A novel process for the preparation of omeprazole and its enantiomers, such as esomeprazole, as well as the preparation of related 2-(2-pyridinylmethyl-sulphinyl)-1H-benzimidazoles, including pantoprazole, lansoprazole and rabeprazole, as recemates or single enantiomers, and their alkali or alkaline salts has been developed. The novel process involves the surprising discovery that protection of the free-base benzimidazole sulfoxide (e.g. omeprazole or esomeprazole), by reaction with an alkyl, aryl or aralkyl chloroformate following oxidation of the corresponding sulfide, eliminates the need for its direct isolation. Subsequent removal of the protecting group with a solution of alkali or alkaline earth alkoxide in a C1-C4 alcohol directly provides the corresponding salt. By eliminating the need to handle the free-base benzimidazole sulfoxide, this advantageous procedure provides increased chemical yields over processes described in the art.
一种新型制备
奥美拉唑及其对映体(如左旋
奥美拉唑)以及相关的2-(2-
吡啶甲基-亚砜基)-1H-
苯并咪唑类化合物(包括
泮托拉唑、
兰索拉唑和
雷贝拉唑)的方法已经开发出来。这种新型方法涉及到一个惊人的发现,即通过与烷基、芳基或芳基
氯甲酸酯反应保护游离基
苯并咪唑亚砜氧化物(例如
奥美拉唑或左旋
奥美拉唑),随后通过对应
硫醚的氧化消除了对其直接分离的需求。随后,通过使用C1-C4醇中碱或碱土
金属烷氧化物溶液去除保护基,直接得到相应的盐。通过消除处理游离基
苯并咪唑亚砜氧化物的需求,这种优势的程序提供了比文献中描述的工艺更高的
化学产率。