The Linagliptin with CAS registry number of 668270-12-0 is also called 1H-Purine-2,6-dione,8-[(3R)-3-amino-1-piperidinyl]-7-(2-butyn-1-yl)-3,7-dihydro-3-methyl-1-[(4-methyl-2-quinazolinyl)methyl]-. The IUPAC name is 8-[(3R)-3-aminopiperidin-1-yl]-7-(but-2-yn-1-yl)-3-methyl-1-[(4-methylquinazolin-2-yl)methyl]-3,7-dihydro-1H-purine-2,6-dione. In addition, the formula is C₂₅H₂₈N₈O₂ and the molecular weight is 472.54222.

Physical properties about Linagliptin are: (1)ACD/LogP: 2.99; (2)# of Rule of 5 Violations: 1; (3)ACD/LogD (pH 5.5): -1; (4)ACD/LogD (pH 7.4): 0; (5)ACD/BCF (pH 5.5): 1; (6)ACD/BCF (pH 7.4): 1; (7)ACD/KOC (pH 5.5): 1; (8)ACD/KOC (pH 7.4): 1; (9)#H bond acceptors: 10; (10)#H bond donors: 2; (11)#Freely Rotating Bonds: 5; (12)Polar Surface Area: 113.48 Å²; (13)Index of Refraction: 1.717; (14)Molar Refractivity: 133.069 cm³; (15)Molar Volume: 338.019 cm³; (16)Polarizability: 52.753 ×10^-24cm³; (17)Surface Tension: 59.137 dyne/cm; (18)Density: 1.398 g/cm³; (19)Flash Point: 353.675 °C; (20)Enthalpy of Vaporization: 97.285 kJ/mol; (21)Boiling Point: 661.189 °C at 760 mmHg; (22)Vapour Pressure: 0 mmHg at 25°C.

The mechanism of action about this chemical: It is an inhibitor of DPP-4 which degrades the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Both GLP-1 and GIP increase insulin biosynthesis and secretion from pancreatic beta cells in the presence of normal and elevated blood glucose levels. Thus, this chemical stimulates the release of insulin in a glucose-dependent manner and decreases the levels of glucagon in the circulation.

You can still convert the following datas into molecular structure:
(1)SMILES: O=C2N(c1nc(n(c1C(=O)N2Cc4nc3ccccc3c(n4)C)CC#CC)N5CCC[C@@H](N)C5)C
(2)InChI: InChI=1/C25H28N8O2/c1-4-5-13-32-21-22(29-24(32)31-12-8-9-17(26)14-31)30(3)25(35)33(23(21)34)15-20-27-16(2)18-10-6-7-11-19(18)28-20/h6-7,10-11,17H,8-9,12-15,26H2,1-3H3/t17-/m1/s1
(3)InChIKey: LTXREWYXXSTFRX-QGZVFWFLBX