Linagliptin Impurity 7 Catalogue L562357 M.W 491.54 M.F C25H29N7O4 Specifications FAQs (R)-N-(2-Acetylphenyl)-2-(8-(3-aminopiperidin-1-yl)-7-(but-2-ynyl)-3-methyl-2,6-dioxo-2,3-dihydro-6H-purin-1(7H)-yl)acetamide