phase, in the presence of a source of carbon and of a phosphate buffer, with a microorganism, to yield the ester of 4-azido-3-hydroxybutytic acid of formula:
wherein R has the above-reported meaning, in the form of the (3R) isomer only; b) the compound so obtained is submitted to hydrolysis of the ester group, in the presence of a base, to yield (3R)-4-azido-3-hydroxybutyric acid, with formula:
c) (3R)-4-azido-3-hydroxybutyric aid is submitted to hydrogenation of azido group with hydrogen gas, and in the presence of a hydrogenation catalyst, to yield -(3R)-4-amino-3-hydroxybutyric acid [(-)-GABOBI, with formula:
d) The so-obtained compound is separated and recovered by crystallization; e) (3R)-4-amino-3-hydroxybutyric acid is submitted to methylation to yield L-carnitine compound (I).
左旋肉碱的制备工艺
a) 4-
叠氮-3-酮
丁酸的酯,其式为
式中 R 为烷基或芳基烷基的 4-
叠氮-3-酮
丁酸酯在液相中,在碳源和
磷酸盐缓冲液存在下,与微
生物接触,生成式中的 4-
叠氮-3-羟基
丁酸酯:
其中 R 具有上述含义,仅以 (3R) 异构体的形式存在;b) 在碱存在下,将这样得到的化合物进行酯基
水解,得到式为 (3R)-4-azido-3-hydroxybutyric acid 的 (3R)-4-azido-3-hydroxybutyric acid:
c)(3R)-4-
叠氮-3-羟基
丁酸在
氢气和氢化催化剂存在下进行
叠氮基氢化反应,得到-(3R)-
4-氨基-3-羟基丁酸[(-)-加波比,其式为(-)-加波比]:
(3R)-4-amino-3-hydroxybutyric acid[(-)-GABOBI,式中:(-)-GABOBI;(-)-(3R)-
4-氨基-3-羟基丁酸;(-)-(3R)-
4-氨基-3-羟基丁酸