Linagliptin Dimer Impurity
Linagliptin IMP 8-[(3R)-3-Amino-1-piperidinyl]-1-[[4-[[2-[[8-[(3R)-3-amino-1-piperidinyl]-7-(2-butyn-1-yl)-2,3,6,7-tetrahydro-3-methyl-2,6-dioxo-1H-purin-1-yl]methyl]-1,4-dihydro-4-ethyl-4-quinazolinyl]methyl]-2-quinazolinyl]methyl]-7-(2-butyn-1-yl)-3,7-dihydro-3-methyl-