Structure identification of the main degradation products of mirabegron

Objective:To identify the structure of the main degradation products of mirabegron.Methods:LC-MS was adopted to analyze the structure of four main degradation products of mirabegron. HPLC was performed on a COSMOSIL C 18 -MS-II（250 mm×4.6 mm,5 μm）column,using gradient elution with acetonitrile-0.1% trifluoroacetic acid buffer as the mobile phase at a flow rate of 1.0 m L·min -1 . Four main degradation products were separated from mirabegron by HPLC,and their structures were further identified by NMR and polarimeter. Results:The four main degradation products were the acylamino group hydrolysates:2-amino-4-thiazoleacetic acid,4-methylthiazol-2-amine,（R）-2-[（4-aminophenethyl）amino]-1-phenylethanol,and oximes of mirabegron:（Z）-benzaldehyde oxime. Conclusion:This method provides a scientific basis for selecting the conditions of mirabegron production and storage.