Linagliptin Impurity 8 Catalogue L562358 M.W 500.55 M.F C26H28N8O3 Specifications FAQs (S)-N-(1-(7-(But-2-ynyl)-3-methyl-1-((4-methylquinazolin-2-yl)methyl)-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl)piperidin-3-yl)formamide