Linagliptin Impurity N Catalogue L562379 CAS 2416949-69-2 M.W 491.54 M.F C25H29N7O4 Specifications FAQs (R)-N-(2-acetylphenyl)-2-(8-(3-aminopiperidin-1-yl)-7-(but-2-yn-1-yl)-3-methyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-1-yl)acetamide