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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.

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The amino alcohols in l-valinol were effectively separated and quantified using hydrophilic interaction chromatography with fluorescence detection. The influence of the mobile phase (salt type, buffer concentration, and pH) on retention was studied. A column TSKgel amide and mobile phase consisting of 10 mM acetate buffer pH 4.0 and acetonitrile (20:80, v/v) provided well-separated symmetric peaks of analytes. Fluorescence detection was performed using postcolumn derivatization with o-phtaldialdehyde/2-mercaptoethanol at an excitation and emission wavelength of 345 and 450 nm, respectively. Simple sample pretreatment and very high sensitivity represent the main advantages of the developed method. After validation, the method was successfully applied to the analysis of commercial samples of l-valinol.