Linagliptin N-BOC Impurity Catalogue L562365 CAS 668273-75-4 M.W 572.66 M.F C30H36N8O4 Specifications FAQs N-[(3R)-1-[7-(2-Butyn-1-yl)-2,3,6,7-tetrahydro-3-methyl-1-[(4-methyl-2-quinazolinyl)methyl]-2,6-dioxo-1H-purin-8-yl]-3-piperidinyl]-carbamic acid 1,1-dimethylethyl ester