Improved Process for the Preparation of Montelukast: Development of an Efficient Synthesis, Identification of Critical Impurities and Degradants

An improved and scalable process for the production of montelukast (Singulair, drug for asthma) based on a new and advantageous method of carrying out the key substitution reaction has been developed. The present procedure is distinguished from the previous solutions in the use of linear or cyclic polyethers, which ensures higher selectivity of the key step. The improved process for the preparation of montelukast is able to minimize a content of impurities and allows the effective production of montelukast and its scale-up.